Hi there,

(Long time no see ). A problem with brakes appeared today. I was fixing the gaiter on the drive shaft and after the whole operation I lost my brakes. The only operations with the brakes were the following:

1. My girlfriend was pushing very hard on the brake while I was trying to undo the hub nut (car was on the wheels).

2. After I fixed what was there to fix (2 hours or so) I had to clean the brake properly, so I pushed the caliper cylinder all the way back (by exercising force on the caliper before dismantling) as I always do, dismantled, cleaned up, mantled back together.

3. Now I have very poor brakes (but it does brake), the pedal goes to the floor and I cannot pump it up really.

What possibly could have gone wrong here? My brakes were always very healthy and kept in good shape, I briefly checked for leaks, found nothing. I remember rallycinq saying something about inverting a seal in the master cylinder some long time ago? Am I looking at a new master cylinder? Or did I somehow managed to get air into the system (how the hell would that be possible)?

Cheers,

Woj

hmm, weird one that. cant see how you'd get air in the system by pushing the pots back. i'd try bleeding the whole lot first as it is the cheapest thing to do. possibly one of the sliders is binding, so each time you brake the whole caliper is flexing and when you release its forcing the pot too far back into the caliper as everything straightens back out?

On top of everything else I am very limited with time and it goes for MOT very soon (hence the fixes I had to do).

The binding slider... Don't think really, cause I checked it, but you gave me the idea that maybe I did not put things back together properly (routine is a very bad thing ). Not much to not do properly, still possible though .

Cheers,

Woj

Try bleeding it, but I think it'll be the master cylinder.

It's really not necessary to use the brakes when doing the hub nut: usually the handbrake and putting it in gear is plenty. Pushing the pistons right back without removing the filler cap can also result in problems (and isn't really necessary).

Guide here.

When you pushed the piston back, did you slacken the nipple and remove the cap on the reservoir? If so didn't you may have damaged a seal in the MC, but hopefully a rebleed will see you sorted

Guys, thanks for all that help. I am so damn embarrassed It was badly assembled, one pad was not fully bedded in its position. Routine is bad, bad, bad, bad.

Regarding the other tips:

I never ever open the reservoir, nor the bleed valve, for me this is asking for trouble, properly sealed system should stay sealed . I always simply do things carefully/slowly, and never had problems (as said my brakes are top notch, just the service guy today had a bad day, I was repairing two cars at the same time

Regarding the hub nut: maybe so (the brake is not necessary). However I totally failed undoing it It is seriously stuck. I changed the gaiter (wheel side) in situ. Plain simple, just one has to watch the higene carefully, that's all. Problem will be if I have to actually remove the shaft one day...

Cheers, thanks, and sorry for wasting your time,

Woj

Glad you got it sorted.

The hub nuts are tight. If you knock up where it's knocked in, a 6 sided 1/2" drive socket, a decent extension (or a breaker bar) and a length of tubing (doesn't need to be thick -- old exhaust tubing will work fine) will do it. Obviously, the longer the extension, the easier it is. Some people just take an air tool to them -- brutal, but it does seem to leave the threads intact on the shaft.

fingers99 said:

Glad you got it sorted.

The hub nuts are tight. If you knock up where it's knocked in, a 6 sided 1/2" drive socket, a decent extension (or a breaker bar) and a length of tubing (doesn't need to be thick -- old exhaust tubing will work fine) will do it. Obviously, the longer the extension, the easier it is. Some people just take an air tool to them -- brutal, but it does seem to leave the threads intact on the shaft.

Click to expand...

i use a big ass 3/4" drive electic impact driver thingy......you dont even need to knock the tabs back out(only did it on a scrapper)

160psi and a 1/2" blue point does it for me! never had a problem with threads, mind you i do them back up with a torque wrench.