Vacuum Pump..Stiff pedal

Reply Subscribe

Thread Tools

Search this Thread

Oct 4, 2006 | 06:05 PM

KillerF250

Thread Starter

New User

Joined: Sep 2004

Posts: 22

Likes: 0

From: Halifax NS

Vacuum Pump..Stiff pedal

My brake pedal is intermittently getting stiff, how do I test the vacuum pump or basically, what kind of PSI should it have at Idle?

Thanks in advance,

G

PS: Anything else it could be, it has new calipers and rotors and there is no air in the lines.

Oct 4, 2006 | 08:17 PM

cujo8

Posting Guru

Joined: Mar 2006

Posts: 1,118

Likes: 0

From: Williamson, NY

Sounds like there may be a problem with your proportioning valve possibly? I read a thread recently that stated you need to push or pull the little valve on the proportioning valve when you bleed the brakes on these trucks. If I remember right you need to pull the valve on F250 and larger and push the valve on the smaller trucks like F100-F150.
It may be related to your brake booster as well, but there is not a vacuum pump involved here, The vacuum source for the brake booster comes from a port on your intake manifold and the vacuum is generated by the running engine.

Last edited by cujo8; Oct 4, 2006 at 08:23 PM.

Oct 5, 2006 | 04:46 AM

SRD4X4

Posting Guru

Joined: Oct 2004

Posts: 1,008

Likes: 0

From: Annapolis,MD.

Assume it's a diesel,vacuum should be 15-21 in. at idle (depending on altitude)from the pump.Remove hose from booster and just hook gauge to it.

Oct 5, 2006 | 03:31 PM

KillerF250

Thread Starter

New User

Joined: Sep 2004

Posts: 22

Likes: 0

From: Halifax NS

My apologies everyone, normally I’m in the “Pre-Power stroke” forum so I should have mentioned it’s a Diesel, thanks for the #’s, I did some other tests and pretty much have determined for sure it’s the pump but I’ll triple check with the gauge.