caviar emptor

I have a 1992 Chev Cavalier RS, 2-door, 3.1L, V6, A/T, FWD, four sensor ABS (see attached diagram) and the driver side front caliper keeps locking up as if the caliper piston was seized and not releasing.

I have replaced the original caliper with a new caliper and bled the brakes. The brake bleeding was difficult, the brake fluid was barely trickling out even if the brake pedal was pushed in hard. Once the brakes were bled, the same problem (caliper not releasing pressure) reoccurred shortly after the car was started and brakes activated.

I get no ABS or BRAKE warning light.

I suspect this might be an ABS problem. I tried to look up some information. There is no visible identification as to what type of ABS system is on this car. The closest to identifying the ABS module was in this article:

http://www.j-body.org/forums/read.ph...37251&t=137206

The article tells me the Delco VI ABS has been installed in as an option on Saturn, Buick Skylar, Oldsmobile Cutlass Calais and Pontiac Grand Am models, it soon became standard equipment on most General Motors front-wheel drive passenger cars, including Buick Regal and Century, Chevy Impala, Monte Carlo, Malibu, Cavalier and Silhouette.

question: how do i reset the ABS module and test it without using any special tools or scanners?

therewolf

Hello, (again) Caviar Emptor, Welcome to the Chevrolet Forums!

One trick we older shade tree mechanics have learned, (which may or may not work, in this particular case) is to disconnect the battery from the system.
Just unbolt the positive and negative cables, for about 30 minutes. This usually causes the on-board computer to reset, and sometimes also the other systems reset, also.
Another thing to try is to pull the braking, ABS, and any other fuses connected to the braking system for a few minutes, without disconnecting the battery.

Please PM me again, if you have any further issues posting. Enjoy the weekend, and keep us updated on the success of your repair.

caviar emptor

thank you for the "shade tree mechanic" suggestions... unfortunately i did not get to try any of them due to delays getting my questions up on this forum... and by the time my first post with questions was visible, i already ripped the ABS module out of the car and started taking it apart...

As i already mentioned above, i replaced the caliper since i had no reason to think it was anything else. Well, it was not the caliper... so i started searching on this forum and on the web what would be some other reasons why calipers would lock up wheels. Pretty much all sources suggested it was the ABS system so i focused on the ABS module and found sources which reinforced and confirmed my theory and played into my own bias. The post (below) on the jaguar forum totally convinced me it was faulty ABS - stuck ABS valve:

https://www.jaguarforums.com/forum/x...-valve-188478/

based on that ^, i found everything related to my Delco VI ABS system:

the principles of ABS and how it works:
http://faculty.ccbcmd.edu/~smacadof/...m10a_Final.pdf

how to service Delco ABS:
https://www.motor.com/magazinepdfs/062001_04.pdf

and how to bleed Delco VI ABS:
https://www.brakeandfrontend.com/bleeding-abs-systems/

https://www.autozone.com/repairguide...00c152802180b2

Turns out that after many hours of reading, researching, taking ABS out of the car, taking the ABS module apart, cleaning all ABS module components (and not finding any faults... the internals were clean as a whistle) ... and then putting the ABS back in, bleeding all brakes and the ABS module... the problem with brakes locking up persisted.

What was the problem.. you ask? Well, the fault was in 28yo flex brake hose which cost $15 and 20min to replace (Dorman H38905). It appears the hose collapsed internally and the obstruction inside the hose prevented the release of applied brake pressure; thus, the calipers remained clamped and the wheel locked.

so..., that's it... a problem that should've taken no more than 1hr to fix ended up being close to 30hr effort all together... sad

i hope those ABS links ^ help somebody with their ABS trouble...if nothing else

Jiyu

Reading your initial post, that was my first suspicion, blocked hose. Glad you got it fixed. If you replaced the hose with a Dorman item (made in China) rather than an OEM part you may want to rethink that....

caviar emptor

i'll keep an eye on it.. now that i know. needless to say, i was surprised it was the flex hose. i did not think it was possible. i replaced it out of desperation because somebody else mentioned it... to replace the flex hose was not my idea; but it worked...