Mangonesailor

Curious question: do any of y'all bleed your brakes with the engine running to apply vacuum to the brake booster? I've had a couple if boosters fail on other cars right after bleeding the brakes (engine off) so I just do it with all my cars. Are the 944 boosters that fragile?

NM'87 951

Any info on that would be appreciated. Haven't heard about bleeding brakes with the car on, but I guess I could do it easily enough.

Thanks for the power bleeder advice. I'm going to gravity bleed, and vacuum bleed the brakes tonight and see what happens. For my first time ever bleeding brakes, on any vehicle, this is a great learning process.

951mcomm

you are on the right track but i would not open both bleeders at the same time. Do one at a time. Continue to add new fluid to the reservoir after each wheel. you may have to do it a second time if there is a lot of air in the line. If you have 4 jack stands take all the wheels off at the same time. It will make the job much easier.

lart951

I do it with the car off

NM'87 951

Thanks, I started trying it doing both at once, figured I'm ambidextrous... the last time we did it, we did one at a time. I'm starting to think I'm just going to need to be more patient, and spurt more fluid. I swore, the first time, we had steady streams. The second and third times my helper swore he had streams and cut the valves off mid stream (doing them one valve at a time). I did notice though that on some of the valves, the pedal had a noticeable difference in pressure when pressing with the valve open. This went from harder to lighter after a few bleeds, which made me think I'm on the right track here.

I have been searching all day online, finding different threads about people bleeding them. Most of those threads preach patience... so that's what I'll use.


Figured as much, thought a vacuum issue would make the brakes feel even more spongy. My pedal feels pretty good, with minimal fade at the low point of the press (with wheels on), but I get no grab on the brakes. If I do a skid test (press hard and hold the pedal) I get some corners that lock up, some that don't.

Off to pour a beer and do this one more time!! Going to get a power bleeder when i order my SS lines, would be nice to make this a one man job. Thanks for the continued help, and I'll update this all when I'm done.

Dougs951S

This is going to sound like a stupid question so please dont take offense, but I saw you Say it was your first time ever bleeding brakes. Are you sure you are bleeding them right, or that your helper isnt making any mistakes (ie letting up on the pedal with the valves open, ect)? Bleeding brakes really shouldnt take long. I had to replace a brake hard line the other week and with help from a buddy ( my power bleeder is on loan to another friend ) we bled all 4 corners in ~5 minutes once the wheels were off.

NM'87 951

No offense taken at all! No, I wasn't doing it right. After reviewing technique with those in the know, I was doing it wrong. I'll be using correct technique today, and then I'll edit all this to sound like I knew what I was talking about