Need help on brake issue - 964 Carrera 2

[AlexJ]

Hi all,
I recently disassemble the four brake calipers to paint, as well as the ABS pump on the front trunk in order to clean the area.

Today I have been assembling all the parts.
After bleeding the calipers through the typical method (pumping the pedal to make the air out - no pressure machine was used) something strange happens:
After I bleed the four calipers the pedal feels fine with the normal hardness.
After I start the car, the pedal goes down and I have to pump it two times to have it hard again.
Does anyone knows what did I do wrong ? I have been using this method to bleed many G series cars and it always works...
Does it has to do with the fact of disassembling the ABS pump?
Thanks in advance for any help.

[RedCoupe]

I think it's related to the ABS which the G series cars don't have. I have had good luck using the Motive bleeder with my 964. Have to block the vent hose, though.

[AlexJ]

Thanks for your reply. Do you know if it is possible to bleed the ABS pump alone?

[RedCoupe]

Originally Posted by AlexJ

Thanks for your reply. Do you know if it is possible to bleed the ABS pump alone?

Probably by loosening an output line
Could be messy though.

[Bill Verburg]

I always use a pressure bleeder on ABS cars

you have air in the ABS pump

the air can't be easily removed w/o cycling the pump, You will need a hammer or Piwis to do so.

w/o a Hammer or Piwis the only other option is to try to lock, thus cycle) the brakes in use, hopefully on a closed road.

[KaiB]

It could very well be possible that the seals in the master cylinder were damaged during the bleed process. Old M/Cs do not like being extended in this way - the pedal pump method can over extend them.

[AlexJ]

Thanks to all of you.
I will try to get a pressure bleeder and repeat the hole process.

[YaHoo!]

I opened my abs pump on a 964 c2 and used the power bleeder successfully to eliminate air from the system although it took several bleeds before the lines were clear of air.

On a C4 there is a slightly different abs system which requires a special bleed proceedure.