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Model specific boards => Golf mk2 => Topic started by: paultownsend on 15 February 2009, 13:52

Title: brake pedal 'pump up' question
Post by: paultownsend on 15 February 2009, 13:52
91 '8v gti

im putting in the goodridge hoses next week after 2 years of mot advisories  :lipsrsealed:

when i changed to the front g60 set up, new pads and disks all round (pagid f/r, brembo) i used the 22.2mm m/c. i also used an eezibleed system and the 2 man method.

the stopping power is massive, but still a spongy pedal. but, i find if i pump the pedal gently a few times the feel is very firm. which i like. but then it returns to the spongyness!

is this a m/c, vacume, or possible servo problem?
thanks chaps
Title: Re: brake pedal 'pump up' question
Post by: shakeyjake on 15 February 2009, 13:56
what servo do you have on it?
Title: Re: brake pedal 'pump up' question
Post by: mattkh on 15 February 2009, 13:57
Hi
You dont mention anything about the brake fluid.
Title: Re: brake pedal 'pump up' question
Post by: Dolly on 15 February 2009, 14:19
ive fitted front G60's and rear mk4s with braided hoses all round i clamped the bias valve and pressure bled it twice. the pedal is pretty solid until i unclamp the valve and take it for a drive its really dangerously spongey. should i manually bleed it old fashioned like, or is it more likely the valve has had it on the rear?

im definatly not loosing fluid.
Title: Re: brake pedal 'pump up' question
Post by: paultownsend on 15 February 2009, 14:59
sorry new 5.1 fluid was put in. and the std 8v pb gti servo was retained. and the compensator was clamped fully open  :smiley:
Title: Re: brake pedal 'pump up' question
Post by: DarnPB on 15 February 2009, 18:30
The servo will not cause a spongy pedal. It only assists in braking force. A spongy pedal means you have air in the system and needs to be bled out.
Title: Re: brake pedal 'pump up' question
Post by: paultownsend on 15 February 2009, 18:35
is a proper pressure bleed at a garage the only 'proper' way to go?
Title: Re: brake pedal 'pump up' question
Post by: danny_p on 15 February 2009, 18:40
i've allways managed to bleed them up the traditional way.    vaccume bleediing is optimal tho
Title: Re: brake pedal 'pump up' question
Post by: Dolly on 15 February 2009, 22:13
i pressure bled it, then drove it and then re-pressure bled. im definatly going for the traditional approach next time.
Title: Re: brake pedal 'pump up' question
Post by: DarnPB on 16 February 2009, 08:18
I have never used the pressure bleed system. Always with one in the cock pit, and me at the wheels, shouting, 'down', then 'up', then 'down', then 'up'........
I have used back bleeding before, albeit on light aeroplanes which works for me. You remove some of the fluid from the reservoir, then with an oil can filled with brake fluid, fit the end of the tube to the nipple, crack the nipple open, then pump until all the bubbles come up through the reservoir. Then keep pumping until the reservoir is up to the full limit. :smug:
Title: Re: brake pedal 'pump up' question
Post by: Rodriguez on 16 February 2009, 11:41
+1

I have always maintained I can get a better pedal using the traditional method.   Can never 100% trust the vacuum/pressure way of doing it.  Dealers and garages use them purely to save time.
Title: Re: brake pedal 'pump up' question
Post by: danny_p on 16 February 2009, 18:05
pressure bleeding is bad for meany reasons,  vacume bleeding works much better.   

vaccume belleding is much nicer way to change the brake fluid  tho  as long as there are two people avalibel it is possoble to bleed a car in the conventional manner pritty damb quickly anyway
Title: Re: brake pedal 'pump up' question
Post by: paultownsend on 16 February 2009, 19:47
i think i have found my problem.
today i did my rear bearings. and wound the rear offside caliper back. a little fluid bubbled out of the nipple! i checked the nippple and it was very tight, but i managed to get a few degrees on it. lets hope this was the leek causing the spongyness!
i used new nipples too!