Pulsing Brakes

[TTipswprd]

ya it sounds like a hissing sound when i step on the brakes and if im hard on em then my truck pulls to the right.

[cougar]

TT, most likely the ABS valve. I'd vote that over the master cylinder. BTDT.

If the dump valve is leaking, the you probably could pump it up. If the dump valve is stuck open , then you would have mushy brakes all the time.

If you are hearing a hissing sound, then the booster is possibly leaking. Pulling can be an out of adjustment brake or contaminated linings.

[TTipswprd]

so can i fix the leak or do i need a new booster?

[cougar]

The booster is not repairable. A leak check can be performed to verify a problem. Using a hand vacuum pump. see if the booster will hold vacuum. They say no more than 1"hg drop in 15 seconds is OK.