[yelcab1]

Originally Posted by darrin

not sure if you followed the recommendations contained in my post on your prior thread regarding this matter -- namely:

this might help -- written for a 993, but seems to also apply to a 964
https://www.pelicanparts.com/techarticles/Porsche-993/36-STEERING-Power_Steering_Fluid_Flush_and_Bleed/36-STEERING-Power_Steering_Fluid_Flush_and_Bleed.htm

Specifically "To bleed the system: Refill the reservoir and quickly turn the motor on and off; this will cause the level in the reservoir to drop rapidly so do not let the engine run long as this can introduce air into the system. If possible have a friend watch but do NOT let the reservoir run dry. Once you can start the engine and the level does not drop let the motor idle and turn the steering wheel quickly and at an even pace from lock to lock several times to bleed the air out of the system. Do not force the wheel when turning. Continue this procedure until the level remains constant and there are no more air bubbles in the system. "

I tried this and it did not work and here is why. The 32 years old pump is shot, air is leaking in and is being pumped through the system making frothing foam. That is never going away by bleeding. I applied vacuum to the system and found it is not holding vacuum which confirms the leak.

So the plan is to replace or rebuild the PS pump and then replace the reservoir. Then, fill and bleed it.