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Model specific boards => Golf mk2 => Topic started by: AL16v on 24 November 2003, 22:13

Title: Bleeding Broken Brakes
Post by: AL16v on 24 November 2003, 22:13
I've seen posts along similar lines before but never really found a definitive answer.

Set up is as follows:
256mm fronts (from a '91 Jetta)
22mm master cylinder (new)
Standard rears (new discs and pads)

After bleeding the brakes several times (with load adjuster clamped in position and rear jacked up high) my pedal is still fairly spongey.  I have clamped the hoses in turn and isolated the problem to the rears.

I have had the calipers off and tried (best as I could) to follow the Haynes procedure for bleeding the calipers before refitting.

Any ideas for getting my pedal feel back ?
Title: Re:Bleeding Broken Brakes
Post by: golfvr6 on 25 November 2003, 00:01
Jack the rear up as high as you can, pump the brake pedal about 40 times, then leave it to settle for half an hour then bleed the backs again. Do you keep get air bubble out of the back calipers when bleeding? or is the fluid clear?
Title: Re:Bleeding Broken Brakes
Post by: AL16v on 25 November 2003, 12:47
I'm not getting any air out at all - which is the problem.

The fluid runs clear (no bubbles) and is new.  ATE Dot4

I can only think that there is air trapped in the rear calipers - can they be bled upside down  ??? or any other way ?

Title: Re:Bleeding Broken Brakes
Post by: golfvr6 on 25 November 2003, 13:47
Try the trick i suggested.
Title: Re:Bleeding Broken Brakes
Post by: Gambit on 25 November 2003, 14:12
this may sound stupid, but you havent put them on back to front (upside down) have you? ie the right caliper rear on the left rear & vice versa?

the nipple is situated at the top when they are fitted yeah?
Title: Re:Bleeding Broken Brakes
Post by: golfvr6 on 25 November 2003, 14:22
I don't think they would fit!
Title: Re:Bleeding Broken Brakes
Post by: AL16v on 25 November 2003, 19:29
Gambit - Calipers are the right way up (bleed nipple at the top).

I'll try the suggestions at the weekend.  The brakes work, it's just the pedal feel that doesn't inspire confidence.

Cheers

Al.
Title: Re:Bleeding Broken Brakes
Post by: golfvr6 on 25 November 2003, 20:05
Are you using a pressure bleeder?
Title: Re:Bleeding Broken Brakes
Post by: mk1 on 25 November 2003, 20:27
Clamp each flexi one at a time, check the brake pedal to see if improves. If it does, then that is were the air is, if no improvement, then the air is in the pipework or the m/cylinder. Had a golf once that I could not get a good pedal on, unbolted the rear calipers and put a old pad between the pads to stop the piston poping out, rolled the caliper around to let any air caught in the back of the piston come out into the caliper body. Then held the caliper so the bleeder was right at the top and hey presto, a good dose of air poped out. Re-fit and all was well, good luck.
Steve.
Title: Re:Bleeding Broken Brakes
Post by: AL16v on 25 November 2003, 22:20
Thanks guys, looks like I'll be busy at the weekend.  ::)
Title: Re:Bleeding Broken Brakes
Post by: DAZZERB on 25 November 2003, 23:41
i had the same problem on my 16 v the problem was there was a gap inbetween the caliper piston and the brake pad when fitted, unscrew the piston, then push the pads in so they are tight, before you bleed them this should tighten them up
Title: Re:Bleeding Broken Brakes
Post by: golfvr6 on 25 November 2003, 23:44
The piston should automatically adjust itself.
Title: Re:Bleeding Broken Brakes
Post by: modulater on 26 November 2003, 00:57
When I changed the calipers on mine I had a nightmare bleeding them, I jacked the back up and left it on stands overnight.with the pressure regulater clamped.

I used a pressure bleeder whilst pumping the pedal to get them to come up.
Title: Re:Bleeding Broken Brakes
Post by: golfvr6 on 26 November 2003, 12:01
I've read its ok to pump the pedal when using a pressure bleeder. Isn't that a bit iffy though?
Title: Re:Bleeding Broken Brakes
Post by: AL16v on 26 November 2003, 12:48
You need to keep a fluid barrier between the air pressure and the master cylinder when pressure bleeding.  It's OK to pump the brakes but you REALLY need to watch the fluid.  It goes through at a rate on knots when under pressure.
Title: Re:Bleeding Broken Brakes
Post by: golfvr6 on 26 November 2003, 14:16
Yep, i've always found it ok just to use the pressure bleeder. Just got to be careful how much pressure is used.
Title: Re:Bleeding Broken Brakes
Post by: modulater on 29 November 2003, 21:35
Yep, i've always found it ok just to use the pressure bleeder. Just got to be careful how much pressure is used.

I found with my brakes that the pressure bleeder wasnt getting it all out and had to pump them as well to get them to come up.
Title: Re:Bleeding Broken Brakes
Post by: AL16v on 24 December 2003, 14:48
Brakes now sorted.  A combination of bleeding them and bedding them in seems to have done the trick.  Passed MOT yesterday, every wheel could be locked up on the rollers.

Pedal still a bit spongey but I can live with it as they stop so much better than the old ones.