Surging while braking

[MasterJ220]

98 4x4 2500 5.7liter While braking it will surge forward (need to brake harder) and the oil pressure drops slightly. Owned for 4 years with no trouble. 120,000 miles. Any help would be awsome. thanks.

[taillight]

Check for vacuum leaks. Check brake booster for leaks. Disconnect brake booster vacuum hose and plug hose. Take for a drive. Watch brakes. If no surge, bad booster. Remember you now do not have power brakes.

[MasterJ220]

what do you mean i don't have power brakes.

[777stickman]

Originally Posted by MasterJ220

what do you mean i don't have power brakes.

What Taillight means is if you disconnect the vacumn source to the power brake booster you won't have power brakes. You'll still have brakes but it takes much more pedal effort to get it stopped. Try it in a parking lot with lots of room.

Also can you be more specific about the surge you're feeling. Does it feel like the brakes are giving up or is there an increase in engine rpm's that's causing more braking effort?

[MasterJ220]

increase in the engine

[liloldbeater]

My 98 350 vortec Z71 was having the same problem and I cleaned out the throttle body (it was all carboned up) and the problem was gone. Good luck, oh and by the way dont get cheapo autozone throttle body cleaner it doesnt work, get the good stuff the first time.