kgoertz

I accidentally let my brake reservoir run dry while bleeding this summer and I'm pretty sure I have air in the ABS unit since I occasionally get a "Brake fluid low" message when I'm a little overly aggressive in the rain

Using a Durametric system might be the solution and I think it might be worth a try before bringing to my indy.

If anyone locally happens to have a cable for sale (or that I could rent) I'd appreciate it. I haven't really had a need for one yet so I'm not convinced I'd use it often.

Thanks!
Kevin

Imo000

Kevin,

I don't have one but from what I know, the problem with most of these cables is that, unless it's the professional version, a VIN of the car need to be registered to use the cable and these cables have limited number of VINs that it can take. I'm not sure if there is a generic version of the cable available on eBay that will have the capabilities to bleed the ABS or not. They do for VWs.

Cosmo Kramer

Hi Kevin

If you want to stop by, I can check it for you for a case of beer. I have the professional version with unlimited vins. I also have a Motive bleeder. I live 10 min east of KW.

Ted

Turbodan

I don't think duramatic will help you get air out of your system. Just bleed the system with a motive...come to think of it if you have air you may want to do it the old manual way, pumping on the pedal. Come to think of it, air in the line should not cause low brake fluid warning, that is from the sensor in the master cylinder in the frunk, may be a loose wire or faulty sensor. Curious what would make you think air would cause that message? is the fluid full btw?

kgoertz

Lots of good questions. There are lots of articles describing the need to cycle the ABS system during a brake fluid flush particularly if you have air in the system. And I know for sure that I introduced air in the system
There is apparently a 5th brake fluid line for the ABS system that can't be flushed without a computer.

Obviously I have checked my fluid multiple times and the error message isn't because my fluid is low. The first time I experienced this was on the track a few years ago. I immediately pulled over and checked the brake fluid and it was fine.

My assumption that the ABS system is related to the message is due to the fact I can almost trigger the "low fluid" light on-demand by getting the wheels to spin in the rain. The warning only appears when I'm driving overly aggressively in the rain which means it isn't due to G-forces, overall low fluid, or heavy brake use. I am assuming that PSM uses the ABS system to control wheel spin and that there is another brake fluid level sensor somewhere but I haven't found any confirmation on that.

On top of this, I have never been impressed with the firmness of my brake pedal on my 996 and I have tried multiple times to flush the system assuming it was due to air bubbles. I recently purchased an 09 335i as my winter car and it's brakes feel much more firm (although much less linear). I'm hoping the ABS flush will solve both problems.

I have read that it may be more effective to bleed the brakes, run the car and trigger the ABS system heavily, and then bleed them again manually (since that approach moves the fluid out faster than using the Motive bleeder). I think I will try that first.

kgoertz

Awesome! Thanks Ted. I may take you up on that. I'm going to try flushing manually today after engaging the ABS to see if that helps, but if not I'll send you a PM.

kgoertz

Just an update for the curious. I took the car for a spin and gave the ABS system a workout. I then did a full flush using my son to apply pedal pressure. All 4 wheels and both sides of the caliper. There were only a few small bubbles from one of the brakes (front left) but less than I was expecting/hoping. It might have actually been quicker than when using the Motive....

I took it for a spin and the brake pedal is slightly but noticeably firmer. I couldn't get the "low fluid warning" to trigger so maybe that was enough to fix the problem. I'll post after a bit more testing.

petee_c

I thought ABS pump used a different reservoir than the master cylinder...

of course, I could be wrong.