Losing Brake Pedal Pressure

[rjr]

There was recently a GM "recall" notice re the 2015 brakes requiring extra pressure.

 

[Rocket Man]

There was recently a GM "recall" notice re the 2015 brakes requiring extra pressure.

Interesting. But this is an 05.

 

[jcb2]

Howdy,
My '05 Yukon XL has an issue where the brake pedal loses pressure when at a stop. To the point where it starts rolling through the brakes and the "Service Brakes" alarm sounds. I recently changed all the steel brake lines, master cylinder and bled the lines a couple times.

That thread is here: https://www.tahoeyukonforum.com/threads/mushy-brake-pedal-after-new-brake-lines.110137/

I haven't had a chance to look in to it too deeply yet and I have not seen any puddles of brake fluid on the ground either. So, I'm a little stumped on where to start. Any ideas?

Thanks in advance,
Lord Snax

Sounds like the master cylinder is passing. The fluid pressure is bleeding back to the low pressure side. I know you just replaced it, but I bet it’s bad. With no signs of leakage, that has to be the problem.