I know you guys change your brake fluid all the time because you are crazy autocrossers, so help me diagnose the problem here.

Basically, my ABS unit was leaking so I removed it and took everything apart and checked all the O-rings etc. I also removed my master cylinder and disassembled it to check if all the seals looks OK.

After I reinstalled the ABS unit and master cylinder, I filled the car up with fluid and tried to bleed the brakes. I was all by myself, so I got really creative. I ended up making a home made check valve and using tubing to connect it to each caliper as I pumped the brakes. Once I got to the point that no air was coming out.. all fluid... I tightened the caliper (It took about 5 tries on each wheel... the system was completely empty of fluid). I went RR FL RL FR. The pedal felt completely firm when I pumped it with the car off. The brakes felt entirely solid.

I even did some brake booster and master cylinder tests from my helm manual, and I experienced no leakage or anything and the pedal did not sink under pressure. Even with the car on the pedal did not sink so I am pretty sure the MC is fine (the seals looked good on the inside...)

(change to present tense) The issue occurs when I start the car. The pedal sinks like normal (brake booster), but the car does not have brakes until I press the pedal pretty far down. I took it out for a spin and the ABS does in fact work just fine, though. If I am just coasting from 50mph and I try to brake, I do not get any brakes until the pedal is at least 50% of the way down. If I quickly pump the pedal a short distance repeatedly while driving, I can get the pedal to engage at the top just fine until I remove pedal pressure entirely. Then the brakes engage really low again.


What do you guys think? I really think all of the air is out of the lines, but I am not sure. I could try bleeding the brakes again... ? Or do you think there is something wrong with some component of the braking system.

Any info will be appreciated.

Thanks,

Dustin

 

It really sounds liek air in the system still.

Also make sure when bleeding not to push the pedal too far to the floor as not to damage the master cyl rings.

YOu could also try bleeding RR, LR, RF, LF which is not the mentioned method but an acceptable method that works well.

ALso try putting a tube on the bleeder screw and put it into a bottle of brake fluid and that will prevent air from being sucked back in if you do it alone.

 

i would say bleed the system again and have someone help you so it goes alot easier

 

Try bleeding it in this order with your ignition turned on:

Left Front
Right Front
Right Rear
Left Rear

Of course, make sure the fluid level never gets below the "min" mark. Sometimes, it takes more than one or two bleedings to get all the air out.

 

I'll have to try this method b/c I'm having the same exact symptoms as Dustin

 

order doesn't make all that much of a difference, but, it will take MORE than one session to get air out of your brake lines. and i mean, multiple, multiple bleed sessions.

take a rubber mallet, and whack the **** out of brake components while bleeding. frees up bubbles in the lines, ie, those little ******* bubbles have some serious suface tension.

bleed on brother.

D

 

You know, it's funny how well whacking just about anything that doesn't work actually WORKS most of the time. lol

 

OK, I went to a pet store and bought some aquarium check valves and clear tubing and used that to connect to the caliper bleed valves.

My brake lines still had TONS of air in them, they are all good now. With the check valve setup, it is really really easy to bleed the brakes now!

Thanks for your help, the brakes are fixed.

Dustin