I've had an ongoing problem with pedal fade with my brakes for I don't know how long. If I'm stopped on a slope and put steady pressure on the pedal it will slowly go to the floor in about a minute or so.

I've recently put speed bleeders all around and have bled the brakes several times. NO air comes out of any of the bleeders. But the pedal fade continues.

Anyway, on to the specific question. I noticed during my last bleed that there was a wheezing sound coming from the front driver's side caliper when I depressed the pedal while bleeding. The wheeze changes as the bleeder is opened and closed. It cannot be heard when the bleeder is fully closed. But...

The pedal was very hard after that bleeding. But I could still push it to the floor, but it took a *lot* of effort to do it as compared to when the car is running. I assumed that whatever had previously caused the wheeze was still happening, but happening so slowly that the noise was inaudible.

-- any comments on the wheeze?

-- any comments on the pedal fade? I have not yet found any signs of a fluid leak anywhere, and I replaced the brake master cylinder about a month ago (thinking that the old one was responsible for the pedal fade.)

 

do you notice any fluid loss over time? if so the master cylinder might be leaking into the brake booster which would be hard to see. or you might just need a new brake booster, not exactly sure what the signs for failure for that are.

if at any time brake fluid has leaked into the brake booster it should be replaced.

 

oh and if noise is coming from the caliper i'm almost 100% it should be rebuilt

 

I did notice fluid loss before (forgot to mention it.) I haven't looked at the level since I did that last bleed, which was last weekend. I'll check it tomorrow.

And luckily I have a spare booster in my closet from my last FC.

 

sounds like a bad master cylinder

 

Please re-read the original post. The MC has been replaced with a reman'ed unit.

 

is the mc new or rebuilt? If its rebuilt, u could have gotten another bad one, i have seen it more then once. Is your pedal spungy at all?

 

Rebuilt. It's actually the 2nd one I've put in this summer. The first one had one of its ports screwed up and I couldn't bench bleed it. This 2nd one seems just fine and I haven't found any indications of a leak.

The pedal is not spongy. Not badly, anyway. It is firm, but with continued pressure it goes to the flow. Slowly if the engine is running, VERY slowly if it isn't.

I didn't get to look at the MC nor the booster at all today. Ran errands all morning, got a haircut I've been long overdue for, started using rubbing compound on my hood only to be called away to help another 7 owner across town who was installing a motor. So lots of rotary karma today, but not a whole lot done for my own girl.
I'll try to check it tomorrow.