Brake pedal refuses to stiffen! Mk2 golf

[Alex_G60_Fanatic 0]

Hi there...

 

A little help for my pal with his 16v mk 2 golf. The brake pedal refuses to stiffen up and is soft, keeping him from getting an MOT. The car has no ABS.

 

The brakes have been bled 3-4 times now and there is no air in the system, he even took it to a garage to get pressure bled but no joy. The brakes pump up ok and if you do so with the engine off the get stiff and when you turn the key get soft again so the servo is kicking in.

 

The MOT centre suggested that we check each calliper for leaks but the brake fluid doesn't drop over time and there is no visible signs of brake fluid leaking ANYWHERE...

 

Could the seals of the servo be going? The master cylinder is almost new but maybe the slave cylinder seals are letting a little fluid past them maybe?

 

Your input would be most appreciated! :bonk:

[Supercharged 2]

Could be a collapsed hose but when you say the MC is almost new was it a pattern part or remaunufactured? If so I would suspect it's faulty...

 

Could be a leaky servo also I suppose...

[tony_ack 0]

Definitely sounds like seals in the master cylinder

[Alex_G60_Fanatic 0]

Don't know where he got the Mc from... Maybe from MC Dangerous Dan and the no solids crew YO! :afro:

 

I reckon the master cylinder is ok though... I saw it go in and it looked ok. Will mention this to him.

 

Could it be a loose caliper? He seems to think he can hear a knocking sound when he uses the brakes... he fitted a new front caliper to the drivers side wheel. if he ddidn't tighten this up properly could this be the cause?

 

Also, how does one check the servo's seals without removing it?

[jamiehamy 0]

It must be a Mk2 16v thing. I had exact same issue after fitting new pipes to mine. Same thing about fine with engine off. I managed to get it almost perfect, but was always a bit spongy. Worth bleeding the calipers with them off the axle and making sure the bleed nipple is pointing upwards, and it's common for pockets of air to get trapped and not able to get free.

 

Was the brake compensator fully open when bleeding? If not, there might be air kicking about there.

 

If you get a few hose clamps, you can clamp them off and try identify which end, then which side is the offending one? Assuming of course it's not the MC as mentioned. This is the cheap option I suppose :) If clamping the rear twp makes it fine, you know where the issue lies and vv for front.

 

Good luck.

Edited April 12, 2011 by jamiehamy

[Dox 23]

Strip and clean the brakes, make sure the caliper slides aren't seized or the pads seized in the carriers.

[Alex_G60_Fanatic 0]

If you get a few hose clamps, you can clamp them off and try identify which end, then which side is the offending one? Assuming of course it's not the MC as mentioned. This is the cheap option I suppose :) If clamping the rear twp makes it fine, you know where the issue lies and vv for front.

 

Good luck.

 

I think that's what we're doing... it just pains me to see him go through so much DOT 4 with no results. bloody Golfs hey!

[Alex_G60_Fanatic 0]

OK... This is really getting on my tits! This is what we did yesterday:

Right, I'm stumped, Alex is stumped. Changed the mastercylinder out for a known good one. Bled the system and the brakes work, sort of. Theres a lot of pedal travel and after a bit of abuse the pedal will go to the floor when pushed hard. It should stay above the floor about an inch shouldn't not sink all the way to the floor?

 

Changed the front flexi's + hardlines back to the servo with like for like, rear is as it was. Get a strange wheezing sound when pumping the brakes at standstill. Was working fine when parked up in July. Don't think it's the servo as that's the only thing that hasn't been changed and that would make the brakes really hard to push down.

 

Setup is as follows.

 

280mm calipers/ discs

22mm master cylinder

9in servo

 

Only other thing I think I might try is taking off the rear calipers and pushing the pistons back in. Failing that I will have to admit defeat and take it to a garage, who will probably charge me a small fotune, that I don't have

 

Any help gratefully recieved.

 

ALi

 

ALSO

 

1. The servo Kicks in when you turn the engine on (you can feel it after pumping the brakes)
   
2. The noise he mentions above is like the sound of air being blown though a straw. Never heard of this before and am lost as to the cause other than MC but as mentioned above, that has now been changed AGAIN! it's defiantly not the cause.
   
3. Every calliper has been clamped and checked and bled. The brake compensator was open during the bleeding.
   

:scratch:

HELP

[davidwort 0]

had a similar issue on the mk4 last week after doing the rear axle bushes, the only way we got a good pedal (after pressure bleeding and conventional pedal bleeding) was to pump the pedal several times really hard and then crack open the bleed points (one at a time as normal), for some reason this seems to shift air better than any other method and finally I got a good pedal back with the engine on (it seemed OK before with engine off too).

[Alex_G60_Fanatic 0]

had a similar issue on the mk4 last week after doing the rear axle bushes, the only way we got a good pedal (after pressure bleeding and conventional pedal bleeding) was to pump the pedal several times really hard and then crack open the bleed points (one at a time as normal), for some reason this seems to shift air better than any other method and finally I got a good pedal back with the engine on (it seemed OK before with engine off too).

 

Maybe give bleeding one more go.... This would be the 6th time the systems been bled though... It's becoming irritating. The fluid coming out it very clean though, only a week old at the most!

[Harrier 1]

I had same fault some years ago on my 8v mk2,after replacing m cyl found fault to be rear compensator