Power steering hose replacements/substitutes

[1991 Corvette ZR-1]

Hello all,

I think it?s about time to pull my rack and pinion and send out to Turn One for a rebuild. At lower speeds it doesn?t feel too bad, but noticeable slack until it feels like the wheels are responding. At anything above interstate speeds, the term numb even seems an understatement, more like nerve wracking. While I have the rack out, I?ll rebuild the power steering pump and replace what I can with the hoses. The car is at 90,000 miles.

I?m curious as to anyone?s substitute hoses or part numbers for using in place of the factory hoses that may not be available.

[secondchance]

Hello all,

I think it?s about time to pull my rack and pinion and send out to Turn One for a rebuild. At lower speeds it doesn?t feel too bad, but noticeable slack until it feels like the wheels are responding. At anything above interstate speeds, the term numb even seems an understatement, more like nerve wracking. While I have the rack out, I?ll rebuild the power steering pump and replace what I can with the hoses. The car is at 90,000 miles.

I?m curious as to anyone?s substitute hoses or part numbers for using in place of the factory hoses that may not be available.

I?ll share my experience with C4 steering I had with 84 Z51 and 94 ZR-1.
84 after about 80,000 miles started to exhibit what is called morning sickness. This is a sysmtom, when the car is cold, experiencing momentary lack of power assist. This sysmtom, I believe, comes from deterioration of internal O ring and require rebuild.
With my 94, at around 130,000 miles, started to notice sloppiness especially between left and right - at center. Long story short, I too had the rack rebuilt at Turn One (best outfit for C4 rack rebuild best I can tell) and during the install, noticed lower control arm bushings at the rear had worn out to a point where rear of lower control arm was moving as much as 1/8?. I replaced both rear bushings (left and right). This improved the situation but did not cure the vague fell completely. Removing the steering rod, I could tell that there was tiny sloppiness at the rag joint. This tiny slop, at the steering wheel was getting amplified to as much as 1/4?.
While removing and replacing the rack, go through those components I described.
As far as hoses, they are ZR-1 specific but you should be able to reuse without replacing.

[rkreigh]

they are a bit hard to get. But I found a tip. if the ends are bad, look up a trucker buddy. They get hydraulic hoses made up custom all the time and it's affordable. I'd like to use some nice aftermarket braided hose that would look cool

[1991 Corvette ZR-1]

Thank you for the recommendations. Had a fellow forum member hook me up with a new replacement pressure side hose. The rack is out and I knew it would be rough in the area behind the power steering pump but more than I was expecting. I tried to cheat removing the PS pump and reservoir by sliding it down into the empty space the rack had occupied. No dice.

Have to drain the coolant and remove part of the coolant system per the FSM. Attaching some pics to see what could be causing the leak. The lower end cam plug was a little wet. As for the rest deep down...guess I won?t know until I crawl under and start cleaning. Turn One has a turnaround time of about 3 or 4 weeks so I guess that gives me time to clean and pinpoint the leak.

[1991 Corvette ZR-1]

I cleaned things up a little for a start. There?s actually an LT5 under that stuff. The bottom of the compressor is caked. Part of me wonders if there was a leak from the compressor but that?s too convenient. I?m going to say it?s most likely the front pan bolts are loose and seeped oil which has covered most of the front of the block over the years.

[HAWAIIZR-1]

It looks like you are doing a nice job there Jamall. It does not look like a current leak so curious to know what you find. Best wishes with the repair.


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[1991 Corvette ZR-1]

It looks like you are doing a nice job there Jamall. It does not look like a current leak so curious to know what you find. Best wishes with the repair.


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Thanks, Craig. I do have an ?artifact? I kept for future reference that I found in the cradle a year or so back while cleaning. Maybe sharper eyes can identify this but to me, it looks like a piece of the original factory front cover gasket. So someone has been in here for work. Wether it was the front cover leaking or water pump related, I?m not sure.

I remember the PVC box gasket I replaced had the same blue pinstripe, so I am assuming this is a piece of an original factory gasket. I?m aware of the oil pan bolts loosening but have never heard of the front cover bolts doing the same. I?ll check torque of what cover bolts I can from under the car now that the rack is out.

[Dynomite]

So someone has been in here for work. Wether it was the front cover leaking or water pump related, I?m not sure.


Water Pump gasket 👍

[HAWAIIZR-1]

Thanks, Craig. I do have an ?artifact? I kept for future reference that I found in the cradle a year or so back while cleaning. Maybe sharper eyes can identify this but to me, it looks like a piece of the original factory front cover gasket. So someone has been in here for work. Wether it was the front cover leaking or water pump related, I?m not sure.



I remember the PVC box gasket I replaced had the same blue pinstripe, so I am assuming this is a piece of an original factory gasket. I?m aware of the oil pan bolts loosening but have never heard of the front cover bolts doing the same. I?ll check torque of what cover bolts I can from under the car now that the rack is out.



