Rear calliper piston not retracting when handbrake released

[kilmo_172cup]

I have a 53reg Clio 172 Cup. Recently I found the handbrake not holding my car very well on inclines. I also noticed that the drivers-side rear wheel started to get very warm after relatively short journeys.

I discovered that the piston in the drivers-side rear calliper fails to retract from the brake pads when the handbrake is released. If I use a screwdriver to lever back the housing where the brake pads are located, the piston pushes back in slightly and the wheel once again becomes free but this has to be done every time otherwise the pads are in constant contact with the discs.

In addition, even with the handbrake fully on, I am able to move the drivers-side rear wheel with my hands, whereas the passenger rear wheel remains solid, so it would appear that there is also a problem with the piston not pushing out to hold the wheel tightly enough.

On the other hand, the foot brake holds the drivers-side rear wheel solid and retracts the piston as it should, so it would only appear to be a problem with the handbrake part of the calliper that pushes out and, in particular, retracts the piston when the handbrake is released.

Does anyone know if the calliper/piston can be fixed at all? If not, can the handbrake part of the calliper (that is, the part that is causing the piston not to push out and retract correctly) be replaced separately, as the foot pedal operates the piston perfectly or will it require a whole new calliper unit?

Any help would be much appreciated.

 

[gtruk]

well ive worked on other calipers, and most are servicable. The piston may just need regreasing. Also to be sounds like your hand brake cable isnt engaging both brakes so you might want to take it to a garage to be on the safe side and get it fixed once and for all

 

[kilmo_172cup]

I have detached both handbrake cables and operated the handbrake lever on both callipers by hand to simulate the handbrake being pulled and the cables becoming taught.

The drivers-side rear calliper handbrake lever can be easily operated by hand, with the piston pushing out but not visibly retracting as the passenger-side rear calliper piston does. Whereas, the passenger-side rear calliper (the one that works fine) is a great deal more stiff to operate and requires a mole clamp to turn by hand.

So it would appear that just the handbrake part of the calliper is at fault and not the actual handbrake cable, as the problem remains when the handbrake cables have been detached.

Is it possible that removing and regreasing the piston could solve this problem? How difficult is it to reassemble, as I have been told that its almost impossible to realign the rings back in piston?

 

[kilmo_172cup]

Anyone???