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View Full Version : 80 tdi brake issues. (ABS model)


ross b
29-01-2013, 10:29 PM
Prior to taking my 80 off the road i noticed the drivers side rear caliper was binding, so replaced both rears with new and bled up the caliers. But was unable to fully bleed the system as one of the front bleed nipples had snapped off, also noticed the other front calipers piston wouldnt retract so replaced both fronts calipers. This time the system was fully bled using an automatic bleeding system. A good deal of air came out however the brake pedal was very spongey going almost to the floor with very little bite. The servo is fine, tested this by flicking the ignition on pumping the brake til hard, firing the engine up and the pedal gradually drops away as it should. Im thinking the master cylinder could be at fault so have ordered a new one of those, has anyone had similar problems with their 80's? also are there any top tips to fitting a new master cylinder or is it fairly straight forward? thanks ross
Doctle Odd
29-01-2013, 10:44 PM
Can you access ABS pump with VCDS ? have a look here Ross-Tech: VAG-COM: ABS Brake Pump Bleeding (http://www.ross-tech.com/vag-com/cars/absbleeding.html)
scotty33
03-02-2013, 08:36 PM
Some say you need the engine running, for the ABS modulator to bleed properly? It might help, to simulate a loaded car, i.e to 'fool' the load compensator, there is not much bias to the rears.
mumutley
03-03-2013, 10:30 PM
Hi ross b

"fully bled using an automatic bleeding system" Was this a pressure bleeder? I have known these kill master cylinders due to the pressure they create.

I would also try scotty33 idea and have the engine running whilst bleeding the system
NickPicks
03-03-2013, 10:36 PM
Hi ross b

"fully bled using an automatic bleeding system" Was this a pressure bleeder? I have known these kill master cylinders due to the pressure they create.

I would also try scotty33 idea and have the engine running whilst bleeding the system

I was wondering if it was a pressure bleeder, or a one way valve. I'd recommend a pressure bleeder, but some cars need the pressure reducing to avoid damage to the low pressure side of the master cylinder.