You are welcome. I agree with Dynomite and he has Bingo. One thing always seems to lead to another with our cars.


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[1991 Corvette ZR-1]

Thanks, guys. That?s a relief and it makes sense because the water pump did look a little brighter than the surrounding aluminum. Rack is all crated up and shipping out tomorrow. It?s probably overkill but I?d rather pay extra and have piece of mind the hard lines are not in danger.

[1991 Corvette ZR-1]

I?m trying to do this the honest way and remove the driver side coolant tube to get the pump out. Coolant is drained and a T30 torx bit fits snug in ONE of the four torx bolts holding the tube on the injector housing. The others, it fits a little loose for my liking...just begging to be stripped. Is there a specific size everyone else uses? I?m thinking of picking up a T35 bit to try. Worst case, if some strip out, what process is tried and true to extract them? I know about EZ outs but I?m open to a ?fine tuned? method for these particular bolts. One of the least reliable fasteners and they?re everywhere on this engine.

[secondchance]

Those are tricky bolts to get out. Can?t remember what size torx since when I attempted was 6 years ago. I removed some but a couple were corroded and wouldn?t budge. I ended up shipping them to leegaff since he was porting IH and plenum for me anyway.

[HAWAIIZR-1]

Jamall,

I hope this does not end up a Power steering hose....and then some. [emoji38]Roadster (Tom) has a Throttle Body removal and then some thread. It seems like every time I touch something on the Z it is ...,and then some. Best wishes with the project. 🤙🏼[emoji1303]


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[secondchance]

Jamall,

I hope this does not end up a Power steering hose....and then some. [emoji38]Roadster (Tom) has a Throttle Body removal and then some thread. It seems like every time I touch something on the Z it is ...,and then some. Best wishes with the project. 🤙🏼[emoji1303]


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I know about.... and then some. It went on for 7 years and then some...

[HAWAIIZR-1]

I know about.... and then some. It went on for 7 years and then some...



🤣 The story of our lives.....


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[Roadster]

Haha....my middle name is "and then some"....lol
Looks like you got the rack out without any major problems Jamall...you have me rethinking about removing mine....especially with everything out of the way....
I am hesitant because of the one bolt that backs out to the front engine cover as per the thread from secondchance on his rack removal...
Just don't want to run into anymore potential issues than I already have.....lol
1469114692

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[HAWAIIZR-1]

Haha....my middle name is "and then some"....lol



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[emoji38] Tom, Your and then some leads to some good projects so it is all good!





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[1991 Corvette ZR-1]

That bolt securing the rack to the cradle came out just barely, with gentle negotiation. It is a tad too long and I am wondering if shortening the bolt for clearance would be an issue. When they mention space is a premium due to the LT5 dimensions in Heart of The Beast, they were not kidding. This is snowballing into more than a rack change for the moment, as it is all apart now and the rack will not be back for at least four weeks from Turn One.

[Roadster]

[emoji38] Tom, Your and then some leads to some good projects so it is all good!

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Thanks Craig :)....there is always something to do....hopefully I am getting near the end.....I think....:dontknow:


That bolt securing the rack to the cradle came out just barely, with gentle negotiation. It is a tad too long and I am wondering if shortening the bolt for clearance would be an issue. When they mention space is a premium due to the LT5 dimensions in Heart of The Beast, they were not kidding. This is snowballing into more than a rack change for the moment, as it is all apart now and the rack will not be back for at least four weeks from Turn One.

This is what Phil (Jagdpanzer) recommended to do with this bolt.....
"Tom,
When we R&Red Yun's power steering rack a while back the long chassis bracket bolt was real challenge to get out. This can be improved for future removal by inserting the bolt from the other direction with nut on the top side as shown in this photo."

I will have to look at that bolt today.....how much of a "gentle negotiation" did you need to do removing this bolt....as I don't want to put myself into a situation to where I can't get out.....:)

[HAWAIIZR-1]

Thanks Craig :)....there is always something to do....hopefully I am getting near the end.....I think....


14702



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[1991 Corvette ZR-1]

Thanks Craig :)....there is always something to do....hopefully I am getting near the end.....I think....:dontknow:




This is what Phil (Jagdpanzer) recommended to do with this bolt.....
"Tom,
When we R&Red Yun's power steering rack a while back the long chassis bracket bolt was real challenge to get out. This can be improved for future removal by inserting the bolt from the other direction with nut on the top side as shown in this photo."

I will have to look at that bolt today.....how much of a "gentle negotiation" did you need to do removing this bolt....as I don't want to put myself into a situation to where I can't get out.....:)

Once I had the nut off, I pushed the bolt up as far as it would go. Which I thought would be all the way out but it came into contact with the engine. So I reached in and was able to grab the head of the bolt and wiggle it to an angle like it was glancing off the engine. I then went back under the car with a Phillips screw driver and a hammer and gently tapped it and it came out. If you look at the block where it came into contact with it you can probably see a scratch mark where it rubbed against the engine as it was tapped out but nothing anyone will ever see.

