HELP! Spider failed MOT on rear brakes. Compensator Valve?
My spider failed it's MOT (and subsequent retest) on the rear brakes.
Before the MOT I replaced the rear brake pads. I had a lot of trouble winding in the LHS piston, but in the end both sides failed equally. I took the car for an intense braking session over about 10 miles, but maybe wasn't enough to bed in. The garage seems to think that it is more fundamental than this.
As for the handbrake, readjusted it, it held and one side shot up in efficiency, but overall the handbrake is still only 13% when it needs to be 16% to pass. The fact that the handbrake is better but the rear brakes aren't, makes me think this isn't sticking callipers...
Could it be that the rear compensator valve is stuck and if so this would mean that both sides are low on pressure and won't actuate? Where is this valve and is there anything I can do to diagnose it or repair it?
Brake feel through the pedal seems pretty good and the front brakes are excellent! I have been told that if I get it in before a week Friday (21st feb) then the car can be retested and the first retest wasn't recorded.
Your help will be so greatly appreciated!