1992-1999 Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's and Buick Lesabres Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

brake trouble

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Old 01-27-2005, 05:53 PM
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Default brake trouble

Well, I had my new KYB struts put on today at the dealer, and a soon as I left the lot, the front brakes started squealing. When I pulled over and checked them, the calipers were stuck in the braking position, and the rotors were very hot. The brakes didn't make any noise at all during the test drive at the dealership though. Any thoughts on what the problem could be? Could it be a plugged brake line that is causing the car to ride the brakes?
Old 01-27-2005, 06:14 PM
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Did you check both sides, or is just one side sticking? If this just happened after the struts were diddled with, and if it is just one caliper sticking, I might suspect that one of your flexible brake hoses suffered internal damage from being twisted, pulled stretched too far, etc. during this work. Doesn't show on the outside, but the inside walls of the hose can get torn and act like a check valve, holding some pressure on the caliper piston after you release the pedal. This problem drove me crazy on an '84 GMC pickup.

I can't think of anything else that might be related to strut replacement that would cause your brakes to hang up?

It may just be a piston stuck in a bore of the caliper. Doesn't seem like strut work should affect that.

If both brakes are sticking, gotta look elsewhere, upstream.
Old 01-27-2005, 07:39 PM
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Both sides are sticking. I played around with the brakes for a bit, and now I am pretty sure that the brake lines are clogged and have air in them.
Old 01-28-2005, 02:35 AM
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It just doesn't seem likely that most mechanical problems that would prevent a caliper from releasing would occur on both sides simultaneously. Not impossible, but not likely. This would include stuff like a bad hose, sticking piston, even bad fluid. So I'm thinking it points to something upstream like the master cylinder or the brake booster.

My factory service manual is for 1992, so I am not sure how relevent these items are to your '96; but here is what it lists as the most likely causes under: Brakes drag -

Brake pedal linkage interference or binding
(Is something preventing the pedal from returning all the way up?)
Improperly adjusted master cylinder push rod
(not likely in your case)
Weak or incorrect brake shoe retention springs
(rear brake reference)
Improperly adjusted stop lamp switches
(these might be preventing the pedal from returning all the way up)

Other less likely causes:

Contaminated or improper brake fluid
Power booster damaged
Missing or loose brake assembly attachments
Incorrect rear brake adjustment
Restricted brake fluid passage
Improperly adjusted parking brake
Sticking wheel cylinder or caliper piston
Faulty proportioner valve
(I am not positive, but I don't think this would cause both fronts to stick, as there is one valve between each caliper and opposite rear wheel)

So, It is possible that bleeding the brakes might help by flushing out any contaminated fluid that might have been stirred up when your struts were done. It will also remove air from the system. Air in the lines should result in a spongy pedal. For a description of how to bleed your brakes, go here: http://www.bonnevilleclub.com/forum/...009&highlight=
You will want to read the entire thread.

[edit] Fuddyduddy made an excellent suggestion for bleeding brakes easily and effectively by yourself - install a set of speed-bleeders. Ask at your auto parts store - I think a set of four is about $10-12.

Now, if an ABS fault is causing your problem, you will need to find more knowledgable help - and probably someone with a '96 FSM too.
Old 01-28-2005, 02:48 AM
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Just a thought: if your car was braking fine before the dealer did this work and now isn't, it seems reasonable to ask the dealer if they had to disconnect some brake lines to do the strut work, or otherwise needed to work with the brake system components. If they don't offer to fix it, they might at least give you a diagnosis.
Old 01-28-2005, 09:00 AM
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Thanks. The brakes do feel spongy, but when you push them in, the pressure builds up very fast. I'm going to take the car to the shop that installed the brakes a few weeks ago, since they are still under warranty there. I already know that the new pads are going to have to be replaced, I just hope that the dragging didn't warp the new rotors also.
Old 01-28-2005, 10:31 AM
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Let us know what was causing the problem. Some of us are curious. :?:
Old 01-28-2005, 05:38 PM
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I took my car to the shop today, and they told me that when the dealer put the struts on, they pushed the backing plate on both brake assemblies into the rotors. The shop bent the backing plate off of the rotors, and the brakes worked fine. The backing plate is part of the ABS unit though, so I have to take it to the dealer so they can put new ones on there.
Old 01-28-2005, 06:42 PM
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Jeez, high quality work, huh? Thanks for letting us know.
Old 01-28-2005, 06:44 PM
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With all brakes aside, how do the struts feel?


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