brakes

[aide47]

hope someone can help with advice please.just replaced handbrake cable and rear brake hoses for mot.on completion we cannot get a pedal when bleeding.infact we cant get any air or fluid through bleed nipples.have been advised we may have damaged master cylinder but if i squeeze the rear hoses with grips we get a goodish pedal andfront brakes are fine.take grips off and foot to floor with no brake front or rear.any ideas please

[dandadan]

have you definatly tightened up the pipes and bleed nipples? are any of your slave cylinders leaking? with the ignition off can you pump your pedal and make it slightly hard or not?

[LesterPiglet1]

Have you adjusted the rear brake shoes correctly? If they are not, the pedal travel will be taken up trying to push the shoes out further.

[aide47]

definetely no leaks.with engine off the brake can be pumped up but lost if ignition turned on.could the compensator maybe have anything to do with problem?clamped all flexi hoses today except nearside rear and had hard pedal but lost it when trying to bleed it.can pump all day but no fluid or air seems to come out after initial splurge.chap who fitted new handbrake cable maintains brakes adjusted properly and insists its prob master cylinder fault.but it was fine before we started and have not messed with cylinders or calipers except for trying to bleed them.please help

[LesterPiglet1]

Is the pedal lost completely when the engine is running? It's normal for the pedal to drop when the engine is started, this means the servo is doing it's stuff. It shouldn't go to the floor though.

[dandadan]

when you press your brake pedal you are pushing a piston and if you push your pedal to the floor you do run the risk of pushing this piston past its seal. i would double check the rear brakes are adjusted properly. with the handbrake on do the rear brakes hold solid as they should? also check to make sure the brake fluid remains topped up. also when bleeding make sure the brake pedal is pushed down before the nipple is open and the pedal remains down till the nipple is tightened as lifting the pedal whilst the nipple is open can draw air in to the system.

[dandadan]

one other thing, is this model fitted with a load apportioning valve located on the rear axle? if so, you will need the wheels on the floor to beable to get any air/fluid to come through the bleed nipples. it would be easier if 2 guys sat in the back to get some weight in the rear of the car, this will open the valve more allowing fluid to travel to the rear brakes. to bleed the rear brakes on a car with a load apoportioning valve all 4 wheels should be on the ground or 4 post ramp so the vehicle is flat if the wheels are left hanging the valve will shut preventing fluid getting to the rear brakes so try bleeding it with all the wheels firmly on the ground.

let me know if this helps

dan