Rear brakes excessively grabbing - MOT fail

[bradbassett]

Hello all,

My girlfriends car (96 Corsa 1.4LS) has failed its mot due to the rear brakes excessively grabbing, although the garage I've taken it to aren't quite sure why. Initially with this problem they said they would go about changing either an adjustor or invertor (I've managed to forget the name of the part they said it was, but its supposedly whatever adjusts / controls the amount of pressure that gets applied to the front and rear brakes, and is located somewhere on the rear axle??) but none of their suppliers do this and it is a Vauxhall only part.

The rear cylinders were replaced 18 months ago, but not the shoes at the same time and we've had problems when taking the hand brake off, that the car won't budge and the rear brakes appear to be locked, and it takes a bit of rocking the car backwards and forwards to get the wheels free, although it hasn't done this for a while. So the garage have taken apart the rear brakes to have a look at this and cleaned up all the dust that was in there and checked that all over to make sure its working as it should, but it still grabs excessively on the rear brakes when going to brake.

Has anyone else had this problem at all or have any suggestions as to what could be causing this / what needs replacing.

Any suggestions would be greatly received.

Thanks very much.

Brad

[Octane2097]

has it been lowerd?
tend to find if it has then it affects the rear brake pressure compensator and would need adjusting
or the valve its self could be brokem (most likely the spring)
the valve is located under the car infront of the right rear wheel and should be set so that the slack on the spring has just been taken up
if the spring is under serious tension then chances are its letting too much braking force thu to the rear wheels.