1999 VW polo excessive brake pedal travel

appytiser · 13 Sep 2005

Just renewed master cylinder, front dics's and pads and rear brake cylinders but still have excessive pedal travel. Ive bled the system several times, even bought a pressure bleed system to work of my compressor. System appears to be air free. Any suggestions?

Jimmyjaffa · 14 Sep 2005

Hi i've had this on numerus cars when ive changed disk and pads, the pedal seems to go to the floor, but after ive drove the car for a while the pedal started to come up and after about a day or so ended up with a normal pedal, try using the car a while and bed the brakes in abit but take it easy.

johnwr · 15 Sep 2005

Hello, If you clamp off all the flexible hoses and then try the brake pedal if there is no travel then you can let each clamp off in turn and this will quickly show you where the problem is. If you still have a long pedal travel check the master cylinder. A word of warning do not use mole grips to clamp off the hoses, it will damage the hoses

davedasave · 19 Sep 2005

have you got abs? if you have you need diagnostic equipment to run the pump because the abs unit will be full of air and the only way to remove it is to run the pump while bleeding the brakes, quite hard to do without a computer! hope it helps

steve_s46 · 20 Sep 2005

Has it got drums on the back? If so check the "automatic" adjusters - these sometimes stick or get clogged with brake dust so the shoes end up sitting a long way from the drum = long pedal travel to take up the slack. The abs shouldnt need bleeding unless you have opened the bleed screw on the abs unit itself or disconnected any of the pipes. If you just disconnected the m/c it should be ok. Does the pedal firm up or just go all the way to the floor? Also if u put even pressure on the pedal does it slowly sink to the floor?

davedasave · 20 Sep 2005

when you fit a new master cylinder, as soon as you put your foot on the brake pedal it's going to push all the air straight into the abs unit, thats if its got it, and no matter how many times you bleed it you'll never remove that last bit of air without running the pump, it might be worth using the abs in anger to see if that shifts it

steve_s46 · 21 Sep 2005

I replaced the brake lines on a polo (1995 model though) and just bled the system at the wheels and pedal is nice and firm. The valves in the abs unit only open when the abs cuts in, so unless the bleed screw on the unit itself has been opened there shouldnt be air in there.

Also feel the pedal travel with the handbrake on - if its less then the problem is likely the rear drum adjusters. Flexible hoses can also buldge when old and give bad pedal feel but is probably unlikely to be the cause here.

appytiser · 23 Sep 2005

Hey, thanks for the response. The car does not have ABS but it does have rear brake drums, when the engine is not running the pedal feels ok, but when it is and the servo has kicked in, thats when the pedal travel problem occurs.

keyplayer · 24 Sep 2005

If you're sure the system is air free and the servo vacuum hose is sound then I agree with steve-s46 - the rear auto adjusters are probably stuck, particularly as you've had the drums off. If you pump the pedal quickly does it come up at all? If so there's air in the system somewhere, otherwise get the drums off again and have a look.

steve_s46 · 26 Sep 2005

The pedal travel will always be longer with the servo assistance (less pedal effort required to push pedal a given distance) but isnt likely to be a servo fault imho - just makes the problem more noticeable. While you have the drums off also check the shoes arent binding on the backplate - but self adjusters still the prime suspects.

1999 VW polo excessive brake pedal travel

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