Power steering Pump Question.

[Ccmano]

I’m working on a power steering issue on my car. I’m finding ZR-1 specific power steering pumps impossible to find at the local parts stores. Rock Auto has one, it’s an aluminum bodied pump not the OEM steel. L98 pumps are plentiful.

I have physically compared the L98 pump and the ZR-1 pumps. They are identical in every dimension. The only difference I can find is the supply hose nipple. Straight on the L98 Pump, slight elbow on the ZR-1 pump. The L98 pump bolts up the the LT5 perfectly. Tried it on the spare engine I have.

My question is this, are these actually identical? The racks they utilize are identical and interchangeable so I would imagine the pump output to be the same. Is anyone aware of any other differences, rotating in the opposite direction or some such?

Thanks
H
:cheers:

[Dynomite]

I have both L98 and LT5 so this is interesting :thumbsup:

The L98 Power steering Pulley rides on outside of belt (smooth side) and rotates counter clockwise looking from front.

The LT5 Power steering Pulley rides on inside of belt (grooved side) and rotates clockwise looking from front.

Did not measure diameter of pulleys since they are not interchangeable.
The oil reservoirs are different as L98 is separate and LT5 is behind pulley.

If this sounds strange......I will look again as I just fired up both engines.
I have no modifications regarding Power steering on either Corvette engine (1990 L98 and 1991 LT5) :cheers:

Corvette Central has Aluminum Body Power Steering pumps (ZR-1) for $145.
https://www.corvettecentral.com/c4-84-96/steering/power-steering/90-95-zr1-power-steering-pump-new-564425?returnurl=%2fc4-84-96%2fsteering%2fpower-steering%2f%3fcount%3d18

I did see an advertisement for rebuilt Corvette Power Steering Pumps without the ZR-1 Option.

Rebuilt ZR-1 Power Steering Pumps for $88 (Free Shipping).
https://www.ebay.com/i/253510303250?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=253510303250&targetid=541454196892&device=c&mktype=pla&googleloc=9031853&poi=&campaignid=1881946470&mkgroupid=74094014870&rlsatarget=pla-541454196892&abcId=1139336&merchantid=114724799&gclid=EAIaIQobChMIu92P9Mmp5AIVUxitBh0LYACcEAQYBSAB EgKwMvD_BwE

Search Ebay (ZR-1 Corvette Power Steering Pump) and you will find several used ZR-1 Power Steering Pumps.

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[secondchance]

Might be wothwhile to talk to a tech with a turn One.
https://www.turnone-steering.com/

I had my rack rebuilt these guys and they did an outstanding job.

[Paul Workman]

:happy1:

[Ccmano]

Thanks Cliff, looks like it does rotate in the opposite direction. Answers that question.
H
:cheers:

[gbrtng]

NAPA used to stock rebuilts ... apparently used on other GM vehicles because there was one at the local store in Naperville. NAPA did not have a way to cross reference to the other applications however. Probably a Geo or Malibu ...

[Ccmano]

So here’s an update. Internet/Ebay sellers were all out of stock, even though they were running current ads. I suspect many used the same source. None of the local parts outlets have stock including NAPA.

This part is IMPORTANT! The only pump currently available is the one sold by RockAuto and others manufactured by the LARES company in Minnesota. You can buy them new or rebuilt. THEY DONT FIT! The reason the don’t fit is because the two lateral mounting holes (of three) are not threaded and are too large on their pumps. I ordered one from RockAuto, opened the package and found the holes unthreaded and too large. I called LARES and the nice folks there told me it was a mistake, to send it back and another would be sent. I did that, got the pump and it was identical to the first. Called the nice folks at LARES back (they really are nice), this time they told me that based on the GM specs they use the holes are not threaded. WRONG! I’ve done a bunch of these, all three holes are threaded. That second pump is going back too. No new pump coming.

So at present if you need a PS pump you will need to either send it to TurnOne or LARES and have it rebuilt or rebuild it yourself. Mine was a bad bearing so I’m rebuilding it myself. A complete kit is less then $20.

