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super soft brakes after homer brake swap

2fast242gt

Do you have a cobalt?
300+ Club
Joined
Nov 2, 2005
Location
appleton WI
The system was dry over winter. Anyways I have a new master and low mikae calipers on the car. With my power bleeder hooked up I get clean air free fluid from each caliper. The pedal is spongy at best with the car off. If the car is running I can press the pedal right to the floor. Thoughts? I bleed it for a good hour. I heard air may be trapped in the reae proportioning valves?
 
You sure the junction block seals are good? No leaks anywhere?
Ditch that power bleeder, you'll never get all the air out of it with one of those. It took 6 or 7 rounds of bleeding with pedal only to get mine done.
 
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Yeah zero leaks and I tried the two man method first. It all worked fine before so I'm assuming the junction block is good.
 
It has sat open though, potential rust in the system might have torn seals. I'm guessing there's air still in the system though. Bleed with the rear end higher.
 
Have you bled it right at the master? If the whole system went dry you need to bleed it at the master first.
 
Just threw the master on and lightly pressed the pedal till it was Pushing fluid. Then Began normal pumping I'm going to bleed the master seprate now and see if there's air trapped.
 
You are bleeding like this:

Bleeder closed
Pressure on pedal
Crack bleeder
Pedal goes to floor
Keep pedal on floor
Close Bleeder
Let pedal come up

If you're "pumping" the pedal with the bleeder open, you're doing nothing but sucking air back into the system.

Also, on a system that has been dry, I've had good results with cracking all the bleeder screws open at the same time and just letting it gravity bleed for awhile before you deal with pumping the pedal.
 
You are bleeding like this:

Bleeder closed
Pressure on pedal
Crack bleeder
Pedal goes to floor
Keep pedal on floor
Close Bleeder
Let pedal come up

If you're "pumping" the pedal with the bleeder open, you're doing nothing but sucking air back into the system.

Also, on a system that has been dry, I've had good results with cracking all the bleeder screws open at the same time and just letting it gravity bleed for awhile before you deal with pumping the pedal.
That's exactly what I did yes. Ill try cracking them all.
 
Yeah, crack them open, drink a couple beers, close all bleeders, then try it. Also as homer suggested, raising the rear may help work out air bubbles back there.
 
You sure the junction block seals are good? No leaks anywhere?
Ditch that power bleeder, you'll never get all the air out of it with one of those. It took 6 or 7 rounds of bleeding with pedal only to get mine done.

It worked great for me when I replaced the 240's entire front hard and soft lines and the rear soft lines.
 
If you floored the pedal while bleeding and it's an old master you probably tore up the seal on the plunger.
 
Ugh two questions I answered already... thanks for the help guys ill take all the advise and try the other methods and see what happens.
 
Yeah, only reason I asked is cus the way you bled the master first isn't how I was taught to do it. Not saying it's wrong but just cus fluid comes out doesn't mean there's no air in it
 
Ok so I just bled the master basically bench bled it but on the car. Then did a rebleed of the entire system same results clean air free fluid comes from each bleeder... but I have a spongey pedal! I looked again for leaks and everything is dry. I'm at a loss... I was told the rear proportioning valves are known for trapping air... I jacked the rear up to try and help that but that didn't work either.
 
Ok so I just bled the master basically bench bled it but on the car. Then did a rebleed of the entire system same results clean air free fluid comes from each bleeder... but I have a spongey pedal! I looked again for leaks and everything is dry. I'm at a loss... I was told the rear proportioning valves are known for trapping air... I jacked the rear up to try and help that but that didn't work either.

What calipers? And what size pistons? Tooooo big and you'll have mushy pedal.
Stock is 4 x 1.5" pistons.
I did Willwood Superlites on a Saab 900. 4 x 1.75" and stock was 2.125" one direct/and effectively the onther pad gets the reaction force of the fame thing, so basically 2 x 2.125"

Do the total area.. 4x 1.75 was waaay too much..

My experience says you can go up about max 1/8" on piston size or 4 x 1.625 to have a decent pedal. So 4 x 1.625> More and you're fuxxored.

So what piston sizes?
 
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