OK - I've got this 1992 968 I bought for parts and the car was just too nice so I've restored it to be a street car - something to beat around in that's the same year and model as my race car.

It sat for 6-8 years. I got it running well and drove around some country roads. Checked the brakes - all four rotors were hot so brakes seemed to be operational. Rotors and pads were just cruddy so I replace with new rotors and pads. Go to bleed the brakes - cannot get hardly any out of the rear calipers. Here's my symptoms:

  • Can't get any fluid out of rear calipers - only a spit or two - pedal will not go down with bleeders open
  • Front calipers - I can pump fluid through but it takes a mule to push that pedal
  • When the front bleeds it feels erratic - pedal won't go, then will drop, next pump smooth, then pedal is rock hard won't move, next pump it'll go down but not smoothly - sorta weird
  • Front calipers will function
  • Rears calipers do not function with pedal depressed
What I've done:

  • Bought a motive power bleeder - this did nothing alone - but it did help when I also push the pedal
  • Started disconnecting the rear lines where there were fittings to see if there was fluid/blockage - no fluid at the rear fitting where the lines disappear under the chassis -
  • Disconnected the lines at the master cylinder and looped hose back into the resevoir - brake pedal works nice and smooth - fluid moved from both lines no problem
I figure there's a blockage somewhere - not sure if I can run compressed air into the system without damaging anything. I was informed not to run more than 20-30 PSI into the lines.

Can I use the power bleeder to push fluid from the rear back towards the resevoir to unseat a blockage?

Any suggestions on this odd problem?