ZX Volcane - Very hard brake pedal and weak brakes

[robsons]

Anyone any ideas where to look first. Pads are fairly recent and up until yesterday everything was fine. Got into car and brakes now feel very hard and need a LOT of effort to lock wheels.

[zxTd]

check vacuum connection to break booster to and from the inlet manifold, other thing to consider is an air lock

[Peter.N.]

If its a diesel it wont have a manifold connection as it has a vacuum pump, if its belt driven, check that the belt is not slipping. If its petrol, as zxTd says.

[robsons]

Sorry about that - yes it is a diesel but I don't think the belt's slipping as powersteering and water pump are fine. Just wondered if anyone has had this situation and what caused it. Was thinking of the vacuum pump but also about the rear compensator valve etc etc

[jeremy]

All ZX diesels have a vacuum pump operating the brakes. All are driven off the camshaft rather than the auxillary or cambelt - some by a belt and some directly. Our 1994 ZX 1.9D has a direct drive pump.

It sounds as though you have no servo assistance. Engine off - pump the pedal about 5 times to collapse any vacuum, then with your foot on the pedal with the slack taken up, start the engine - you should feel the pedal sink as the vacuum is created.

If the pedal doesn't sink - then you've got a problem. the servos and pumps are generally reliable. To test the pump properly you will need a vacuum gauge. Having established the pump is working the fault must lie in the servo unit.

Check all pipework carefully - especially if someone has removed any of it recently as its possible to block the hose if the end has deteriorated and gets trapped inside as the hose is fitted.

[robsons]

Thanks Jeremy

I'll have a look tonight

Stuart

[zxTd]

it was the "servo" I was referring to cough I could remember its name that's why I mentioned the vacuum pipe to the inlet manifold which is what feeds the servo