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Strange feeling in brakepedal
marcotuinenburg - 17/9/06 at 06:13 PM

Hi,

I am hoping you guys know what's going on inside my brakesystem.
Whem i did a testdrive yesterday i felt i couldn't brake very hard.
The first time whem i'm trying to brake the pedal feels hard but when i hold it it starts to soften and i can push it further in. Untill it reaches the end.
When i let the pedal go it comes very slowly back to it's original position.
Could it be air in the system or is there something wrong with my mastercilinder or both ???
Please any suggestions

MikeRJ - 17/9/06 at 06:40 PM

That points to a leak in the system. If there are no obvious signs of fluid from inside the wheels it's most likely the master cylinder. Is it new or did you fit one from a donor car?

zetec7 - 17/9/06 at 07:03 PM

Has it been sitting for some time? It only takes a small bit of grunge to cause problems in the master cylinder. The slow-returning pedal points to some contaminant in the master cylinder which isn't allowing the piston to return properly, the hard initial pedal points to grunge in the outlet ports of the master cylinder not allowing fluid out, and the gradually-softening pedal points to fluid leaking past the piston seals. I'd rebuild the master cylinder with a seal kit (or get a ready-rebuilt unit - they're not expensive), flush the system with fresh fluid, and bleed the system well. That should fix it!

marcotuinenburg - 17/9/06 at 07:09 PM

It's an old mastercilinder and it did sit for a few years, i will check for other leaks this week and get a new master cilinder.
Thanks, Marco

Catpuss - 17/9/06 at 08:40 PM

My tintop astra was like that. Hard push then softened up. Both rear slaves have their seals fail. From the state of them they had both failed recently at the same time.

Got them done and was fortunate as I had to do an emergency stop on an A road as a HGV decided that it didn't want to wait before pulling out across me.

britishtrident - 18/9/06 at 07:32 AM

Check all the pipe unions for a tiny fluid leak under pressure.

dr-fastlane - 22/9/06 at 03:10 PM

I have had the same problem. No leaks at the outside of the brakesystem. Replaces the MC for an new one and the problem was solved.

t.j. - 22/9/06 at 05:32 PM

Je hoofdremcilinder is waarschijnlijk defect.

Controleer eerst even of hij wel geheel terugkomt in de nul-stand. ivm onluchten


For our English folks:

Prob. Is the Mastercilindre broke. It has internal leaks, which allows the brakefluid to return.

[Edited on 22/9/06 by t.j.]