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I have what can only be described as an intermittant brake fault!
This first raised it's ugly head at sva where my rear brake lines were kept pressurised thus binding the rear brakes.
I first thought it was too much pre-load on the master cylinder as when I backed this off it dissapeared howeverit has since come back and ther is no pre-load on the piston now at all.
Once the car has been driven for about 30 mins it normally corrects itself so I am now thinking that the master cylinder is the problem.
Before I buy a new one does anyone have any other thoughts on what it might be?
The binding on the rear line does not apply the brakes fully but probably about 35% on! car won't accelerate in 5th and 6th when it happens
Also the Rover rear calipers have a known problem with the piston locking up. If your using the Rover ones, let me know and I can dig out a guide on sorting them out.
Is it the service brake or parking brake that is causing the problem?...I have known of rear pad application due to handbrake cable sticking or being put under tension as the suspension moves...
Other than this...I've not come across the problem.
sorry I probably should have included the fact that pedal feel is normal but when the issue arises the pedal is rock solid so there is no issue with the handbrake.
The rear line defo gets pressurised I'm wondering about seals inside the master cylinder or is it possible with a bias fitted in front line (intermittant malfunction) for maybe feedback through master and locking pressure into the rear line?
Craig
ps the issue is never there from cold only when car has been driven for a few minutes then seems to clear after 30-40 mins
I had the exact same problem on a 1991 Vauxhall Astra... It was nearly 8 years ago I owned that car but I'm 99% certain it was a faulty front calliper
As the brakes heated up so the pedel travel reduced until the brakes started to bind
The brakes fitted to low cost production cars are always rubbish... I think I changed the Astra's front collipers for those off a Cavalier SRi which a much better design. Shame it's not quite as easy with the rears because these seem to be the same on all models?