Brake pedal goes to floor.

[rcbeau1911]

2006 yukon xl 2wd 5.3

Normal driving brakes are fine but sitting still and pressing pedal it will slowly go to the floor. As well as when slowing down coming to a stop it will slowly go to the floor.

Turns off stabilty control as well as tells to service braking system.

Once you roll away from stop I can tap pedal and it comes back and lights go out.


I thought it may have been abs or the wheel sensors so I removed the 60amp and fuse under good the problem remains.

Any other ideas? I'm leaning toward MC

 

[southboundchicken]

Sounds like your master cylinder needs to be replaced

 

[TTR_48]

Ditto ^^^

 

[rcbeau1911]

Fluid is nasty Damn near black. Anything else to test before I replace parts.

 

[TTR_48]

My wife's car did the same thing about 2 years ago, ended up being the MC. I would replace it and do a whole system flush which sounds to be needed anyway due to the color. When the seals start to break down on the MC, the system can loose its pressure. Dirty fluid is also bad for everything. But I would start there, only round $60-$70 on rock auto.