Brakes feel like crap.. what happened?

[largeorangefont]

Ok, I swapped front pads and it does the same thing with the low pedal. If I keep my foot on the brake pedal but lift slightly, then push again the pedal raises. If I do this 3-4 times, the brakes engage where they would normally. When I release the pedal completely, the and I push again, the brakes engage very low again.

Is is possible I still have air in the system? Possibly in the lower part of the rear calipers where the secondary bleeder is? I have never had to touch that bleeder since I've owned the car.

[wickedrx7]

Maybe a bad can of fluid?

[largeorangefont]

Maybe a bad can of fluid?

Probably not. I have put over half a gallon of fluid through the system now. All cans were freshly sealed.

I am hoping Charlie might chime in on my question about the rear caliper lower bleeders.

[ls3_rob]

do you have a leak in one of your lines?

[largeorangefont]

do you have a leak in one of your lines?

I do not appear to. I can hold the brake pedal with the car off and it does not sink over time.

The car does have SS brake lines on it.

[Grommit]

I mean, maybe I missed it...but have you checked your booster?

Maybe it has a slight seal leak, and when it warms up the seal swells and closes the leak...just a thought at least.

[largeorangefont]

I mean, maybe I missed it...but have you checked your booster?

Maybe it has a slight seal leak, and when it warms up the seal swells and closes the leak...just a thought at least.

From my research if the booster had a leak the pedal would be harder to push, and it is not. The effort to push the pedal is the same, just where the pedal grabs is different, and inconsistent. I pulled the vacuum line off the booster for a test and the pedal was hard to push, and grabbed in roughly the same spot.

If I hold the pedal with the car off and start the car, the pedal sinks a bit, as it should. If I keep holding and turn the car off, the pedal holds. If I then pump the pedal, the pedal gets firm and rises up with each pump. If I stand on the pedal for 30 seconds with the car off, the pedal does not move at all.

[Mik3ymomo]

So where do I ship this 929 Brake Master?

[largeorangefont]

So where do I ship this 929 Brake Master?

LOL. Let me do a couple more tests. I pinged Charlie to see if he had any more advice. Mine is an OE 929 master and was brand new in the box. I would be disappointed if it was bad.

[largeorangefont]

An update and solution!

http://vid15.photobucket.com/albums/a386/largeorangefont/48E2604D-657E-4F7C-92C2-3D0A8BA955AD_zpssz3ujhfl.mp4

No problems there right?

As it turns out it was poor (or overzealous) machine work on the hubs that was causing this problem. I did not notice the problem until I bolted the rotors to the hubs to measure runout as part of the sanity check I was doing yesterday.

I put the old hubs and used old rotors back on and runout was less than .001".

What suprised me about this revelation was that I could not feel this at all in the brake pedal. I'll have to see if the machine shop can salvage these modified hubs.

[MPbdy]

Holy shit! Yeah that'll do it haha.

If I'm remembering correctly up to 3 thou is "okay" but less is better obviously.

[largeorangefont]

Holy shit! Yeah that'll do it haha.

If I'm remembering correctly up to 3 thou is "okay" but less is better obviously.

That was my understanding as well. My used rotors have some surface heat cracks on them, so I was very happy with less than .001" runout. I'm sure the newer rotors I have are probably perfect, but I can't use them without modifying the hubs.. Oh well.

Edit:
Just went for a drive, the brakes are perfect.