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Brake pedal slow return

19051 Views 8 Replies 5 Participants Last post by  RaiRai
I've had this condition for years, now let's see your opinion...
So, in drive the problem comes basically only on slippery surface; when you release the brake pedal, wheels are still locked for a while and you can't control the ride like you should.. My car has passed inspections several times with this cond, brake forces themselves are good.
What's new:
front - calipers, pads, brake hoses
rear - calipers, rotors, rearmost lines, rearmost hoses.

Preliminary tests reveal that if I grap the pedal with my hand and pull it back, so do the brakes.
Between the lines from main cylinder to rear and rearmost lines there are hoses. Could those be plugged and cause this problem? Something with brake booster / vacuum things? Thanks already.
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Ok. If I'm removing the master cylinder, what are the odds the connected lines will not be damaged?
Just replaced the master cylinder and did all the bleeding, naturally from all the calipers as well. All went smoothly, thanks for your advices. Result: NO CHANGE whatsoever. Bit frustrated as I've replaced almost all the brake components and still a word describing overall braking performance of this ultimate 4-wheel vented disc setup is: poor.
Yeah passed another inspection with the condition and braking forces are "just fine". Brake feel is lousy, spongeous. I can't lock up the wheels on asphalt no matter how hard I press. Just tested so that removed vacuum from brake booster; braking performance is very very poor (as expected) but the pedal seems to return normally. Without booster the pedal feels much harder, as IMO it should be with booster as well.
Ideas? I'd quess something with the brake booster or some related valve, or something else... (I'm saving the original aluminium master cylinder as it probably works perfectly well).
As a note I just drove again my mother's 1989 5-series BMW with 390 tkm. Those brakes feel about 10 times better and reliable compared to my LeBaron, a good reference. Those are small 4-wheel solid discs.
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While bleeding the brakes today, noticed something which is probably related to this. When I press the pedal to the metal (with lots of air in the system, engine off), there is some jamming in the pedal return at some point before it is all returned. This can't be from the master cylinder spring as the master cylinder was replaced. I think there is a spring in the booster as well. Did not check yet inside the car behind the pedal if there is something... Could it be anything else anymore than the booster? And btw the booster valve-thing where the vac hoses go in the eng. compt. is new as well. All the flex hoses have been now replaced as well.
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