UniqueTII
Well-Known Member
I just installed a Powerstop Z36 on my 2015 XL and I cannot get the brake pedal to stop sinking to the floor. I didn't crack the system at all, just retracted the pistons with channel locks (bleeders closed) and replaced everything as normal. As soon as I went to test the truck out, the pedal was mushy and would creep toward the floor. I bled about 2 gallons of fluid through it, including while cycling the ABS pump with a Snap-On scanner. Nothing has helped at all.
I assumed it was the master cylinder, so I removed that to look for leaks and found nothing. After that I reinstalled it and bled it, then capped off the ports to test it. The pedal stayed firm even with the truck running, so I don't think that's the issue. They're on back-order everywhere, but I did find a used one on eBay that was already on the way.
The next step was to disassemble everything to make sure the caliper pistons moved freely, the sliders were okay (I cleaned up the rears a bit), and to open the bleeders while retracting the pistons this time. No help. After that, I pinched the lines with vice grips and narrowed the issue down to the front. With both front lines clamped, the pedal firms up pretty well. If I remove either of the vice grips, it sinks again (even if pumped a couple of times). We did another bleed on the fronts tonight using a standard 2 person method and that didn't help.
I didn't see any flex in the brake lines, but I have a new set on the way anyway. What the heck else can I do?
I assumed it was the master cylinder, so I removed that to look for leaks and found nothing. After that I reinstalled it and bled it, then capped off the ports to test it. The pedal stayed firm even with the truck running, so I don't think that's the issue. They're on back-order everywhere, but I did find a used one on eBay that was already on the way.
The next step was to disassemble everything to make sure the caliper pistons moved freely, the sliders were okay (I cleaned up the rears a bit), and to open the bleeders while retracting the pistons this time. No help. After that, I pinched the lines with vice grips and narrowed the issue down to the front. With both front lines clamped, the pedal firms up pretty well. If I remove either of the vice grips, it sinks again (even if pumped a couple of times). We did another bleed on the fronts tonight using a standard 2 person method and that didn't help.
I didn't see any flex in the brake lines, but I have a new set on the way anyway. What the heck else can I do?
