Update coming soon.
Efso and I, we have allready bleed my car with Abs running.
Probably this weekend we try to bleed and efso fd so we can be sure about the result if bleeding with abs help.

 

Just a thought....the actual insides of the ABS is "black magic" to me.
Can you get it to cycle by having the car on jacks, with the engine running, and turn one wheel by hand while keeping the other stationary.
Might that be enough to trick it into thinking you had locked up a wheel?

 

Maybe you can activate like that the abs.But I think that abs activated after 20km/h or more.
So I dont know if you can turn the wheel with that speed with hand.
I am not sure about that.

 

more on this please! i'd like to say i never had this problem until i removed all 4 calipers to paint them. i pushed the pistons back while they were off so all fluid was out of the calipers, and i didnt pinch the hoses so im sure air got into the system that way. i have not tried it while running as it isnt running right ow, but if i pump the pedal 3 times its becomes stiff, but only stays stiff for 5-10 seconds and then i have to pump it up again. this is after bleeding with a vacuum pump (which i know isnt the best). i'll try tommorrow with normal bleeding with another person, if that doesnt work i'll try a power bleeder. btw you could also activate the abs im sure by putting the car up, letting it run, pump the brakes, open a rear bleeder, give gas till the speedo shows enough speed to activate abs, probably like 15-20 mph or something, and then just slam the brakes. this should open the abs system, push out fluid, and hopefully expell bubbles from the abs into the normal lines that can easily be bled like normal ( dont forget to have someone tightne up the bleeder before you let off the pedal) perhaps try again on other rear caliper. who knows i dont...please update Petros

 

Any updates?

Thanks.

Dave

 

Not sure if this helps you guys or not, but I just replaced my tired stock MC with a rebuilt 929 unit from ray @ malloy. I fabricated new lines to the 929 unit. Bench bled the MC on my workbench, and under the hood then completely bled the system of old (8 months) fluid with fresh fluid, my pedal is now rock hard, no double pump. I just did a track event last weekend and the brakes performed flawlessly the entire 2 days.

 

Thread resurrection! has this ever been truly figured out yet? I'm having this problem.

 

Hello, I'm having this problem now. After a long winter's rest in my garage, my pedal now falls to the floor when first applied and is normal upon the second press of the pedal. I have to do a quick tap of the brake pedal when needing to stop. My brakes were just fine last October when I put the car up for storage, now this. I must admit though, its been awhile since my last brake job or flushing.
If you've come up with an answer to this, please let me know, and i'll do the same if I find out anything.