TAC Tech > Tires, Brakes & Suspension

Brake pedal sticking to the floor with delayed release.

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tinpusher:
After reading this post again, are you doing the brake bleeding by yourself? Or do you have a helper?
You should have two people performing this task, one pressing and holding down the brake pedal, then opening the bleeder, then close the bleeder while the pedal is still down, then pump and hold down and repeat the process. What I read, it sounded like you were trying to do this by yourself… just asking.  If you are doing this by yourself, then you’ll keep pulling air around/ through the bleeder because your not sealing off the system at each pressure change. Teflon tape should never be used around the bleeder.
I also wanted to make sure that your bleeder is facing up.. I heard of some trying to bleed their system with the bleeder facing down. I don’t want to come across as being condescending, just trying to cover all angles to help resolve the issue.

glhx:
Yeah, I’m bleeding it myself.

I have long runs of 3/16” tubing tightly sealed to the bleeder screw.
They run the length of the car back into the master cylinder.

When you bench belled a master cylinder. You run the master cylinder outlets back into the reservoir.

I’m doing the same thing. I’m just doing that with the entire braking system.

I should be able to pump as many times as I want and the air finally bleed out of the whole system.


The Teflon tape was only used to seal the threads with the bleeder screw open. And just for this style of bleeding. Because a loose screw can pull air back into the threads. This Teflon tape prevents this. Toy don’t leave the tape there permanently. It’s just for this style of bleeding for air creeping into the threads. Some people use grease to do this but grease is ineffective. This is a very solid way to bleed a system. Probably the best way but not commonly done because it uses a lot of extra fluid to fill the hoses. I’ve used it many times. It’s a sure way to get every little particle of air out. Only a pressure bleeder might be better. It’s basically bench bleeding the whole car instead of just the master cylinder. Same concept.

However……I added a bleeder screw that was drilled out. This closed off the threads and no tape was used. It just allowed free flow out of the screw into my long run of 3/16” tubing. I only did this and got rid of the tape, so I wouldn’t have the tape to blame. The threads were sealed tight. This 3/16” hose was sealed tight.

I also did this with a 2 person style. The normal way……
Just to prove it’s air coming in from somewhere else.
And here…..right here. Shows the problem. The air still crept in even with the normal 2 person style. I still had the hose sealed to the bleeder screw so I could watch the air come out. This shows for certain there is air coming in the system. I just don’t know where yet.

There can be only a few places.
The passenger side rear line with its 2 connections.

Or the 3 seals in the caliper.
The parking brake seal on the shaft.
The piston ratcheting o ring
Or the main piston seal.

It’s a complicated caliper

I haven’t taken the caliper apart yet. Often times the rebuild these and leave the pits in the caliper. Sometimes they leak fluid.

But these were 2 new calipers from oreilly. They shouldn’t leak.

I’m just seeing if anyone else has had this problem specifically. I’ve seen the Eldorado guys have it a few times but nothing really came of it.

I’ve also seen where they put front calipers on the back and get rid of the parking brake all together.
I’ve got a good parking break adjustment. I just can’t get the system to not pull air every time I step on the brake 6 times.

tinpusher:
Ok, now I see what you’re doing…I didn’t understand the drilling of the bleeder, now I do, never did it that way.

It doesn’t make sense that you’re pulling in air and not leaking fluid. Once you push on that pedal, your fluid pressure would be several hundred psi and fluid would be spraying everywhere.

I have the stock 4 wheel disc brake set up and only had one issue with the MC. Maybe do a gravity bleed over a few hours, then close the system to see if it makes a difference?

tinpusher:
I know that your MC is new, but you might want to pull it away from the vacuum booster enough to check for dampness. No need to disconnect any lines to check. I haven’t had much luck with the reman stuff. I remember when we would just rebuild these ourselves with a hone and rebuild kit.

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