1980 CJ Brake Problems

I purchased a 1980 CJ5 a few months back and have been slowly performing needed maintenance. The brakes were terrible and I had what I call "washing machine" feel in the steering wheel when I applied the brakes. After inspection, I noticed that both front rotors were warped and the rear drums were worn beyond repair. Everything was pretty rusty. The PO mentioned he had problems with the back brakes in the past and had installed a new master cyclinder, although it did not appear new. I have installed new flex lines, new calipers, new rotors, new pads, new drums, new cylinders, new shoes, as well as all new springs/etc. I've manually adjusted the rear brakes and the parking brake is functioning again. I have bled the brakes multiple ways, one wheel at a time, and then one side at a time. Been through this multiple times. I've used a rubber mallet to tap on the cylinders and calipers to dislodge air bubbles. I don't see any leaks and have no fluid on the floor. I have clean fluid coming through with what appears to be no air bubbles. The pedal remains squishy. It has firmed up maybe slightly, but not much. I have no back brakes, when I pull off the drum I do not even see the cylinders move. I have not tried the fronts yet as I still have it up on jack stands in the rear. Any pointers? Any ideas? Is it possible to have a bad master cylinder and still be able to see good fluid flow when bleeding? Does the proportioning valve have anything to do with it? Thanks for any advice. I know bleeding brakes is a pain, but this has me stumped.

 

Sounds like you still have air in the brake lines. The usual procedure is to bleed the longest line first which would be the right rear, then the left rear, right front, then left front. When the fluid is drained all the way to the proportioning valve, it takes a while to get all the air out.

 

If you continue having issues after bleeding the brake system as mentioned by Jim inspect the MC. If the MC was installed without proper bench bleeding the issue may be there unless the MC is also failing/defective.