I may take out the angle grinder and remove a thread or two off so it clears slightly easier going back in.

[1991 Corvette ZR-1]

Were any of you aware of that part in the FSM that says in order to remove the PS pump and reservoir from the engine, you have to take your top end off and send it out for porting? I missed that step, but that is what is happening. I cannot get the coolant tube bolts to budge, so I am taking the top end off and crating it in a few days to send out to Pete for porting. He was generous enough to offer to remove the bolts. I did not feel like breaking it down today, instead I was chasing some oil leaks on the underside and I have some pictures. Hoping for some answers I want to hear.

So there is a sensor right next to the oil dipstick tube that was wet with oil and has been seeping it onto the bottom of the pan. When I unplugged it, the connector was soaked in oil. So I am guessing this sensor has failed internally and is leaking oil. Is there an available replacement for this part? I had the same issue with the low oil level sensor which also appears to be leaking oil out the connector. Also, there is a block off just ahead of the passenger O2 connector that is wet.l and it looks very difficult to reach. One bolt might be reachable. The other one not sure about. I should not be surprised as the parts are 30+ years old.

I have been losing oil fast on small trips and it?s a collection of leaks from thes sensor locations and possibly the pan have added up together.

[HAWAIIZR-1]

Were any of you aware of that part in the FSM that says in order to remove the PS pump and reservoir from the engine, you have to take your top end off and send it out for porting? I missed that step, but that is what is happening. I cannot get the coolant tube bolts to budge, so I am taking the top end off and crating it in a few days to send out to Pete for porting. He was generous enough to offer to remove the bolts. I did not feel like breaking it down today, instead I was chasing some oil leaks on the underside and I have some pictures. Hoping for some answers I want to hear.



So there is a sensor right next to the oil dipstick tube that was wet with oil and has been seeping it onto the bottom of the pan. When I unplugged it, the connector was soaked in oil. So I am guessing this sensor has failed internally and is leaking oil. Is there an available replacement for this part? I had the same issue with the low oil level sensor which also appears to be leaking oil out the connector. Also, there is a block off just ahead of the passenger O2 connector that is wet.l and it looks very difficult to reach. One bolt might be reachable. The other one not sure about. I should not be surprised as the parts are 30+ years old.



I have been losing oil fast on small trips and it?s a collection of leaks from thes sensor locations and possibly the pan have added up together.



Yep! And then some......

Sorry to hear this. Yes, top end porting is in the FSM. [emoji38] While you are in there tips!

See this post for one of your questions. I could not tell what you meant about the second one.

http://www.zr1.net/forum/showthread.php?t=25144&page=2


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[secondchance]

First sensor next to the dipstick tube is crankshaft sensor. My experience with oil leak around crankshaft sensor is due to "O" ring. I found slightly larger "O" ring.
Send me your mailing address and i will send you a couple.

[1991 Corvette ZR-1]

First sensor next to the dipstick tube is crankshaft sensor. My experience with oil leak around crankshaft sensor is due to "O" ring. I found slightly larger "O" ring.
Send me your mailing address and i will send you a couple.

Thank you for the offer. By the time I read this, I had already ordered the replacement sensor. It was about $15 through Corvette Central. I will keep your offer in mind though, could not hurt to have the extra O rings on hand. Maybe you or someone else could point me in the right direction for the correct terminal removal tool. My TPS connector literally came apart as I unplugged it. I have some pick tools but they are not the right kind to release these terminals. Top end is crated up and off to Pete. Turn One just got my rack and pinion today. Thank you for the new pressure hose, Craig. So this is what they look like without 30+ years of service on them. It looks too pretty to install!

[secondchance]

This should work.
https://www.jbtools.com/lisle-14900-wire-terminal-tool-for-pack-con-and-weather-pack-gm-c3/?gclid=EAIaIQobChMIooG8pu6D7wIVpdSzCh0FpwGNEAQYAiA BEgIBAvD_BwE

There use to be a GM connector website. If I find it, I?ll post it.

Is that for TPS?

[HAWAIIZR-1]

Thank you for the offer. By the time I read this, I had already ordered the replacement sensor. It was about $15 through Corvette Central. I will keep your offer in mind though, could not hurt to have the extra O rings on hand. Maybe you or someone else could point me in the right direction for the correct terminal removal tool. My TPS connector literally came apart as I unplugged it. I have some pick tools but they are not the right kind to release these terminals. Top end is crated up and off to Pete. Turn One just got my rack and pinion today. Thank you for the new pressure hose, Craig. So this is what they look like without 30+ years of service on them. It looks too pretty to install!


Your project is looking good Jamall! Glad to hear the hose made it okay and to your liking. Wow! A top end crated up for shipping too! It will be nice to have that new R&P too. Best wishes with your progress and can?t wait to see and hear when done too. [emoji1303]🤙🏼




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[1991 Corvette ZR-1]

I know this topic has gotten off track a bit but rather than clutter up the tech section with multiple threads, I wanted to keep the bulk of my questions here. So it looks like I MAY be able to reach the oil pressure regulator block off plate bolts if I remove the water pump hose. I have silicone hoses installed everywhere else except for this last hose which I let stay due to how tricky it looked getting out.