As previously noted these pumps are unique in that the rotate clockwise (when viewed from the front) whereas L98 pumps rotate counterclockwise. Looks like we may be adding another part to the scarcity list.
H
:cheers:

https://farm66.staticflickr.com/65535/48762378501_2245f74647_c.jpg (https://flic.kr/p/2hhXWgP)

https://farm66.staticflickr.com/65535/48762378541_1d6eb433b2_c.jpg (https://flic.kr/p/2hhXWhv)

[gbrtng]

Is there any possibility of using thread inserts?

[Ccmano]

Is there any possibility of using thread inserts?



I suppose, probably have to redrill, thread and use a helicoil or such of appropriate size. Could affect warranty though.
H


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[A26B]

......................................So at present if you need a PS pump you will need to either send it to TurnOne or LARES and have it rebuilt or rebuild it yourself. Mine was a bad bearing so I’m rebuilding it myself. A complete kit is less then $20........................................
H
:cheers:

Great job doing all the research to be able to solve this parts "NLA" delimma. Do you have a source & PN for the "complete rebuild kit?

Thanks Hans!

[Ccmano]

Great job doing all the research to be able to solve this parts "NLA" delimma. Do you have a source & PN for the "complete rebuild kit?

Thanks Hans!

The kit is from “AutoPartsGeek” via EBay, $18.96 Shipped, a US company, Parts are from USA, Mexico and Taiwan.
H

https://farm66.staticflickr.com/65535/48762378491_9e84d6beb3_c.jpg (https://flic.kr/p/2hhXWgD)

https://farm66.staticflickr.com/65535/48762378506_6ae95e5ef0_c.jpg (https://flic.kr/p/2hhXWgU)

Five sources of ZR1 (90'-95' ZR-1) Power Steering Repair Kits are provided each having 7 parts (one extra "O" ring in each kit over that shown in Kit # 8401401).

Edelmann Power Steering Repair Kit 73198ZF (https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F39 2403103710)

Gates Power Steering Repair Kit 1819XP (https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F39 2398330874)

Sunsong Power Steering Repair Kit 8401344 (https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F16 3873307628)

Edlemann Power Steering Repair Kit 8561 (https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F30 2498343097)

Sunsong Power Steering Repair Kit 8401344 (https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F11 3893577019)[/QUOTE]

[Ccmano]

So I replaced the front bearing and seal. Works like a champ! The shaft and bearing are held in from the front with a C-clip. Once the C-clip is removed the shaft and bearing pops out with little effort. This exposes the front seal. The seal is a press fit, some judicious prying and it popped out. The new seal went in with an appropriately sized socket to gently hammer it in. The bearing has to be removed from the shaft with a press. The clearance from the inner race to the shoulder of the shaft has to be measured and noted before disassembly so that the new bearing can be pressed to the same clearance. A half inch drive long socket of the appropriate size to press from the inner race did the trick to press the bearing off. Similarly a socket to support the inner race of the new bearing is used when pressing the shaft on to the bearing, noting the clearance to the shoulder of the shaft. Once together the shaft and bearing pop back in and the C-clip is replace to hold it together. That’s it. The rear seals can be accessed from the other side. Mine wasn’t leaking so I left it alone. Looks like the rebuild is pretty straight forward. I think I’ll be rebuilding these moving forward. They usually just leak or have a bad bearing. BTW the full rebuild process is written up in the FSM under “Unit Repair” of the Power Steering Pump.
H
:cheers:

https://farm66.staticflickr.com/65535/48762059333_c6c155c823_c.jpg (https://flic.kr/p/2hhWioV)

https://farm66.staticflickr.com/65535/48762378706_80c0161823_c.jpg (https://flic.kr/p/2hhXWkm)

https://farm66.staticflickr.com/65535/48762378691_c132cc50b0_c.jpg (https://flic.kr/p/2hhXWk6)

https://farm66.staticflickr.com/65535/48762378501_2245f74647_c.jpg (https://flic.kr/p/2hhXWgP)

[jss06c6]

Looks like I'll be adding this to my parts inventory! Thanks Hans!

