99 Audi A4 Quattro 1.8t

I replaced the caliper on the rear passenger side. Put it on, lines are all tight going to it.

I cannot for the life of me get a single drop of fluid out of this caliper.

I have tried bleeding them the ol' fashioned way with a helper.

And now I have tried bleeding them with a vacuum pump.

This is what I am doing:

1. Key off
2. Open Reseviour
3. Place bleeder pump on bleeder screw
4. Built PSI to 15
5. Cracked open bleeder screw a bit
6. watched pressure drop to 5
7. Closed screw
8. Built pressure to 15
9. repeat, repeat, repeat

No fluid. Is there some sort of magical way to do these damned things? Never had so much trouble in my life. Also, this has ABS.

 

Did you lose a bunch of fluid while attaching the new caliper? Did the reservoir run dry?

Have you tried bleeding any other wheels? I have had better luck bleeding in the opposite of the traditional order. Try starting from the driver's front. If everything goes well until you get to the new unit, you may have a bad caliper.

 

Full fluid

All good calipers. For sure.

 

I did not loose ANY fluid either.

 

no fluid at all? even when you took the old caliper out? that would be a large problem. was that brake working at all? like was the rotor rusty?

 

How are you expecting to build pressure with an open reservoir?

 

the resevoir doesnt really hold pressure. like any hydraulic system works, the brake resevoir just holds additional fluid that is introduced into the sytem when it is needed. its how older cars got away with a resevoir cover that just snaps on. the fluid in the resevoir gets used when the piston is pushed out further as the pad wears thinner. then when you retract the piston when you change pads, the extra fluid goes back into the resevoir.

i would be concerned if no fluid came out of the old caliper. it probably means the line is kinked somewhere or blocked somehow

 

heres a good pic. when the piston(s) extend, it blocks off the resevoir(s). when they retract, if fluid is needed, the resevoir will allow additional fluid into the system

 

Cool, honestly I've never seen that. Guess I never gave it enough thought - thanks man.

 

no problem. i usually dont get my rocks off correcting people, but i thought it was relevant to this thread