Scary Brake Problem

[JamesB]

On very few occasions when i press the brake pedal it is rock hard and only moves an inch or so - worst thing is the brake hardly do anything (no boost in them). Ive been told by a good mechanic it maybe the vacuum check valve getting suck or a leak in a vacuum container. Has anyone come across this before - if so, where is this magical check valve. I aint to keen on driving her as Ive come very close to rear ending someone because of it (took a little paint off theirs but my baby came thru without a scratch)!! Thanks lads

 

[Fast Guy]

Are you left foot braking while still on the gas. If you try braking on boost you don't have the vaccuum to work the brakes properly.
I think there should be a one way valve in there air line to the servo maybe, but not sure to be honest.
Alternately it could be your servo on the way out, or glazed pads (I think)

 

[turblio]

Same thing happened to me this morning and often does it is vacuum related I think bit unnerving eh? just fitted new discs and pads so its not that used to do it with the old setup so... best check our valves!
Frank

 

[charlie]

i'd think the fault is witht either the one way valve in the vacuum feed to the brake servo, or a hole in that hose.... best check

 

[charlie]

just to add to that... does the servo hold vacuum when u turn the car off? ie. you can pump the pedal until it gets hard. or is it hard straight away?

 

[kyepan]

same here, if i am on the throttle even a bit, the pedal is rock hard.. where is this valve i need to check?

 

[JamesB]

I dont have my r at the moment to test after turnin off (in for a bit o body luvin). If anyone knows where a vacuum line diagram might be - i really wanna have a good look at this valve. I stress though, the problem is very inconcistent so i dont think its a leak anywhere

 

[charlie]

the pipe that runs to the brake servo, from memory its got little stickers with arrows on, on it, the valve is actually inside this pipe. it goes down behind the inlet plenum i think.

 

[gtir drew]

im having the same problem, it seems to only be first thing in the morning. I also have the problem that my abs does not work! the wheels will just lock up. If any one has any more info bout the abs please let me know.

 

[Anonymous]

Try cleaning ur wheel sensors mate. A nice jet wash with the spray aimed inside the wheels usually cleans up the sensors. If not then you might need new sensors / wires etc.

 

[JamesB]

Unfortunately mine doesnt have abs so ill have a look at that valve when i get her back