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Trigger ABS solenoids ?

PostPosted: Wed Jul 24, 2019 3:59 pm
by Foscora
Before I go on and ditch the ABS on my 44 (I'd like to keep it tho), any of you guys found a decent way to trigger the solenoids on the ABS on classic Audi ?

My whole brake system feels pretty decent (no rust or excessive wear) yet I encountered a spongy feeling on my brake pedal recently, like it brakes but if I keep my foot on the pedal at a red light or something, it slowly goes to the floor.

I obviously had thoughts on a dead MC (despite this one being 6 yo and a ATE one) and I went and replaced it -> Nothing changed
I replaced the front hoses which had a few minor cracks -> Nothing changed
I replaced the rear hoses which seemed very neat (on the caliper side) -> Nothing changed
The hoses in between the rear regulator and the hard lines seems in very good shape so I haven't replaced them yet (I plan to do it but honestly, I'm almost sure those won't be my problem)

I purged:
- straight out of the MC
- straight after each line of the ABS
- after the rear brake regulator for each line aswell
- at each calipers

No bubbles even after purging like a small glass of water of brake fluid at each caliper and I still have the same issue. I even tried with engine running and doing the two man job thingy, pressing hard on the pedal ... the pedal still goes to the floor upon a certain time.

EDIT : Oh and obviously, got no leaks anywhere as far as I can tell

The only way I found to temporarily solve my problem was to slam the brakes on gravel and trigger the ABS, then the pedal would feel really hard/how it should be ... for a few minutes then it would go back to the floor ... so I'm still feeling I have an air bubble somewhere and I'm guessing it's located around the ABS, hence why I'm suspecting a lazy/stuck ABS solenoid.

So in case there's an easy way to "play with" the ABS solenoids ... I'd love to hear it.

Thanks in advance

Re: Trigger ABS solenoids ?

PostPosted: Tue Aug 06, 2019 2:15 pm
by audifreakjim
Are you using a pressure bleeder on the brake res or a vacuum bleeder at the caliper? I have always preffered the pressure bleeder.

Re: Trigger ABS solenoids ?

PostPosted: Sun Aug 18, 2019 2:16 am
by Foscora
I did use a pressure bleeder and I tend to prefer those aswell.

Finally got rid of my problem after a few purges and "slam the ABS" in-between. Went to inspection afterwards, car brakes straight so I guess I have no ABS valve stuck atleast.