1990 Ranger 4x4 Brake Problems

[John RTC Engine Lab]

The brakes on this thing are crap. The front disks decided to slowly apply themselves and lock up while I was on the freeway.
I installed new (rebuilt calipers, master cylinder and all the brake hoses). Bled the master cylinder, bled the calipers. The pedal travel is halfway to the floor. I adjusted the rear brake shoes and tried to bleed them but no real pressure coming out. The rear brakes won't bleed properly, and only a little fluid is coming out. Then I see the ABS control block inside the frame. That should only limit the pressure to the rear brakes. I have very little pedal. It brakes but halfway to the floor. I put a pressure bleeder on it and pumped a quart of brake fluid through the front calipers but still a low pedal.
What am I missing?

John

 

[Uncle Gump]

Crack the rear line at the master and push the pedal down. Does it have proper flow there?

If yes... two things come to mind. The RABS Valve is not allowing fluid to flow properly... or the rear flexible hose isn't letting fluid flow properly.

As for the low pedal... what does it do without the engine running ? Without the vacuum assist... brake pedal should be firm close to the top of travel. If still low... it's likely trapped air or rear brake adjustment.

 

[85_Ranger4x4]

New calipers are mounted with the bleeders to the top?

If you get the lefts and rights turn around they will mount but will be upside down on the wrong wheel and will never bleed.

 

[Uncle Gump]

Very true...

I've never done it myself... but I've heard it happening a few times.