Please advise!!
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Please advise!!
Hey guys got an 89 f350 with a cummins swap and the brake pedal goes almost to the floor and I coast to a stop. I literally have to manually shift my automatic into neutral because the brakes can barely hold the truck at a stop. Front brakes done last year, rear brakes drum to drum, vacuum booster, master all done last week and the system was power bled at my brother's shop. Is there any chance there's a vacuum issue? I know that the cummins pump is known for leaks but everyone I talk to shoots me down saying the pedal would get harder, but what if it's such a bad leak it all just goes away? Also the abs valve under the cab was bypassed? I'm ready to rip my hair out and go ballistic on this truck please help!
Last edited by Joe_fummins; Dec 3, 2014 at 08:18 AM. Reason: Forgot info
Senior User
Joined: May 2014
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From: san jose
Check for air in the lines. Then the level (all mentioned above) then k would make sure the caliper is in working order. If not possibly one of the lines has a kink or bend not allowing proper pressure to the brakes.
FTE Legend
Joined: Jun 2006
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From: Ottawa, Ontario
Rear brake drums out of adjustment. These need to be setup so the shoes are just off the drum otherwise you will have excessive peddle movement.
Other possibilities are improper bleed procedure, it has to be done rear to front starting from the passenger side rear and including the proportioning valve which means 5 bleed points.
Other possibilities are improper bleed procedure, it has to be done rear to front starting from the passenger side rear and including the proportioning valve which means 5 bleed points.
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Thanks
Hoses are all new, drums are adjusted right, brother is a mechanic, bled in the correct order, this is why I'm so confused
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Cargo Master
Joined: Jan 2004
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From: South Dakota
If the rear brakes are not adjusted up tight enough pumping the brake pedal rapidly will bring the pedal up, just until you let off the pedal for a brief time of course, do this as a test. YES I read what you said under #7, but I'd check anyway.
If you have some pedal, which you do, a little air will probably work it's way out, so I don't think that's it.
Otherwise I'd say a bad master cylinder, or something with the linkage going to the master cylinder.
If you have some pedal, which you do, a little air will probably work it's way out, so I don't think that's it.
Otherwise I'd say a bad master cylinder, or something with the linkage going to the master cylinder.
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Ok
Thanks guys, adjusted drums to the point where with the wheels off we could barely spin them, pedal was ok for awhile and then all of a sudden got soft that's why I redid the rears, it seems to be getting worse too
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Correction
Pedal was fine after replacing the front pads and calipers last year, then about 2 months ago the soft pedal issue came up, so then I replaced master, then booster, then rebuilt rear brakes, and nothing fixed it
Cargo Master
Joined: Jan 2004
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From: South Dakota
I would check the linkage from the brake pedal to the master cylinder. I read about the firewall where the master cylinder mounts getting weak, but I never experienced it. Also some of the linkage in the pedal area, never experienced that either just read about it. I'd check those to begin with.
Cargo Master
Joined: Jan 2004
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From: South Dakota
Certainly could be. The replacement you bought could have been bad out of the box, especially if it was a rebuilt, not new.