Just made decision for brake upgrade.

[roger1]

Got my new B body booster on and just test drove it.
I didn't fix the issue so it wasn't the old booster being the problem. I figured the chances were that high though.

The bigger booster made my problem even more pronounced. Upon starting in park I noticed that the pedal was easy to just push down all the way to just off the floor. A definite stop in the pedal is felt so it's just plain as far as it will go.
It will not pump up at all if I pump it rapidly. Goes to the floor with every push.

During the test drive, the pedal would remain high during a normal type stop. Just like before. But even for a moderately aggressive stop, the pedal would then feel mushy and move to far and it did this easier than before. After depressing the pedal to what feels to far, It also lagged coming back up after releasing my foot. It didn't do that before. Could be because the foam insert that the pedal rod goes through inside the boot was completely disintegrated from age.

Seems like I've got to either have air in the system or a bad master and just have to find out which one it is. Dang, I was sure I bled the bench bled the master perfectly and did a diligent job of power bleeding when doing the wheels. I've been doing my own brake jobs for 45 years and never had an issue like this before.

Not sure what to do next but I'm thinking I should pull the master and put it back in my bench vise and test using Dave's method. I don't have the plugs but can make them. I've got 2 steel tube nuts that are the right size and I can weld the holes up with my mig welder.

Since I am pretty confident in my bleed job, I'm inclined to think the master is bad even though it is a new Centric. If I take the master off, I can not only check it to see if it's bad (with the plugs) but I can also see if maybe I somehow didn't get it bled all the way.
That seems to make more sense then just re-bleeding at the wheels first. Not sure though.

I'm not keen on clamping my brake hoses to see what happens. I just keep thinking that wouldn't be good for the hoses. And not sure it will really give me the answer between air or bad master.

Comments will be appreciated Dave.

 

[fleming442]

There's air in it.

 

[roger1]

Air where?
It seems if it were air in the lines, calipers or rear cylinders, the pedal would pump up. It does not.
Maybe air trapped in the master because I didn't get it all during the bench bleeding? Maybe.
But I stroked and stroked way past the last air bubbles. Let it set a while and stroked away a bunch more.

 

[fleming442]

Air where?
It seems if it were air in the lines, calipers or rear cylinders, the pedal would pump up. It does not.
Maybe air trapped in the master because I didn't get it all during the bench bleeding? Maybe.
But I stroked and stroked way past the last air bubbles. Let it set a while and stroked away a bunch more.

Man, look, it's not rocket science, they're a simple hydraulic system. Personally, I've never bench bled a master. There are simple things like: are the bleeders at the top? We've all (well, most anway) had them backwards once.
I usually fill the reservoir, then put a bottle on, and crack a rear bleeder, then let it gravity bleed. Shut it, move to the next, then, on to the fronts. Once fluid is flowing, go onto conventional pressure bleeding. I've even gotten good enough to do it by myself: have the bleeder open with the tube on it, hang the bottle (half full) higher than the brake, and slowly pump the pedal. Shut the bleeder and you're done.
The worst experience I ever had was Seville calipers on the back of my buddy's 71 Z28. We bled them for 3 days! Now, I learned that you need to cycle the e-brake to set the piston....
You'll get it, but stop brain F-ing it don't assume it will fix itself.

 

[roger1]

So, I made myself some solid steel plugs from tube nuts that I had on hand.
I put them on the master while it was still on the car. Started it up and the brake pedal is hard as a rock and doesn't fade.
So it appears my master is good. All 3 of my brake hoses are 5 years old but only have a few thousand miles on them and the car is always garaged. I don't remember what brand of hoses they were but it would seem like a very slim chance that they would be ballooning. So, it appears I must have air somewhere. What I don't understand is why. I've bled and re bled both with this master and the previously one I thought was bad but probably wasn't. It seems like something is fighting with me. I don't know what that could be.
I've bled many, many brake systems over the 45 years I've been working on cars. I've never had a problem like this before. Maybe a couple of times I've had to re-bleed a second time but that's it.

 

[pontiacgp]

I would tap the caliper with a rubber mallet to release any air that may be trapped

 

[roger1]

I would tap the caliper with a rubber mallet to release any air that may be trapped

I know that can happen sometimes so I did do that. I also went a step further. I took the calipers off and supported them as not to stretch the hose. Then I put a C-clamp onto the piston so it couldn't pop out of the bore. This allowed me to rock the caliper back and forth just a little during the bleed to make sure any air wouldn't be trapped. I made sure the bleeder was at the top. Tapped on it a little as well.
Like I said, I think I did a very diligent job and bled much more fluid out than should be necessary. Not sure why this is being such a pig to bleed or if something could be fighting me.
The original 36 yr old proportioning valve has come to mind but since I'm getting braking to both the front and rear and fluid is coming out at all four corners when I bleed, I just don't see how it could be an issue.

 

[Streetbu]

Two man bleed. Get your wife on the driver's seat. Tell her when you say "down" to push the pedal as far as it will go at a medium pressure and once it stops, she should repeat the word "down. Then you crack the bleeder open. Close it just before the fluid stops coming out. Tell her "up" which means release the pedal. When the pedal has fully returned to the up position have her say the word "up". Repeat the process beginning first at the right rear, then left rear, right front, then finally left front. Make sure to check the fluid level in the master between each wheel bleed. That's how I was taught and have always done it and never had a problem...

 

[roger1]

Wife and I have been through that multiple times in the 22 yrs we've been together.
We did it that way on this car not long ago. With the previous master cylinder that I thought was bad. After that is when I bought the Motive power bleeding setup and Power Probe adapter for masters with plastic reservoirs and used that after installing the new 1" master.

I think the next thing to do will be another conventional bleed with my wife helping. Maybe with the driving I've done, some air has gone to the top of the calipers or into the cylinders at the back. She is out of town and doesn't get back until tomorrow night though. She also doesn't like doing this because her leg gets tired. Oh well, good exercise, right?

 

[roger1]

Hooked the lines back up to the master. Tilted lines and filled to the brim with an eye dropper of brake fluid. Removed the master and tilted it to install the lines. One by one removing the plugs quickly. Tightened the master back down and removed the cover.

Gravity bled all 4 corners in order. About 4 oz each. Couldn't tell if I got any air. When I did the rear it bubbled the entire time. I assume air comes around the threads of the bleeder and enters the tube. Front didn't do that. The bleeder threads must be tighter I guess.
No change at all. Spongy pedal that goes to the floor.

It will be Wednesday before my wife can help me do the 2 person method. I could set up my power bleeding system but it didn't do the job the first time so I will wait for wife to get home and help.