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[Dynomite]

In -Solutions- Post #5 under Steering..........Power Steering Pump Repair Kit (http://zr1.net/forum/showthread.php?p=298797)

[klork]

PSC motorsports might be another choice in getting the pumps rebuild. They do high quality pumps for off road and could probably rebuild these pumps.

[jss06c6]

Ordered one for the parts bin yesterday Hans. Thanks!!

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[Roadster]

Hans, question for you. Is there a difference in the different rebuild kits I am listing? It seems like one kit has different part added, or they are just using a specific generic pic that they use!!!
Thanks for any info, Tom

Sunsong 8401401.....the kit you purchased

Edelmann 8561.....another one I found

Sunsong 8401344....another Sunsong that appears to have a different part

[Ccmano]

Good question Tom, There are basically three versions of the same pump used on the C4 line from 84 to 96 corresponding to the 3 engines used. L98, LT1/LT4 and LT5. The differences between the L98 and LT5 are documented in this thread. Not sure how the LT1 version differs.

Looks like between the two Sunsong products one has the bearing and the other does not.
The Edelmann appears to have the bearing as well.

From my observations the internals are all the same with the exception of the vane direction that determines direction of rotation.

H
:cheers:

[Roadster]

Good question Tom, There are basically three versions of the same pump used on the C4 line from 84 to 96 corresponding to the 3 engines used. L98, LT1/LT4 and LT5. The differences between the L98 and LT5 are documented in this thread. Not sure how the LT1 version differs.

Looks like between the two Sunsong products one has the bearing and the other does not.
The Edelmann appears to have the bearing as well.

From my observations the internals are all the same with the exception of the vane direction that determines direction of rotation.

H
:cheers:

Yes and a great documentation that you did Hans. But if you look again at all 3 kits.....the one you purchased Sunsong 8401401 shows on ebay that it contains 5 parts from the pic shown, while the kit you purchased shows 6 parts.
The Edelmann 8561 shows 7 parts and there is one part that looks different from the part shown in the 8401401 kit that you used.
The Sunsong 8401344 also shows the same 7 parts as the Edelmann 8561 mentioned above, and again there is one part in there that differs from the one in the 8401401 kit.
Not having the schematic handy, I am just curious as why there is a difference in that one part and the 2 latter kits each have 7 parts compared to 6 parts in your kit. And each of the 3 kits listed say the ZR-1 pump is compatible with each kit.
Will have to get the FSM out and check the schematic.
Again, your documentation is great and now I am deciding on whether to go ahead since the entire front cooling system is out of my 94 and just redo the pump as you did. Have to check and see if there are any leaks, at least if I do decide to proceed, there is plenty of room to get it done.:)

[32ValveGuy]

Thanks Hans, just ordered a repair kit for my spare parts inventory

[Ccmano]

Here are a few links off eBay both Sunsong and Edelmann. All these include the bearing.

Since I only did the bearing and front seal I’m not sure how the rear seals differ. I don’t have another pump handy otherwise I’d pull one apart and document the entire rebuild.
H
:cheers:

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F39 2403103710

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F39 2398330874

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F16 3873307628

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F30 2498343097

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F11 3893577019

[Roadster]

Hans, they all pretty much are the same kits from what I found....but just branded under different names....think I'll get one of them for spare or just pull it apart as mentioned before....at least we have some additional choices...:)

[jss06c6]

Ordered one for the parts bin yesterday Hans. Thanks!!

Sent from my SM-G950U using ZR-1 Net Registry mobile app (http://r.tapatalk.com/byo?rid=90383)Well, they came back with out of stock and refunded my order. Dang!

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[Ccmano]

Well, they came back with out of stock and refunded my order. Dang!

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Steve, just posted a list of all available kits on eBay at post #11 in this thread.
H
:cheers: