Darien

I finally got around to using the power bleeder. I used Dot 3 silicone fluid and flushed a total of 4 liters though all 8 bleed ports. It seemed to go pretty smooth until I finished and took her for a ride. Now the damn pedal travels to the floor Anyone else have the same results using the power bleeder, what could cause this?? I didn't allow any air in the system, but that's what it reminds me of

ErnestSw

Did you let the power bleeder run dry? If you let the level get too low you'll ADD air to the system.

Darien

I kept a close eye on the level and the fluid coming out of the bleed ports, they were steady and no air bubbles

Paul D

Darien - I hope you meant you used DOT 3 synthetic brake fluid and not silicone. Right?

Jim M.

I think your problem may be using "SILICONE" fluid. Porsche does NOT recommend using silicone fluid because it causes corrosion and other problems.

Jim Mayzurk
93 GTS 5-spd

Schocki

You must have induced air into the system. Did you also bleed the master cylinder (it has it's own bleeder).

Garth S

Did you happen to either replace the pads? - or push them back for a check? If so, the brake pedal must be 'pumped' to bring the pads back into contact with the discs: if not done, there is a sickening feeling as the pedal grabs the floor on first application.
If this were the case, a couple of pumps, and the pedal should be firm again.

If not, then as everyone says - there is air in the system: liquid is not compressible.
BTW, 4 liters is a wack of fluid. I find that a liter will bring everything clean, whether using a pressure bleeder or the two man - pump the pedal routine. There should be little turbulence within a hydraulic system, so what is termed 'plug flow' prevails .... so basically, all that is required is a non-mixing replacement of the volume of the system.

FlyingDog

Either Dave or Jeannie told me the system holds about 3/4 liter. 4 liters for flushing is massive overkill.

Darien

Yes Synthetic was used, my mind was somewhere else!! As for the Master Cylinder, I didn't bleed it. The pads were not touched. Could the master cylinder trap air during the bleed?

FlyingDog

Yes, it could. I bleed it first and last.

Darien

Well, I'll do it again plus the master cylinder tomorrow

the flyin' scotsman

1 litre of fluid, get the pbleeder up to pressure, wheels off, crack all 8 bleeders, one at a time, until the new fluid flows, tighten the bleed screws, do the m/cylinder, releive pressure, install wheels and drive.

4 litres is too much fluid to go through, use an alternate coloured fluid so you can see when the new stuff is flowing.
If I remember correctly did you not have the pistons out of the calipers? Are the back in ok with new seals?

Darien

I wasn't concerned with using over kill on the flush/bleed. When I had the issue with the calpers and performed the "follow-on bleed, I had some milky stuff in the old fluid. I wanted to make sure all the contaminated stuff was out.

Bill Ball

FOUR liters?! Wow! When I do a flush with color change, I go through less than a liter.

Anyway, I wish I could help you, but I have not had any trouble with the power bleeder.

FlyingDog

When you're bleeding the calipers rap them lightly with a hammer or the handle of a screwdriver. That can help loosen stubborn air bubbles in the calipers.