I have looked and looked and the smooth hose clamps I would use to secure the new silicone hose in place look tricky. As in there does not appear to be a good angle of attack to properly tighten the hose end connected to the thermostat housing. Has anyone used the factory clamps on these silicone hoses? The water pump connection appears doable, it is just the end that slips over the thermostat housing looks impossible with using the screw type hose clamp.

[secondchance]

I know this topic has gotten off track a bit but rather than clutter up the tech section with multiple threads, I wanted to keep the bulk of my questions here. So it looks like I MAY be able to reach the oil pressure regulator block off plate bolts if I remove the water pump hose. I have silicone hoses installed everywhere else except for this last hose which I let stay due to how tricky it looked getting out.

I have looked and looked and the smooth hose clamps I would use to secure the new silicone hose in place look tricky. As in there does not appear to be a good angle of attack to properly tighten the hose end connected to the thermostat housing. Has anyone used the factory clamps on these silicone hoses? The water pump connection appears doable, it is just the end that slips over the thermostat housing looks impossible with using the screw type hose clamp.

One word of caution - my experience with silicone hoses are that they require periodic tightening. This may be caused by properties of silicone or type of hose clamps necessitated by silicone hoses. Either way, I prefer to avoid using silicone hoses where periodic tightening would be difficult.

I don't know exactly what you mean by factory clamp (type you compress two tabs to loosen?). I am using screw type clamp for coolant hose to thermostat housing and not too difficult to tighten from below.

Below is the hose clamp I am using for all silicone hoses.
http://www.breezehoseclamps.com/breeze/liner/

[1991 Corvette ZR-1]

One word of caution - my experience with silicone hoses are that they require periodic tightening. This may be caused by properties of silicone or type of hose clamps necessitated by silicone hoses. Either way, I prefer to avoid using silicone hoses where periodic tightening would be difficult.

I don't know exactly what you mean by factory clamp (type you compress two tabs to loosen?). I am using screw type clamp for coolant hose to thermostat housing and not too difficult to tighten from below.

Below is the hose clamp I am using for all silicone hoses.
http://www.breezehoseclamps.com/breeze/liner/

Yeah, the factory compression clamp. Good call on the shrinking of the silicone, looks like I am using the smooth hose clamps I have. Back on the creeper and under the car again to have a look. Do you mind posting a picture of your clamp placement on the hose connected to the thermostat housing? I am trying to have the hex head/ flat blade fastener side face out to the passenger side or point toward the overflow tank, so I can snake a tool in there to reach it, but so many hard lines and hoses in the way.

A long neck flat blade screwdriver snaked down to it from the top is tough. And I know these clamps need to be pretty tight or you can have a leak. I have found a flat blade screwdriver just deflects out of the slot once you require extra force to tighten it. Maybe I will play with some extensions and swivel sockets and the appropriate socket to reach that area.

[1991 Corvette ZR-1]

Alright, this will probably be silly to some but I think I found a path. If I remove the frame to bumper brace above the coolant overflow tank, I have a pretty straight shot to the hex head on the clamp with an extension. Just posting pic of how I intend to do it. You can see the silver clamp buried in there in the background.

[secondchance]

Yeah, the factory compression clamp. Good call on the shrinking of the silicone, looks like I am using the smooth hose clamps I have. Back on the creeper and under the car again to have a look. Do you mind posting a picture of your clamp placement on the hose connected to the thermostat housing? I am trying to have the hex head/ flat blade fastener side face out to the passenger side or point toward the overflow tank, so I can snake a tool in there to reach it, but so many hard lines and hoses in the way.

A long neck flat blade screwdriver snaked down to it from the top is tough. And I know these clamps need to be pretty tight or you can have a leak. I have found a flat blade screwdriver just deflects out of the slot once you require extra force to tighten it. Maybe I will play with some extensions and swivel sockets and the appropriate socket to reach that area.

A bit tough to take pics without having the car on a lift. I reach it with car of a lift or on jacks from the bottom and use socket and 1/4" drive ratchet.

[Jagdpanzer]

Here are pics of my thermostat hose connections
1474114743


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[1991 Corvette ZR-1]

Trying to break down the power steering pump and the 1991 FSM has the following on page 3B1-8

DRIVE SHAFT ASM, DRIVE SHAFT SEAL
1. Pump assembly from vehicle
2. Retaining ring (19) from housing (1)
3. Driveshaft (17) and ball bearing assembly (18) from housing.

And that is it. Nothing special noted on the shaft of the PS pump with the bearing pressed on. It will not come out once the retaining ring is removed, because that is where I am at. Pulley off, retaining ring removed and the shaft will pull up and cover the groove where the retaining ring was, but will not go any further. Anyone else run into this issue?

