Disk brake help

30th6 · May 29, 2015

I replaced a rear caliper and line on my jeep and now I can't get a pedal.
I've bleed the rear calipers for about two hours.
I haven't seen any air come out in at least a hour of bleeding,but I did run the master cyl dry once.
The pedal goes all the way to the floor but I've seen all the calipers working when the brake pedal is applied.
During bleeding about half way down on the pedal stroke it quits pushing fluid out the bleeder.
It will not stop the rear wheels on lose gravel but will lock up the front.
Any input would be much appreciated.

Joe Eck

Chuck19 · May 30, 2015

Sounds like you have air in your master cylinder bleed it and see if that helps !

zukimaster · May 30, 2015

Make sure you didn't put the caliper on upside down, the bleeder will always be on top. Just something to check.

30th6 · May 30, 2015

I'll try and bleed the master cylinder , the caliper is on with bleader at the top.

Joe Eck

bgredjeep · May 31, 2015

Did it work before replacing the caliper?

30th6 · May 31, 2015

Yes it worked fine

Joe Eck

gubni · Jun 1, 2015

Did you use a jb6 or jb7 caliper? Jb7 may be too big for your mc. Why did you replace the caliper? Did you bleed the front also?

30th6 · Jun 1, 2015

The caliper was dragging , I replaced it with the same (looking) caliper off early 80s 3/4 4x4 front Chevy truck.
I bleed the front with no improvements .
I'm gonna try bleeding the master today.

Joe Eck

30th6 · Jun 1, 2015

I bleed the m/c installed a new m/c reblead everything , used a Mitty vac, and now my brakes are worse than ever.
Guess I'll try a dodge 2500 m/c tomm and hopefully it will fix my issue

Joe Eck

30th6 · Jun 2, 2015

I put a dodge 2500 m/c on today and gutted the factory proportioning valve and now I have front brakes but very little back brakes.
There is very little fluid coming out of the rear calipers when bleeding them.
Any body have any tips that could help me out?

Joe Eck

Beerj · Jun 2, 2015

Used to have a helluva time bleeding brakes until I got a vacuum bleeder. They definitely make life easier.

30th6 · Jun 3, 2015

I tryed a mighty vac but it just kept sucking the line dry. The mc wouldn't let me vacuum blead it or gravity bleed it

Joe Eck

gubni · Jun 3, 2015

The JB6 and JB7 look similar. The piston size for JB6 is 2 15/16 and the JB7 is 3 5/32. That's the first thing I would check. Also take the other one off and check it. It may be mostly stuck open. It's always good to replace them in pairs.

Use vice grips to clamp off the front and rear brake lines - pedal should move maybe 1/2" then loosen them one at a time to see how it goes. You can also use this technique on all 4 corners to narrow the problem down. Feel free to contact me for support as I only visit here on occasion.