Brake Pedal Sheethaus

[_x_FiReStOrM_x_]

So, my brake pedal turned to crap over the weekend. The initial part of travel is nothing, and then it bites. I know there's nothing wrong with any parts physically (and no, the system doesn't need a bleed), except the master cylinder I can't be 100% sure of. In the meantime i've adjusted the pedal rod to take up the free travel.

My actual question is: Do R32's have a reaction disc in the booster? I feel this is the most likely cause.

[Sinista32]

bump - good question. Anyone know ?

[_x_FiReStOrM_x_]

Having trouble finding anything conclusive, in terms of parts or part numbers. I didn't really want to have to pull the master cyl & booster out in search of my answer either, if i could avoid doing so.

[Missileman]

get under the car and look up at the booster, is there a fluid leak between the master and booster seal?

[_x_FiReStOrM_x_]

No external leaks visible anywhere, not to say it's not leaking into the booster though. Fluid level hasn't changed apart from the normal drop with brake wear.

The thing that makes me suss, is that it was so sudden. Like one minute full pedal, the next tons of free travel.

I know that its mainly drum brake equipped vehicles that have reaction discs, but i have seen a couple of disc brake vehicles with them drop out (possibly because they use the same booster in a particular model of car as the early drum brake versions).

Nissan dealer, and a couple of local brake/part stores have no listing of any such part. Anybody with FAST, that has a spare moment, care to have a squiz?

Edited February 18, 2013 by _x_FiReStOrM_x_

[Missileman]

If there's no fluid leak then check for vacuum leak, booster test...

http://www.newtonnet.co.uk/coupe/service/webtech/iindex.asp@id=12476

[_x_FiReStOrM_x_]

It's not vacuum related, the booster is definitely doing its job. It's just a big dead spot of free travel, once this is taken up its fine.

[Missileman]

Sorry mate can't help you there, don't even know what a "reaction disc" is.

[_x_FiReStOrM_x_]

All good mate, cheers for the input though.. its always welcome.

In alot of drum brake equipped vehicles there is a small rubber disc attached to the end of the brake booster pushrod. It takes up the initial 'grab' effect that some drums have and gives a more gradual feel to the pedal (my understanding). They used to have a terrible habbit of falling off into the booster, which created a crap pedal. Because the skyline is disc brake equipped i wouldn't have though it would need one, but it is an 80's car and its the only logical thing i can think of that would give this sort of sudden symptom.

Guess i'll have to rip the booster out on the weekend.

[luke gtr]

could be pads sticking on the slides?

have had similar recently.

[_x_FiReStOrM_x_]

It's not intermittent, and not a common thing to have with these sort of calipers, so i wouldn't have thought that. I will double check though - it wouldnt hurt, cheers.