[1991 Corvette ZR-1]

Got it figured out. Found an article on an C4 PS pump rebuild. Jr, the guy that rebuilt another rack for me, used a slide hammer to get the shaft and bearing out. Being the lazy man that I am, I just used a long bolt I had on hand with some washers on it, threaded it into the shaft and the PS pump became the slide hammer. Came out pretty easy.

http://www.superchevy.com/how-to/engines-drivetrain/1804-refresh-your-c4-power-steering-pump-turn-one-systems

[Prez1967]

Glad I stumbled on this thread as Im getting ready to remove my rack as well to send off to TurnOne. Sounds like doing the pump at the same time is the right way to go.

Im rebuilding the suspension and currently looking for upgrading my sway bar bushings "while Im in there". Any suggestions on bushing sources?

[1991 Corvette ZR-1]

Glad I stumbled on this thread as Im getting ready to remove my rack as well to send off to TurnOne. Sounds like doing the pump at the same time is the right way to go.

Im rebuilding the suspension and currently looking for upgrading my sway bar bushings "while Im in there". Any suggestions on bushing sources?

The version I have is Prothane. I rebuilt the whole suspension some time ago with prothane but I kept the poly bushings designed to go onto the rack and pinion. I tossed those in the crate I sent to Turn One to install while they had everything apart. There is also Energy Suspension brand bushings but you probably cannot tell the difference between the two but others can chime in.

I was able to reach the 8mm oil pressure regulator block off plate bolts pretty easy and they were loose, so I tightened those down. There is no way to get to these without raising the engine, according to Marc?s article on his site. Thankfully, with the rack out, I have the room to work on it. I released the wire harness that runs down in front of it and was able to get a 8mm wrench on the one in the front. Once you have your rack out, it could be a good idea to check these if that area looks wet like mine.

The one in the back I could get to once I gently pulled the harness with the O2 and crank sensor all the way out from the front. And that harness is filthy, soaked and caked in oil. Makes sense as it rests right near that block off plate that had a leak. There is another little side project: I will be pulling that harness all the way out to clean.

And then some...

[1991 Corvette ZR-1]

I know this thread is all over the place, but I?m doing little things while the rack is out at Turn One. I cleaned everything up on the engine oil pan and after a few days of sitting, I had a significant leak coming from the low oil sensor that had coated a good portion of the bottom of the pan in just a few days on the stands. So I ordered a low oil sensor from Zip:

https://www.zip-corvette.com/90-92-oil-level-sensor.html?gclid=Cj0KCQiA4feBBhC9ARIsABp_nbVhHtxY 24-hxc39l56noocur1ZXZWJBhZNMSuKadkXIzkq6n_jMfUAaArvkE ALw_wcB

I got this and it?s about 3/4 an inch longer than the stock one. I don?t believe it will interfere with anything. Anyone else using one of these? Ecklers has them as well for nearly $70 but they look like the same type.

[secondchance]

I don?t know. I replaced mine with a version from Jerry?s gasket.
Below would be correct OEM for 91.
https://www.jerrysgaskets.com/sensor-oil-level-91-92-1g2/

[1991 Corvette ZR-1]

I don?t know. I replaced mine with a version from Jerry?s gasket.
Below would be correct OEM for 91.
https://www.jerrysgaskets.com/sensor-oil-level-91-92-1g2/

Thank you for this! I looked but I only saw the 93-95 sensors. Reason I replaced was the plug was soaked inside and the leak appeared to also be coming out from the washer.

[Roadster]

Hello Jamall.....I am also going to change out the hoses on mine....I found a high pressure hose...from the pump to the gear........are you changing the cooler assembly outlet hose from the pump to the cooler... the gear outlet hose assembly from the gear to the cooler.....and the reservoir hose to the pump???
Also did you use metric crow's feet to undo the connections to the gear???
I have the front sway bar out....but don't want to undo the cooler until I undo the gear connections.....any tips will be appreciated.....thanks...:):

[1991 Corvette ZR-1]

Hello Jamall.....I am also going to change out the hoses on mine....I found a high pressure hose...from the pump to the gear........are you changing the cooler assembly outlet hose from the pump to the cooler... the gear outlet hose assembly from the gear to the cooler.....and the reservoir hose to the pump???
Also did you use metric crow's feet to undo the connections to the gear???
I have the front sway bar out....but don't want to undo the cooler until I undo the gear connections.....any tips will be appreciated.....thanks...:):

Hi Tom, the plan was to change as many hoses out as I can. The cooler hose to rack has what looks like a special one time clamp on it. That hose appears to be in good shape, so I plan to keep that one. The others are a little rough. The line that runs from the reservoir to the cooler has 3/8 indicated on the side of it. The U-shaped hose that runs from the pump to reservoir does not have a size indicated. I could probably get by reusing all these hoses but, they are hard as bricks.

