JasonS4+Festicle

So, last PM I decided to try a bleed with the ABS pump running. According to Bentley, bleeding from the driver's front caliper while running the ABS pump is the recommended way to get air out of the ABS pump (or as Bentley calls it, the ESP pump).

Anyway, it took all of 5 minutes and my braking power is back to 98%. I only bled from the driver's front caliper. Now, there are 4 lines coming out of that pump and if I have any air in those, I'd think I need to bleed from all 4 calipers while the ABS pump runs to get all the air out.

When I say 98% better, I can panic stop and activate ABS at 80mph without a problem - not even a possibility prior to doing this. There is still some amount of "extra" pedal travel - I'm thinking there is still some air in there.

I'm hoping the brakes will be at 100% after bleeding all 4 calipers with the pump on.

For anyone who plans to try this in case they think they have air in their ABS pump - make SURE you watch the fluid reservior as much more fluid comes out than with normal pressure bleeding or normal pedal bleeding since you're using a pump to pump out the fluid.

Also, does anyone know if it's safe for the ABS pump to do all 4 again in one session? I'm assuming the ABS pump is not designed to run for multiple 10 second intervals in a row. I don't want to overwork the pump. Should I do the fronts one day and the rears another to give the pump some time to cool down?

Thanks again to everyone who has helped me sort out this problem - they brakes are almost at 100% and certainly MUCH better. There is hope!<ul><li><a href="https://forums.audiworld.com/s4/msgs/1925209.phtml">https://forums.audiworld.com/s4/msgs/1925209.phtml</a</li></ul>

O.W. Kenobi

during each caliper bleed. That was about a year ago, and I haven't had any problems. AFAIK, you can do them all at the same time.

I'm really glad that you got the problem solved finally. Brake issues are unnerving. Time to get out and enjoy them!

RKA

and we all learned a thing or two. I still don't understand the correlation between your observations, and the ABS pump, especially in light of the 1700 psi measured at each caliper...but at least if I get stuck in the same boat, I won't have to beat my head against a wall to fix the issue.

JasonS4+Festicle

and unsafe.

I haven't even been driving the car that much since this all started because of the safety factor.

The bad news is, I need to re-install the ECS Stage III calipers/rotors since I changed back to stock to trouble shoot.

When I do, I'm just going to bleed everything with the ABS pump on.

It's really amazing what a little air can do to a hydraulic system.

I stll don't understand how my front calipers were showing 1700psi at the caliper but my braking power was reduced - you'd think if I was developing that much force I would not have even noticed a problem.

JasonS4+Festicle

bruises on my head from all the beating it against a wall I did

djillusion

jason, happy to hear you are all squared away!

SAC-CA-GTI

under hard braking/ABS kicking in the rears don't get as much work. I cycle my ABS like 4-5 times and didn't have an effect on it. Glad you got it worked out!

SpfldS4

Do you need to have the brake pedal depressed also?

JasonS4+Festicle

how fast the fluid level would be dropping in the reservior so I had him running the pump with the VAG and watching the level. Now that I've done it and know that with a full reservior to start with one 10 sec run won't empty it, I'd do it alone next time for the front calipers.

If you did it for the rears, it might be hard to get your laptop to reach back that far. It would be hard to run from your computer, back to the caliper, open then close the bleeder valve and be done all in 10 seconds (the pump runs for 10sec when you activate it via VAG)....

We did nothing with the brake pedal at all.

If the pump can take it, it's a really easy way to bleed brakes quickly. One 10 sec run bleeds waaaay more fluid off than 10-20 pumps of the pedal.

dscottjr

Congrats man, glad it was a simple (but not easy) fix.