[Mk4 Golf] Spongy Brake Pedal.. too much travel.. - Suspension, Brakes and Chassis - uk-mkivs

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Spongy Brake Pedal.. too much travel..



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#1 Golfin

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Posted 05 January 2010 - 08:21 AM

Ok guys.. now ill explain the situation.. since ive had the golf the brake pedal has felt a little spongy and has had too much pedal travel with minimal response.. i have had a brake fluid service carried out on it and its still the same.. so today i thought id bleed the master cylinder (done it the wrong way round bled the top nipple first then the bottom nipple would this make a major difference) and saw/heard no air be released just brake fluid..


Using the trusty search feature i came accross this post:


From the symptoms you have it's highly likely you have air trapped
in the master cylinder and/or the ABS controller. It's a common problem
with golfs due to the design of the braking system. When I did a fluid
change I suspect I may have let a tiny bit of air into the system which
eventually ended up getting trapped in the master cylinder and ABS pump
and made my pedal near enough travel to the floor before doing
anything. This gave the brakes no feel at all and the whole braking
systems felt soggy and awful. I tried pressure bleeding the system at
least 4 times and still couldn't get them any better. The pedal would
feel hard with the engine off but as soon as you started it it near
enough dropped to the floor. The problem is that the master cylinder
and ABS pump trap any bit of air that passes them during fluid change
and bleeding and this cannot be freed without doing this:


Firstly look/feel along the bottom of the master cylinder below the
fluid reservoir, There is 2 more bleed nipples there (usually with
rubber caps on them). Bleed the lower one first then the upper one. You
should get some air out of here.


If the brakes still don't feel great you will need to get hold of
VAG-COM and run the ABS bleed process. This will prime the ABS pump
(runs the pump for about 10 seconds) then will ask you to open both
front bleed nipples. Do this then press enter on the laptop. It then
asks you to press the pedal down 10 times. Once this is done it asks
you to close the bleed nipples again then it runs the ABS pump again.
You then have to repeat this process about 6 times before it tells you
the ABS bleed process is complete. As I had clear bleed pipes I could
see the air coming out, air that was left in the system after several
pressure bleeds.


I then did a quick pressure bleed of the fronts again for good
measure before seeing if it had helped. I was well happy, no excess
pedal travel (now about 10-15mm free travel), and firm brakes with no
soggy feeling at all. The same if not better than they were when I got
the car.


Try bleeding the master cylinder first but ultimately I reckon you will need to run the VAG-COM process'


 


 


There are two things im not sure about.. after the abs unit has been primed and the nipples are open it says to press thebreak pedal down 10 times will this not cause all my break fluid to leak? will i need to constantly be topping the bottle up? and secondly the brake fluid that spills into the engine bay will it damage any of the components as i know wht it can do to the bodywork.. just thinking of rubber pipes etc..


Also the post says feel along the bottom of the master cylinder for the two nipples.. does it mean the bottom of the reservoir as the bleeding nipples i used were on a metal piece which came off from the master cylinder with the brake fluid reservoir mounted on the top..



Sorry for the long post guys just want to get to the bottom of this really..


Thanks..


Golfin




#2 Golfin

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Posted 05 January 2010 - 11:31 AM

Evening bump anyone???


 



#3 toffs

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Posted 30 April 2010 - 03:19 PM

Golfin - did you find the answer to your problem?  I've got the same http://www.r32oc.com...html#post247542 and wondering what the ABS pump cycle process is ?


 


Cheers,


Toffs :)



#4 Golfin

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Posted 30 April 2010 - 03:32 PM

no bud never got to the bottom of it still the same.. bled the brakes again properly but to no avail.. slightly shaper but still excess travel... i am yet to have the abs bled though so if anyone knows how to do this and would be willing to help me it would be much appreciated...



#5 old_n07

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Posted 30 April 2010 - 03:39 PM

 http://www.ross-tech...bsbleeding.html


HTH


Neil



#6 toffs

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Posted 01 May 2010 - 06:13 PM

 Have a click on the link I gave earlier - Dave Brown (the brake master) has posted some really useful stuff ! :)



#7 Golfin

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Posted 01 May 2010 - 08:11 PM

Neil - thanks mate.. daveb seems to think its pointles..


Toffs.. SO ITS ALL SORTED.. what a head ache it is to do.. now when you say bottom nipple on the master cylinder do you have a picture.. i pressure bled my brakes without having the brake pedal fully depressed was this the error of my ways..?? flippin the seal is what im really really scared of however my brakes are really bad so im willing to try anything..


 


AzRIZ>>> we gotta hit this together!!



#8 toffs

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Posted 02 May 2010 - 12:43 PM

Well, for mine (R32 Mk4) the second nipple is only a couple of inches from the first, its a little lower and a little closer to the bulk head.  Dave recommends having the pedal fully depressed also (but it kinda depends on what method you use).


 


Give Dave a PM if you get stuck :)



#9 bl1tz

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Posted 29 April 2013 - 06:30 PM

Thread revival - Did you ever end up solving this guys?

im having the exact same symptoms - brakes when bled are rock hard but after driving for 5 mins they are squishy and have too much travel.

ive ABS bled the brakes and then done all nipples including the master cylinder and clutch.



#10 bakedbean

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Posted 29 April 2013 - 06:54 PM

 have you checked the sevo pipe from the inlet to servo mine was split and cracked in a few places also the pedal was spongy once changed it was nice and solidYes







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