For the fittings, I actually used a regular adjustable wrench, I just made sure it was as snug as possible. I will say I tried a crow foot 17mm which was too small and then a 19mm which was too big. So the one crow foot wrench I needed, the 18mm, I lost somewhere. I have a set of line wrenches in standard measurement and they fit on every other fitting on this car, except for the fittings on the rack. 5/8 line wrench will fit great on the high pressure hose fitting going into the pump.

I do not think you can successfully get to all the connections without removing the unit from the engine. The angles you need to get a wrench on fittings and apply leverage pretty much impossible in car. Even with taking some of the side skirt off, at least that was the case for me. And I tried to cheat by gently negotiating the PS assembly into the space the rack was after the rack had been removed and I gave in to do it the right way and drained the coolant.

This is the part I got stuck on. The driver side coolant tube has to be removed along with the elbow hose to make room for pulling the PS assembly up and out. The torx bolts would not budge and one started to show signs of stripping. I hate dealing with them, so I wussed out and sent mine to Pete to get them out. He sent me a pic of the aftermath ...it made me glad I did not double down on trying to remove them.

[Roadster]

Hi Tom, the plan was to change as many hoses out as I can. The cooler hose to rack has what looks like a special one time clamp on it. That hose appears to be in good shape, so I plan to keep that one. The others are a little rough. The line that runs from the reservoir to the cooler has 3/8 indicated on the side of it. The U-shaped hose that runs from the pump to reservoir does not have a size indicated. I could probably get by reusing all these hoses but, they are hard as bricks.

For the fittings, I actually used a regular adjustable wrench, I just made sure it was as snug as possible. I will say I tried a crow foot 17mm which was too small and then a 19mm which was too big. So the one crow foot wrench I needed, the 18mm, I lost somewhere. I have a set of line wrenches in standard measurement and they fit on every other fitting on this car, except for the fittings on the rack. 5/8 line wrench will fit great on the high pressure hose fitting going into the pump.




I do not think you can successfully get to all the connections without removing the unit from the engine. The angles you need to get a wrench on fittings and apply leverage pretty much impossible in car. Even with taking some of the side skirt off, at least that was the case for me. And I tried to cheat by gently negotiating the PS assembly into the space the rack was after the rack had been removed and I gave in to do it the right way and drained the coolant.

This is the part I got stuck on. The driver side coolant tube has to be removed along with the elbow hose to make room for pulling the PS assembly up and out. The torx bolts would not budge and one started to show signs of stripping. I hate dealing with them, so I wussed out and sent mine to Pete to get them out. He sent me a pic of the aftermath ...it made me glad I did not double down on trying to remove them.

Thanks for the reply Jamall....still trying to understand the procedure you did to remove the rack....as mentioned I have the sway bar out and have tons of room because of the radiator and fans are out of the engine compartment.... it seems that if I undo the cooler I will get access to the bolt....but it also seems that at least one hose needs to be disconnected before the rack and cooler can come out.....maybe I am just missing something that is right in front of me.....but it still seems that one connection from the gear needs to be removed before going forward.....also....will not be a problem for me to remove the LS coolant pipe...as I have had mine removed before....so that should not be a problem....again thanks for all of the info....:)

[1991 Corvette ZR-1]

If you are talking about the large bolt securing the rack, I did not bother that one until the cooler was out of the way. The wrench size appears to be 18mm for that fitting going to the rack from the cooler. There are four 10mm bolts holding the cooler on. It is pretty light once you undo the last bolt and I kept mine level taking it off to set aside. You may not have to remove the cooler, just the line from the rack. I removed my cooler because I wanted to also remove and clean the bar assembly the cooler bolts to. As long as you remove the fitting from the rack, you can let the cooler hose hang free.

With the cooler line off the rack along with the high pressure hose coming from the PS pump, the only things left are the main bolt and the smaller two bolts on the passenger side. I pulled the rack out through the driver side. The FSM does not state to remove the cooler but I had already introduced air into the system at that point anyway and with it off I had more free room.

[Roadster]

No not talking about the large bolt.. I am going to remove the cooler...and I already emptied the PS reservoir....
What I need to know is that there are 2 lines attached to the gear that need to be undone...the ones you used the adjustable wrench on...and there is the line that is attached to the cooler with that onetime hose clamp...
How did you go about this...did you undo the cooler and let it hang as you said and then did you remove that hose line with the onetime hose clamp....and then proceed to remove the rack....it appears that I may have to cut a hose....to get the rack out....which would be no biggie.. as I want to replace all of the hoses anyway...
Hope this all makes sense.....lol
Thx...

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[1991 Corvette ZR-1]

No not talking about the large bolt.. I am going to remove the cooler...and I already emptied the PS reservoir....
What I need to know is that there are 2 lines attached to the gear that need to be undone...the ones you used the adjustable wrench on...and there is the line that is attached to the cooler with that onetime hose clamp...
How did you go about this...did you undo the cooler and let it hang as you said and then did you remove that hose line with the onetime hose clamp....and then proceed to remove the rack....it appears that I may have to cut a hose....to get the rack out....which would be no biggie.. as I want to replace all of the hoses anyway...
Hope this all makes sense.....lol
Thx...

