Brake Problem

[RonH]

My son told me his brakes didn't feel right so I checked the fluid and noticed brake fluid in the engine compartment, even squirted on the hood pad. I replaced the Master Cylinder and bled all brakes. The pedal seemed to pump up until the truck was started then the pedal went to the floor. Next I replaced the Booster but this hasn't solved the problem. The pedal still pumps up when the engine is off but not when it is running. Can anybody give me an idea what to look for? Thanks

 

[Hopman]

Gasket on the cap? Busted hard lines?

 

[adsm08]

Air in the lines.

Did you bench bleed the master cylinder? Sometimes air can get way back up in the lines, especially when the MC comes off. If you didn't bench bleed, take it back off and do that, then bleed them again going RR wheel, LR wheel, RF wheel, LF wheel. Make a couple rounds using that pattern. I had to do that when I replaced the MC on my Nova.

If the pedal goes right to the floor when the engine is running that means that the booster is good and working.