need brake system help 94 zr-1

[91vettezr1]

Hi
Did a bunch of work on my 1994 zr-1 this past winter. I replaced ,front/rear rotors,pads, drained fluid, Took it out for a drive today for the first time since work was completed. Iimmediately noticed 'SYS" flashing on the LCD readout next to the gas gauge. Light Went out after a few minutes.nO OTHER LIGHHTS LIT ON "DIC" Drove the car for about 1 mile and smelled brakes. stopped the car and it felt like the emergency brake was stuck. I pulled the emergency brake lever but no luck. Turned the car around and it got worse. now the front brakes are locked up and the car barely moved,brake pedal was hard to push in.walked home got some tools ,relieved pressure by opening bleed valves on front calipers. this freed the front brakes up so I could get the car home. anyone have any clue what could be wrong?I just bought the car last year and only put about 100 miles on it since all the repairs so I don't have any history on the vehicle. any help would be appreciated. Have battery charging since I read "sys" could flash due to low battery
thanks
todd

[tomtom72]

Hi Todd, The last time I saw that symptom it was the booster's push rod adjusted out too far......but that was for a system without ASR. I don't know if the same applies to a car w/ASR. I don't see why it would not, but I don't know for sure.

I'm guessing that you tried pulling up on the brake pedal? That is listed in the 90 FSM as a possible cure for "dragging" calipers along with the booster push rod adjustment. Usually it's the rear calipers that drag the worst, or it was on my car. I pulled up on the brake pedal & it cured the issue. Funny part is I can't figure out how or what I did to initiate the problem in the first place. I pulled the master off the booster to check the FSM spec on the push rod and it was good.

Sorry man. I wish I had more insight to share.

Tom

[-=Jeff=-]

TOM,

ASR Is connected through the Accelerator, the hydraulic setup on the brakes is the same when concerning the booster and MC.

Todd was the brake pedal rebounding? I have wonder if the piston in the Master cylinder is stuck. but if it is really hard to depress the pedal then maybe the booster is the problem.

[ZR1dogan]

You didn't say if it was just front or both.

I have had this issue on a motorcycle and later on my Z (front brakes). I learned the root cause and solution on a Honda Interceptor forum (another group of super helpful guys). The problem I had was a plugged hydraulic weep hole in the Master Cylinder. When plugged it won't allow the brake fluid to expand (and return back into the MC reservoir) as the calipers get warm (and hot) while driving. As you noticed it will only get worse until you either bleed the calipers or let the car sit long enough to cool the calipers and fluid.

You can get a new MC or try what I have done. Note that I am speeking from 3+ year old memory and mine is a '94 (I think the MCs are the same), so this is the concept but the exact details may be a little off.

Take off the MC cap and lower the fluid in the MC as low as it takes to be able to see to the bottom. Near the back is where the weep hole is. Obtain a long thin needle (I tried sharpening something long - it doesn't work - not thin enough). Hold the needle in a set of needle nosed pliers (I taped the pliers shut on the needle, so that the needle wouldn't fall out of the jaws if I accidentally let off compression on the handles). From the top, with the needle in the pliers, feel for where the weep hole is (where the needle feels like it can be pushed in). Push it in and see if it works. It did for me.

Good Luck - Let us know if this does it.

Robin
'94 Dark Red - Almost Stock
'94 Adm Blue - Not Stock

[91vettezr1]

Originally Posted by ZR1dogan

You didn't say if it was just front or both.

I have had this issue on a motorcycle and later on my Z (front brakes). I learned the root cause and solution on a Honda Interceptor forum (another group of super helpful guys). The problem I had was a plugged hydraulic weep hole in the Master Cylinder. When plugged it won't allow the brake fluid to expand (and return back into the MC reservoir) as the calipers get warm (and hot) while driving. As you noticed it will only get worse until you either bleed the calipers or let the car sit long enough to cool the calipers and fluid.

You can get a new MC or try what I have done. Note that I am speeking from 3+ year old memory and mine is a '94 (I think the MCs are the same), so this is the concept but the exact details may be a little off.

Take off the MC cap and lower the fluid in the MC as low as it takes to be able to see to the bottom. Near the back is where the weep hole is. Obtain a long thin needle (I tried sharpening something long - it doesn't work - not thin enough). Hold the needle in a set of needle nosed pliers (I taped the pliers shut on the needle, so that the needle wouldn't fall out of the jaws if I accidentally let off compression on the handles). From the top, with the needle in the pliers, feel for where the weep hole is (where the needle feels like it can be pushed in). Push it in and see if it works. It did for me.

Good Luck - Let us know if this does it.

Robin
'94 Dark Red - Almost Stock
'94 Adm Blue - Not Stock

hi
it was both front and back. i am going to replace the master cylinder next weekend. most people say it's the master
will keep u posted
thanks
todd