1990 Oldsmobile Ciera Wagon Pre-mature rear brake lock-up

POPPASHOPPA

MEMBER
1990 OLDSMOBILE CIERA
6 CYL
FWD
AUTOMATIC
126,000 MILES

This has been a chronic problem for about 6 years. The rear brakes grab and lock up under all conditions, even when applied gently. Dangerous when driven on snowy roads. I've replaced the master cylinder, rear shoes, return springs, and turned drums. Mechanic said the cylinders are ok. It seems to clear up for a few days each time someone looks at it, adjusts shoes, cleans, etc, but then the same problem returns.
About 5 years ago a shop told me it had the wrong rear wheel cylinders and he replaced them. No improvement.
I believe Ciera models have 3 brake systems: standard and heavy duty for sedans, and wagon spec. I suspect someone has installed sedan spec components somewhere, but everyone says no.
We don't use the car anymore, but I want to fix it so I can sell it.

5 Replies

BLACKOP555

MECHANIC
10,371 POSTS

Was master cylinder replaced with the proper one?

To me it sounds like your proportioning valves may not be limiting pressure causing a lock up due to low weight in the back when braking. Either that or the front meter valve isnt giving enough pressure to the front brakes.

Are they worn unevenly?

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Wednesday, January 20th, 2010 AT 4:40 PM

POPPASHOPPA

MEMBER
3 POSTS

Master cylinder was replaced due to leak. Problem existed before replacement.

Mechanic substituted another proportioning valve, no improvement. He is old school so he didn't replace my old one.

Your final question intrigues me. Is the front metering valve part of the proportioning valve? If not, this is about the only thing that hasn't been checked. I don't believe my mechanic mentioned anything about it.

I've been online at some other posts and came across one that said to check for sticky parking brake cables. (Parking brakes work and hold). Does this make sense to you?

Thanks for your response

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Wednesday, January 20th, 2010 AT 5:14 PM

BLACKOP555

MECHANIC
10,371 POSTS

P brake cables sticking shouldn't do it due to the fact that it would eventually wear off and if its been 6 years you said! And multiple brake changes. Shouldnt be affecting it at all. If it was dragging the brakes would heat up and not brake in the back. Not grab.

The meter valve may contain the porportioning valve. If it does its considered a combination valve.

Or it could just be a plain metering valve.

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Wednesday, January 20th, 2010 AT 6:41 PM

POPPASHOPPA