Brake problems

[cdtx_2011]

When I took ownership of my '88 MJ the brakes were 80% non-functioning so I started throwing parts at it in good faith. I've followed every method of bleeding the brakes that I've found on here and nothing is working. The front brakes don't seem to have any pressure when I bleed them and the pedal doesn't go further down when you open the bleed valve like it does when you bleed the rear. I have not yet purged the lines clean, and I haven't taken apart the prop. valve to see if it's stuck in bypass mode (I know the light on the dash should tell me this but I haven't looked either).

 

Upgraded to a used WJ master cylinder/booster

New Front calipers/pads

Rear cylinders/shoes, springs, etc.

New front flexible brake lines.

 

Should I try an XJ prop valve swap and delete the bypass line and load senor? Is it a simple plug and play?

 

Any ideas?

[89 MJ]

I know you said that you tried every method of bleeding, but I just want to double check that you did the bleeding procedure for the prop valve. 

Did you put in a new master cylinder? Are you getting fluid out of the fronts? Did you do new hoses in the front? If the hoses are new, I think I would look at the prop valve.

[cdtx_2011]

Yes, Master was bench bled and all was good. New front lines. Prop is the next step maybe?

[89 MJ]

I think that’s what I’d check out next. Make sure there is good fluid flow coming out of the front line when you pull it out of the prop valve. 

[Pete M]

I had a bad combo valve (the thing up front that looks like a prop valve) cause me to lose years off my life.  it moved for bleeding the rear and the shuttle refused to go back and I couldn't bleed the fronts. 

[PIKE]

Make sure calipers are oriented correctly with bleeders at the top. There is a left and right.

 

Please don't ask me how I know this.