Hi All...My Wife's 2012 JKU Rubi is having brake issues. I replaced the brakes a few weeks back. Now you have to stand on the petal and mash it to the floor to stop the Jeep. Yes, I just pressed the calipers back and installed the new brakes. We replaced the brake fluid and bled the lines till they ran clear. I put the clear tube on the bleeder nipples and saw no air coming out. Bled the lines multiple times after this. I then took it to a shop where they cycled and bled the ABS multiple times, did a manual bleed on the brakes and did a pressure bleed on the brakes. He tested the Master Cylinder and thought it was bad and replaced it, but that did not resolve. We even replaced the new master cylinder with another new one and that did not resolve either. The jeep is throwing no codes for brakes or abs. Where else can we look?

 

Not likely, but I wonder if any of your calipers are seized? So when you push the pedal in, the pistons are not actually moving?

 

Having gone through so many MCs now, and all the bleeding and cycling of the ABS, I'm wondering if the problem lies in the booster. That would have to be dang coincidence though for that to start going bad right after you did a basic brake job.

 

Check your front rubber hoses. I have a 2011 sport and was having the brakes pulling to the left when I hit the pedal hard. It turn out to be both front hoses were plugged where the metal piece on the hose bolts to the frame. Brakes feel great now. I replaced calipers, pads, and rotors, before I finally did the hoses. The brakes would bleed fine but still had the pulling problem. When I took the right side off I couldn't blow through it at all. And the left side was just a little bit of air going through it. Hope this helps you.

 

What kind of pads did you use? They can make a difference in brake feel and performance.

 

Did you also try to change the brake pad after changing the master brake? Because the peak of any brake issue is the master brake. Maybe the brake pad is not the one meant for the jeep or if you can try to change the cylinder of the 2 front tires maybe they are not grabbing well again.

 

Not sure but you say "mash it to the floor"? That tells me the pedal goes all the way down which is most likely a leaky master cyl plunger or air in the system. If that mash statement is to describe the effort/frustration and it is simply not grabbing I would say the brake linings are too hard or incompatible with the discs. Did you try and use carbon fiber pads? or stock pads? Did you slowly drive around for a few miles with very little braking effort to bed the pads in?

 

So everything checks out. Brake booster, pads, calipers, manual and power bleeds. He is ordering a new MCU/ABS module for it. Hope to heck that fixes it and he is not just guessing. 900 bucks installed.

 

Thanks for the update. Several of us following along so will be curious to hear if that was it or not.

 

Please do let us know what happens. One other thought, sometimes the caliper piston ends up with a ridge and when you push the piston back in with new pads it now hits the ridge when trying to stop.