Thread: A new car!
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Unread 08-28-2019, 10:27 AM   #212
GlenL
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Default Pressure brake-bleeding

No progress on the engine problems. Pull it, take it apart and see what's what? No rush to take on that work right now.

I did resolve a mushy brake pedal. My assistant (kids) are grown (mostly) and at least less available for brake bleeding. To get it done, I grabbed a vacuum pump/bleeder and used that for some bleeding and flushing. That moves a fair amount of fluid but I'd notice at some times it'd be foamy. I chalked that up to air leaking in around the bleed screw. Nope. It was sucking in air through the seals.

That turns out to have been a big mistake. An ex-Porsche tech finally told me that the vacuum bleed will suck air in through the caliper piston seals and seems he was right. After first doing it, I'd try some pedal-pumping bleeding when I had help which would make it better and then I'd vacuum bleed it which would be no change, or worse. (Duh!)

At the track, the ex-mechanic told me about problems with vacuum bleeding and a guy offered to use his pressure bleeder on the car. That was a clear improvement.

Back home, I got a Motive Products Power Brake Bleeder model 0100 for European brake reservoirs. It's the cap to the reservoir that makes the difference between kits. I ran a quart through, drove it, and then did another quart. Now the brakes are fairly decent.

So... Don't use the vacuum bleeder. I got it to test vacuum components and help tune vacuum-advance distributors. That's all it's good for.
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1980 928S Euro x2
1987 944 N/A

Last edited by GlenL; 08-28-2019 at 02:26 PM.
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