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I think I follow. I kept all my hoses intact. The cooler hose that has the unique crimp on it was removed from the rack with a wrench but left attached to the cooler. Before I removed the rack, I unbolted the cooler and set aside.

[1991 Corvette ZR-1]

Hit a snag. There?s a dowel pin that rests in a hole in the bottom of the PS housing. Not sure how this interacts with the pressure plate. There are a few slots in the pressure plate. It is the one part of the breakdown I did not take a picture of. Wondering if anyone who has done this rebuild can chime in? I might have to bug Hans.

[Roadster]

Hit a snag. There?s a dowel pin that rests in a hole in the bottom of the PS housing. Not sure how this interacts with the pressure plate. There are a few slots in the pressure plate. It is the one part of the breakdown I did not take a picture of. Wondering if anyone who has done this rebuild can chime in? I might have to bug Hans.

Hello Jamall......don't know if I'll attempt the PS pump rebuild....I may just cleanup and reuse....but will be following.....
Thank you again for your tips and suggestions.....the rack is out and I just updated my thread with a load of pics.....:):)

[1991 Corvette ZR-1]

Still doing little things while waiting for the steering rack to return. Mainly, I am chasing down leaks. Anyone familiar with this as a leak point on the driver side cylinder head? Some special bolt with what looks like gold tint it. Hoping this is something that can be solved in a simple manner.

[Roadster]

Still doing little things while waiting for the steering rack to return. Mainly, I am chasing down leaks. Anyone familiar with this as a leak point on the driver side cylinder head? Some special bolt with what looks like gold tint it. Hoping this is something that can be solved in a simple manner.

I don't thing that is anything to be concerned about Jamall....I have the same on mine in that area....I think that is the color of the sealant that was used for the heads and cam covers when assembled.....:)

[1991 Corvette ZR-1]

I don't thing that is anything to be concerned about Jamall....I have the same on mine in that area....I think that is the color of the sealant that was used for the heads and cam covers when assembled.....:)

I believe it is leaking around the bolt. I cleaned this whole area up over a week ago and it was all nice and dry. I came out today to find a tiny wet area where the oil has drained onto. I think this might be why it was rough back behind the PS pump. Attached a photo of what it looked like when I removed the PS pump last week.

[A26B]

That is a plug for the hole in the cylinder head used to access the Secondary Cam Timing Chain Guides. There is one on the front of each head.

They are sealed with a dowty washer which usually doesn't leak. You could try tightening it up to see if it might be a little loose.

Here are a couple of links for the Plug/Bolt and the Dowty Washer seal.

https://www.jerrysgaskets.com/plug-secondary-timing-chain-guide-access-new-90-95-7b1/

https://www.jerrysgaskets.com/seal-set-2-chain-guide-access-bolt-90-95-7-5c2/

[1991 Corvette ZR-1]

That is a plug for the hole in the cylinder head used to access the Secondary Cam Timing Chain Guides. There is one on the front of each head.

They are sealed with a dowty washer which usually doesn't leak. You could try tightening it up to see if it might be a little loose.

Here are a couple of links for the Plug/Bolt and the Dowty Washer seal.

https://www.jerrysgaskets.com/plug-secondary-timing-chain-guide-access-new-90-95-7b1/

https://www.jerrysgaskets.com/seal-set-2-chain-guide-access-bolt-90-95-7-5c2/


Thanks, Jerry. I will try and tighten but it sounds like I might get the washers seals to use while I have access. So sounds like I can remove that bolt without issue to install the new washer. Good to know!

[Roadster]

I believe it is leaking around the bolt. I cleaned this whole area up over a week ago and it was all nice and dry. I came out today to find a tiny wet area where the oil has drained onto. I think this might be why it was rough back behind the PS pump. Attached a photo of what it looked like when I removed the PS pump last week.

Was thinking about a slightly different area....my bolt is dry....so hopefully no future leaks.....:)

[1991 Corvette ZR-1]

Alright, guys time to come clean. I chickened out of reusing my factory pump. I was confident in every part of the teardown and rebuild except for that dowel pin in the bottom of the housing. And the FSM provides no instruction on how the pressure plate orients onto it. So I ordered a new pump from Corvette Central specified for the 90-95. There is just one problem: it is NOT for a ZR-1. No threaded holes on the housing and the back is squared off instead of having clearance needed to fit into the recess on the cylinder head as it is bolted to the engine with the bracket. Do not buy from the following.

https://www.corvettecentral.com/c4-84-96/steering/power-steering/90-95-zr1-power-steering-pump-new-564425


I will inform them that it does not fit....who knows if they will actually remove it. So on Monday, I will have to send it back for a refund. May I ask if anyone knows a reputable source that actually sells rebuilt/new PS pumps that will for a fact fit? Before anyone suggests just sending mine to Turn One, I would rather not wait a month to get it back. Good news is the rack came back today. What I MAY do, is give Jr or a tech a call there to discuss the vague rebuild info concerning the dowel pin to pressure plate connection.

