Rear brake issues

[Rugby]

Today I replaced the rear brakes on my 87 gn. I put in the 85 s10 manual wheel cylinders with factory shoes.

The car can't hold 1psi of boost before the tires want to spin.

I have vaccum booster and alum drums. The shoes have been adjusted with a slight drag on the drumm.
The wheel cylinders were a pain to bleed. It would push out a lot of fluid like normal then it would just dribble out.

What to check next?

Brandon

 

[PSID6]

I recently did the same thing. I believe you need to bleed the brakes again. Trust me I feel your pain, the rear bleeders are a total PITA! Start with (from the drivers seat) the RR then LR then RF and at last LF. I did mine 3 times before I could brake boost to a respectable level. Went from 2lbs to 14 lbs before she breaks loose now. Good luck!

 

[Rugby]

I am reading about the prop valve and resetting it. Ia m going to give that a try and re-bleed them in the next couple days.

 

[turbo nasty]

Word of warning the bigger rear wheel cylinders.....panic stops and especially in the rain the rears will lock up on you and bad things happen when the azz comes around when trying to stop. Been there done that.
And I agree with the re bleed and you may have to get something to keep the plunger in on the pro valve. It popping out with the psi difference when the rears are open will hamper the bleed process.

 

[Rugby]

Everything I have read about says when you put the long shoes on it causes the rear end to lock up. Right now they will not lock up on owl shI..

 

[Fast4Ward]

Bleed then bleed and bleed again and then gravity bleed and regular bleed to finish. My car has hydro brakes with sten cylinders and long shoes. It holds alot of boost.

 

[Nick Micale]

If your master cylinder has air in it, or not been bled properly, you will never get the all the air out of the rest of the system.

I have changed many master cylinders without never having to bleed at any wheel, and in 25 years with these cars I have never "reset" a prop valve?

 

[Chuck Leeper]

I replace the "prop valve" w/ a Wilwood adjustable. Want more/less bias, adj the valve.
I also have a brake psi gauge. Amazing what one sees w/ some combos of m/c sizes, rotor sizes, prop valve settings.

 

[PSID6]

If your master cylinder has air in it, or not been bled properly, you will never get the all the air out of the rest of the system.

I have changed many master cylinders without never having to bleed at any wheel, and in 25 years with these cars I have never "reset" a prop valve?

What is the procedure to bleed the Master cylinder? Never done that,maybe I could get some more boost!