Lost braking power
Thread Starter
|
Senior User
Joined: Feb 2010
Posts: 161
Likes: 0
Changed out brake booster and brakes are acting the same. its like they intermittently work. Brake peddle is hard and truck slowly stops. Like manual brakes. Gonna hook up vacuum gauge directly to vacuum pump and see if it consistently pulls vacuum. Cant think of anything else.
Junior User
Joined: Feb 2015
Posts: 77
Likes: 0
I'm hoping bumping this thread will help spur a solution. I am now having the same issue. Hard pedal and ya gotta stand on it to get it to stop. I plan to test a bunch of things but, don't have a lot of time and it's my daily D.
Postmaster
Joined: Dec 2011
Posts: 3,860
Likes: 7
First, make sure you are getting vacuum to the booster. Let it idle, pull the line off, and put your finger on it.
If you feel it sucking, you should be getting some boost. If not... you've either got a vacuum leak or failed vacuum pump.
If you feel it sucking, you should be getting some boost. If not... you've either got a vacuum leak or failed vacuum pump.
Junior User
Joined: Feb 2015
Posts: 77
Likes: 0
Checked it this morning. Pulled the vacuum line off the master cylinder drum and am getting suction. However, it doesn't seem all that impressive. It will stick to my finger but, comes off easily. I first noticed this 2 weeks ago when I removed my vac pump to change my fuel pump. It eventually regained power brakes within 20 mins. Been fine ever since. Then, on the way home from a camping trip (while towing), I went to make that last turn off the highway and had to stand on it to slow.
Junior User
Joined: Feb 2015
Posts: 77
Likes: 0
Quick update. Drove to work this morn and noticed I had a good 75% power brakes on the first pump. Then it goes hard and difficult to brake. I assume I'm building just enough pressure/vacuum to get one good push.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Junior User
Joined: Feb 2015
Posts: 77
Likes: 0
I will be sure to double check that. I know it was tight after re-install and after an initial double check. My plan is to also start checking suction at every junction from the booster, back to the pump as well. I have some time to work on it tomorrow.
Postmaster
Joined: Dec 2011
Posts: 3,860
Likes: 7
The vacuum pump may well be the problem; as they get old, they suck less and less - takes longer and longer to build up pressure in the reservoir(metal can).
It doesn't take that much to turn that pully, so while the belt should be reasonably tight, it's not nearly as bad as the power steering pully.
It doesn't take that much to turn that pully, so while the belt should be reasonably tight, it's not nearly as bad as the power steering pully.
Junior User
Joined: Feb 2015
Posts: 77
Likes: 0
The vacuum pump may well be the problem; as they get old, they suck less and less - takes longer and longer to build up pressure in the reservoir(metal can).
It doesn't take that much to turn that pully, so while the belt should be reasonably tight, it's not nearly as bad as the power steering pully.
It doesn't take that much to turn that pully, so while the belt should be reasonably tight, it's not nearly as bad as the power steering pully.
I gave new/reman vacuum pumps a quick look online and they're over $100! So much for a "cheap" fix...
Elder User
Joined: Feb 2008
Posts: 867
Likes: 3
From: North Bend
Lost braking power
If it helps any... $100 is nothing compared to not quite stopping in time and effing up your truck or someone's family.