Nissan Versa Brakes

[michael]

Alright it’s been a while since I’ve had to ask a brake question but I’m overly frustrated with this vehicle, so I got a 2012 Versa in the shop. The pedal was going to the floor but the brakes were working. It would feel a little light but once the pedal traveled half way it lost all pressure and went to the floor but the braking didn’t change. The master was leaking out he back into the brake booster, replaced the booster and master. Bench bled the master 4 times (twice with a kit) and went through 6 quarts of fluid bleeding brakes (insane I know). Pedal didn’t change. Plugged both the old master and new one to ensure the diagnosis was correct and I didn’t just waste my time and the old master did infact not hold pressure but the new one does. Called a Nissan Tech who said every Nissan hes done a master on he had to bleed the ABS. I’ve never had to bleed the ABS on a vehicle after changing the master but said screw it and got my hands on a scanner that did bidirectional. The scanner surprisingly (a matco) could control the ABS valves individually but didn’t have a function to bleed the ABS. We manually opened and closed the valves trying to manually bleed the pump and when we closed the valves the pedal would raise slightly and as soon as we opened it or backed out to close another valve the pedal would go away again. No faults on the vehicle for anything and no leaks at the calipers, lines aren’t swelling, and I’m not getting any air out of the brakes. This brake booster isn’t adjustable so I can’t change the pin length. Does anyone have ANY possible ideas as to what’s going on with this vehicle or tips I may try. I’m driving myself crazy over this car and it’s been in my shop for a week.

PS pumping the brakes doesn’t increase pedal height or feel.

EDIT forgot to mention drum brakes on back were adjusted (pads are well within spec).

Topic

[none]

That scan tool may not have enough in terms of functional tests and procedures. I sometimes have to bounce between a Snap On scanner and an Autel because one is missing a function that the other has. There’s one other option you can look for in absence of an ABS bleed procedure. I used to do my brake flushes and bleeds with a pressure bleeder. I never had to give any regard to an ABS procedure with it. If you can find a pressure bleeder, it’s worth a shot. This is far left field stuff next, but if somebody topped off the brake system with something other than brake fluid, it would mean that there’s other seal damage in the ABS module or all the way out to the caliper piston and wheel cylinder seals. Did you see anything damp or wet at the calipers or wheel cylinders?

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