Brake bleed help

[Nickshu]

Just road tested my 911 after a winter on jackstands with many repairs/upgrades including rebuild calipers from PMB, as well as new rubber hoses on the master cylinder.

I was able to bleed the brakes to a good pedal feel using my Motive power bleeder (once I figured out how to pop the pistons past the new caliper seals). Then today when I got it on the road they felt very squishy with pedal travel about 2x what it was originally.

I am about to bleed it again, but wondering if I have air in the master cylinder vs. the calipers/lines.

Should I rebleed using the Motive bleeder (will require me to order another quart of SuperBlue), or should I bleed it via the pedal/assistant method (with the 1/4 quart of SuperBlue I have left) to get the remaining air out?

Any tips?? Thanks!!!

[rusnak]

I would go buy some cheapie Dot4 and complete the bleed with that.

Before you bleed them again, I would check the pad clearance. If the pistons were pressed too far in, then you can have an air gap between the pads and rotors. If so, then take the pads out, tap the pedal right quick, and then retract the pads with a brake pad spreader just until they clear the rotor, then re-install the caliper, pads, pins etc.

When you go bleed the brakes, use the pedal. Pump the pedal and have a helper open and shut the bleed valve really quickly. Don't let the pedal travel all the way to the floor. You might have a ton of air come out the first couple of times.

[plumb4u2]

front calipers are on the right sides correct?

this happened to me, I didn't realize front calipers are not interchangeable (rears are)

[GaryR]

Originally Posted by rusnak

I would go buy some cheapie Dot4 and complete the bleed with that.

Before you bleed them again, I would check the pad clearance. If the pistons were pressed too far in, then you can have an air gap between the pads and rotors. If so, then take the pads out, tap the pedal right quick, and then retract the pads with a brake pad spreader just until they clear the rotor, then re-install the caliper, pads, pins etc.

When you go bleed the brakes, use the pedal. Pump the pedal and have a helper open and shut the bleed valve really quickly. Don't let the pedal travel all the way to the floor. You might have a ton of air come out the first couple of times.

I was taught a trick by my race shop (Dan Jacobs LLC!) to do after installing new or rebuilding old calipers. He called it "exercising" the calipers and it's similar to what Rusnak explained. For this procedure, you should use a set of the most worn out pads you have, or just the backing plates for an old set. Starting at the furthermost (from MC) caliper, with the old pads in and your spreader in place on the rotor, pump the brakes until the pads are at full travel and against the spreader. Push them back in until the pistons bottom out. Repeat this 4-5 times , putting the new pads back in after the last repetition. Go around the car doing the same to all calipers in the "bleeding" order. When done, hook up the Motiv and bleed your brakes normally. I did this after replacing all my calipers as I had a mushy pedal no matter how many times I bled, it solved it.

[Nickshu]

Originally Posted by GaryR

I was taught a trick by my race shop (Dan Jacobs LLC!) to do after installing new or rebuilding old calipers. He called it "exercising" the calipers and it's similar to what Rusnak explained. For this procedure, you should use a set of the most worn out pads you have, or just the backing plates for an old set. Starting at the furthermost (from MC) caliper, with the old pads in and your spreader in place on the rotor, pump the brakes until the pads are at full travel and against the spreader. Push them back in until the pistons bottom out. Repeat this 4-5 times , putting the new pads back in after the last repetition. Go around the car doing the same to all calipers in the "bleeding" order. When done, hook up the Motiv and bleed your brakes normally. I did this after replacing all my calipers as I had a mushy pedal no matter how many times I bled, it solved it.

I ran them out once against old pads. I will try to do it again (4-5 times per caliper) and see what happens. Thanks!