Hello everyone.. I have a very bizarre situation on my hands. 2006 H3 with a very spongy brake pedal. Researched it and it sounded like it was the BPMV?master cylinder at fault. $800 later after replacing the entire unit the brakes are the same-- pedal sinks to floor when driving but feels great when the car is stopped. I am completely stumped! I performed the automated bleed procedure twice with a scan tool and bled the system the traditional way. Im not getting any air at any of the wheels, I even tried cracking the lines loose at the master while an assistant holds the pedal down. Also when stopping , it kind of seems like maybe the front only is working because the truck kind of takes a nose dive. It seems like theres still air trapped in the system..but why is the pedal good when stopped and the engine is running??

 

No mention of brake pad wear? Any ABS faults?

 

Check your front wheel hub bearings, Jack it up and grab the top and bottom of the front wheel and wiggle back and forth, if it moves at all the bearings are bad.
Had the same issue.
The rotor wobbles in the brake caliper and pushes back the pads as you drive so when you push the brake pedal the first few pumps are getting the pads back to the rotor then it squeezes for the stop.
Try this.....when you come to a stop after driving for a few minutes pump the pedal as you come to a stop. If it pumps up from the first pump when it goes to the floor to a regular pedal feel, you have a bad front wheel bearing ...or both.
Mine did this for both bearings at different times, never set a code.
Only the second time I knew what it was right away.
They are not to hard to change.