Howdy, my 92 still seems to want to pull to the right when I brake hard. I had it aligned and put new brakes, rotors, and brake lines in. I broke the pads in and bled everything out. I was haulin down the autobahn and sure hell some dumb @ss cut out in front of me like always and I was forced to slam on the brakes, They didn’t lock up and the did stop well until the "SERVICE ASR AND SERVICE ABS" lights came on and the peddle seemed to go a little soft. GREAT! I thought I blew a line somewhere. When I got her home there was not leaking brake fluid and one I shut it off and started it back up the lights were out. You guys think it will be alright? I think that the problem with it still pulling when I brake will be solved when I rebuild the calipers. Any thoughts?

Also sometimes when acceleration fast and the RPMs go up past 4500 the ASR will go active and push my foot off the accelerator. What’s with that?

 

anybody?

 

Only thing left is the calipers.
Mike

 

I guess what I am asking is what causes the SERVICE ASR and SERVICE ABS lights to come on and stayed on until I shut it down, They stayed off when I restarted it. I hit the brakes pretty hard going pretty fast. I didnt see any brake fluid leaking anywhere when I parked it. Just wondering if there is something that I should check. Usually when a Service something light comes on something went wrong. Hell even my parking brake light came on for a second when I hit the brakes. Any Ideas would make me feel a hell of a lot better for the next time I take my car out. Last thing I need a total brake lost going down the Road. Thanks for any thoughts

 

....so take this with some reservation.

First, the pull to one side while braking usually means that the caliper opposite the pull is not clamping enough. Causes: air in one caliper, sticky pistons, stuck slider pins or other bad caliper hardware. Our C4's use sliding calipers so the hdw has to be up to the mark.

Electronic issues with the "service ASR & ABS" lights. The wheel sensors could be bad or not making a good connection or not giving the proper signal. Best to use a scan tool with the software specific to the system to see if any DTC's have been set. I also think that if the proper soft ware is used the scanner can "test" those systems to be sure that all the parts function properly. I'm not sure about this but I'll throw it out anyway; if the system has any trapped air in the ABS module (pump) you will get the service lights and you could also get the parking brake/brake pressure warning light to light up. On that note, did you replace or rebuild the master cylinder or change out the brake bias spring? The pressure switch has to be put back in properly. Also if the M/C has air in it that light will come on, I think. I just did some brake work on my 90 so I'm trying to remember when the brake warning/ parking brake light came on...it stinks to be forgetfull! Anyway that light will come on in response to low hydraulic pressure.

Sorry that's about the extent of my knowledge.:o


Tom

 

I did not replace the master cylinder or spring but I did adjust the brake boost out a couple turns a few days back. ( which did seem to help on the braking). So the parking brake light is also a warning light? That I didn't know. Not a surprise that it came on then. I looked like this when I had to slam on my braked from 140 to 70 and then as the lights came on. I guess Ill order the brake caliper rebuild kits and hope that will take care of the pulling problem. As far as the lights. Maybe Ill have the repair shop hook it up to there test machine and see what that says.

Thanks for your reply.

 

On that adjusting of the booster push rod, I've a 90 so again take my comment with that in mind. In my Helm FSM it gives specific insructions about how far out the booster push rod must be. I have a different booster as I own a ZR-1 so I'm not saying you did anything incorrect. I rarely read past the "Vin # J" sections unless it's a common procedure for shared components.

I just thought that this info might be of some use. I don't know if the push rod adjustment is critical to your application as it is to my application.


Tom

 

I just got my helm service manual the other day. Ill look to see what it says. I haven't had time to open it up yet. BTW I wish I had A ZR-1. Damn that engine looks sweet!

 

I don't know the solution, but I recently developed almost the exact same problem on my '92. Mine pulls to the left under hard braking, and the service asr and service abs lights come on, then go out when I shut down and restart. Then eventually back on next time I drive. Also, the "brake" light comes on and off sometimes.

I haven't diagnosed it yet, but I'll be interested to see what you find, since it sounds so similar. I wonder if the pulling and fault codes are related, since we both seem to have both problems. I plan on going through the service manual sometime this week.

 

Thanks for the kudo's on my baby! Yea, I like it just fine!

I'm not being sarcastic but yes do use the Helm FSM on this one. There is a large difference as my 90 does not have ASR integrated with the ABS. Those are advances that came after the 90 model yr so my FSM has nothing for the newer integrated ABS/ASR system....I know that they are a "coupled" system but that's all I know for sure. The causes for malfunction may be a bit more complicated than those that apply to my system as it is a stand alone ABS with no ASR.

Of this point I'm fairly certain. Upon start up my ECM puts the ABS thru a diagnostic test. If it checks out okay then no lights and DTC's are set, the Service ABS and the Brake lights are dark. If the system has a hard failure then a DTC is set and the Service ABS light comes on. If there is air in the system there is no way that I can see that the ECM would know. By extension if air is trapped in the ABS pump it would only evidence itself when the ABS was activated as the brake sys works in normal mode by by-passing the ABS pump. Again, any air trapped in the ABS pump would show up as a loss in hydraulic pressure and the Brake light would illuminate but only if the ABS sys was activated. The air might leave the ABS pump and wind up someplace else in the system. If the air stopped at a caliper then that caliper would suffer a lack of clamping force and cause a pull. MAYBE, but I could be waaaay off base in my thinking.

I know that for my yr ZR-1 when ever the system needs to be bleed without using a TECH1-A scan tool our registry notes indicate that the system is to be bleed manually and then the car driven so to activate the ABS system and then re-bleed to eliminate the air that could have been trapped in the pump. The Tech1-A scan tool has the software to "cycle" the ABS pump without moving the car. I do not know if that applies to the integrated ABS/ASR systems though.:o


Tom