I recently installed the Mopar big brake kit on my 2009 JKU-R, and have had nothing but problems ever since... I bench-bled the master cylinder until there were no more air bubbles coming through the lines (pretty standard stuff), and replaced the booster, master, front rotors, and calipers without much issue. The problems came when it was time to bleed the brakes and actually put them into service. When I bleed the rear brakes, the pedal stops solid about 1/2 way down - it will NOT go all the way to the floor? When bleeding the fronts, however, the pedal goes all the way to the floor as you would expect. The real problem is, the brake pedal feel is now terrible and it takes about 2/3 of the pedal travel before anything happens at all? And worse yet, often times while sitting there with light pedal pressure applied, say at a stop light or something, the pedal will actually drop away from my foot and I have no brakes at all until I pump the pedal???? Just looking for ideas on things to check, tests to run, etc? Oh, and I've got a buddy that has the Chrysler scan tool to perform the ABS system bleeding, and we did that as well with NO change... Thanks in advance for any help.

 

I installed the Mopar BBK myself, and had none of the problems that you described. What I did differently was that I used a brake bleeder vacuum pump to bleed the brakes. I also did not perform the scan tool ABS system bleeding since it is not needed.

Use a brake bleeder vacuum pump starting with the furtherest wheel from the master cylinder and work your way forward as the instructions say. It sounds like you have air in the lines, where your current method is not working.

 

This is one of the reasons I went with the Dynatrac ProGrip brake system. No opening of the brake lines.

 

You still have air in the lines. Don't try to bleed using the old pump & squirt method. Ideally they should be bled using a pressure bleeder, as they are done at the factory. You can get one relatively inexpensively from Motive. https://www.motiveproducts.com/colle...-mopar-bleeder

The cheaper, but a little less effective alternative is to vacuum bleed using a Mity Vac as noted above.

It is a rare possibility you may have gotten air into the ABS motor/pump unit (module). If after you've pressure or vacuum bled the system there is still some question, take it to your dealer and have them bleed the brakes using the Starscan ABS bleed routine.

 

After the upgrade did anyone have issues with the master clutch cylinder going ?

I changed the brake kit and added a small reservoir and the master clutch cylinder went after a 500 miles, I changed and didn't get 500miles on it and it's gone again. Is my reservoir too small ? Could it be getting too hot ?

 

 

I think you have inadvertantly posted this in an older non-related thread. You should go in to the Modified sub-forum and create a new thread.

 

I currently have the same issue and wanted to know how or if you fixed the problem.

 

Did you install the J8 brake booster as well as the new MC? When I installed that kit, I had all sorts of issues with that brake booster. I lost the new Mopar MC to jammed piston, then I almost immediately blew seals in brand new Crown replacement unit (couldn't buy the J8 MC separately as a replacement). After that I went back to my factory booster and MC ('13) and have had no issues. I was not about to test out a 3rd brand new MC. I swear it was an issue with the larger booster though others seem to run that with no problems.

 

I’m still running stock MC. Thought of going to bigger one but seems like it’s not the solution right now.