Austarion

When I first start my car, the pedal doesn't sink, the pedal is hard and has no assistance. After a kilometre or two and deliberate extra braking the pedal goes back to normal. This happens every time I drive the car.
Initially was only a pump or two on the pedal would bring it back to normal.
But it's way past that and now pisses me off.

I reckon it's stuffed. So what's inside the unit and what needs to be done to fix it - it is just seals or is machining required? I haven't looked inside one of these units, but I have one floating around that I'll look at in about a week and a half from now. :roll:

So any help between now and then on this would be appreciated guys....

have you got any air leaks in the vacume hose to it ???? :? :beer

Dunno. Good point. I'll check that out one of these days...

If you're at idle and you push hard on the brake pedal, does the idle change? If so, the diaphragm in your brake booster is is stuffed, and you need to rebuild the booster. If that doesn't happen, you probably have an air leak outside the booster which partially seals itself when things heat up and expand (note - this could still be the booster diaphragm on its way out).

The standard procedure to check a brake booster is apply pressure to the brake pedal, and then start the motor. The pedal should sink further towards the floor. If it doesnt, the booster is buggered.

Unfortunally it sounds like the Diafram is swollen due to fuel vapor & Age... mine did the exact same thing... had it rebuilt a BHSS for $150ish? & what a differance. money well spent.

:beer

sigmaproject wrote:The standard procedure to check a brake booster is apply pressure to the brake pedal, and then start the motor. The pedal should sink further towards the floor. If it doesnt, the booster is buggered.

Yep, knew about that test and it fails magnificently. The strange thing about it is that it comes good after some driving. The first time I break I get reminded that I've got to stomp on them so they'll work...which has been a bit disconcerting at times...

Oh, and thanks guys. Could it just possibly be the vacuum hose?

Is the check valve in the vac line working ok?

Umm, not that I've had a look but where's that located?

enthuzed wrote:Umm, not that I've had a look but where's that located?

usually on the firewall above the rocker cover and it's a one way valve that's in a line/hose between the plenum/manifold & the booster

Thanks Oldie. Mate, I'm addicted to watching that boxing avatar BTW, over and over... :)

enthuzed wrote:Thanks Oldie. Mate, I'm addicted to watching that boxing avatar BTW, over and over... :)

Mate thats not boxing that's mixed martial arts in ULTIMATE FIGHTING in THE OCTAGON
My son has heaps of discs and has been to Japanto see PRIDE &to Thailand for some MUAY THAI training as well He put it up I can't do it :(

OLD FART wrote:

enthuzed wrote:Thanks Oldie. Mate, I'm addicted to watching that boxing avatar BTW, over and over... :)

Mate thats not boxing that's mixed martial arts in ULTIMATE FIGHTING in THE OCTAGON
My son has heaps of discs and has been to Japanto see PRIDE &to Thailand for some MUAY THAI training as well He put it up I can't do it :(

Any tips from him on how he put that up. And yeah it's not boxing, that's for sure! Damn good though!

Sorry to get back to the topic, but I once had a Gemini motor running on three & a half cylinders, turned out to be a stuffed brake booster robbing vacuum from No.4 cylinder. Enthuzed, is your motor idling smoothly on all 4 pots ? :?