[Roadster]

How did the rack rebuild turn our Jamall....was it just the standard rebuilt or were any other parts found that needed replacement???

[1991 Corvette ZR-1]

How did the rack rebuild turn our Jamall....was it just the standard rebuilt or were any other parts found that needed replacement???

It was the standard rebuild. The rack rebuild must have went well because they never called me. I just got an update via email that a shipping number was generated for me. They installed the urethane bushings I sent in my box. One thing, and this is not a big deal, is the aluminum housing was not cleaned. It actually looks like the rack was never opened, except for the new bushings and new dust boot tie straps. I know they ran all the parts through a liquid cleaning process, but not the extra step of blasting the aluminum this time.

If I had to guess, it probably was not Jr who rebuilt my rack this time. I spoke with him over the phone on an 85 rack years ago that had some custom quick ratio parts put into it and he was doing that one personally. When I got that one back, it looked like a brand new rack. Again, not a big deal, as long as it does what it is supposed to. If you or anyone send a rack in, best to include a note that you want that extra cleaning step even if it cost a little extra, if you want that factory fresh look.

[1991 Corvette ZR-1]

Alright, my cynical side says there was at least one person watching me flail around in this thread that knew the answer to my question but was giving me some tough love letting me figure it out. Well I got in contact with someone at Turn One, exchanged some emails with pictures and got my answer. The dimples on the side of the pressure plate which face the front of the housing: either one can be used to place onto the dowel pin recessed into the housing.

Also, the FSM states this with pictures but I?ll also add the pump (part which contains the vanes) has a side that is a smooth bore (counter bore) and a side with teeth. The toothed side of the pump faces the back of the PS pump. Posting this with pictures on the random chance someone else was on the fence about rebuilding their PS pump. It was not hard at all. So it is going back together and going back on the car.

[Roadster]

Alright, my cynical side says there was at least one person watching me flail around in this thread that knew the answer to my question but was giving me some tough love letting me figure it out. Well I got in contact with someone at Turn One, exchanged some emails with pictures and got my answer. The dimples on the side of the pressure plate which face the front of the housing: either one can be used to place onto the dowel pin recessed into the housing.

Also, the FSM states this with pictures but I?ll also add the pump (part which contains the vanes) has a side that is a smooth bore (counter bore) and a side with teeth. The toothed side of the pump faces the back of the PS pump. Posting this with pictures on the random chance someone else was on the fence about rebuilding their PS pump. It was not hard at all. So it is going back together and going back on the car.

So did you do anything specific when you took the pump apart??? still thinking about if I should attempt to do mine...:)

[1991 Corvette ZR-1]

So did you do anything specific when you took the pump apart??? still thinking about if I should attempt to do mine...:)

Nothing too bad. I replaced all the O rings and the bearing on the drive shaft. I used compressed air on the tube coming from the bottom of the pump to pop the rear cover off. The only thing with this is everything else came out with the cover. The vanes are rounded on both sides, so there is no specific way they have go into the pump.

[1991 Corvette ZR-1]

Figured I would share some pictures of what appear to be some dates on the bottom of the plenum. Finally got my thermal past in the mail. Cleaned off the old stuff and found a smiley face in the markings...someone was in a good mood when they were cataloging my plenum back in the day. Any experts feel free to explain what the two dates mean. My guess: the one by the MAP port is the casting date and the date on the module mating pad is when the plenum was pulled for engine assembly.

[1991 Corvette ZR-1]

Just curious for those in the know, what size O rings are used on the pressure line from pump to rack? I had the unfortunate luck of losing my power steering on Easter Sunday....and ironically, I pulled into an empty church parking lot to wait for a flat bed driver. My wife told me she was sorry about it happening and all I could think of was draining coolant. I got the car home and did some investigation to see that the fitting on the high pressure line had backed out and sprayed fluid all over. So, I thought I was clever reaching through the pulley holes with a 16mm line wrench to retighten the fitting.

What I had not counted on was the O ring I placed in a few weeks earlier had gotten pinched apart and let fluid through even after tightening it back down. So with a little more patience, I undid the fitting, pulled the line out and removed the broken O ring and put a new one on. I used a skinny brown Viton ring that matches the original rings that came with it but boy are they puny looking and fragile. Would there be an issue using nitrile rubber rings that are slightly thicker? I got everything back together with the replacement skinny viton ring and it seems to be sealing just fine after a test drive.

To do this, I took a combination 18mm/16mm line wrench, got my angle grinder and cut the 18mm portion off with enough for it to have handle. That way the 16mm will clear the AC lines when loosening/tighten the 16mm fitting. It is probably old news to the veterans on here using this method, but I loathe draining coolant.

[Roadster]

Here are some pics of the "o" rings Jamall....I will try and get a measurement by tomorrow the latest....[emoji16][emoji16]1501415015

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