Weak Brakes - Please Help

[AngryBird]

Hey Guys,

I recently purchased a 2011 Expedition with about 15000 miles. The brakes are horrible, especially after it has been sitting over night. My wife was backing out of the driveway (which is slightly sloped towards the road). She realized a car was coming and pushed the brake pedal to the floor. The Expedition slowly rolled to a stop and almost hit the car. She told me about the issue so I drove the vehicle to test it for myself. Come to find out that the brakes are really weak in forward and in reverse(much worse in reverse). The pedal hits the stop and the tires don't lock up nor does the ABS kick in as you would expect. The pad thickness front and rear looks fine(1/4in of material left). Rotors seem like they are in good shape too(its only a year old). The braking does seem to get better as the expedition warms up. I have no idea what it could be but clearly something is very wrong. I have an appointment with the dealer on Friday, but I was hoping it might be an easy fix. Thanks!

AB

 

[GAINMOB]

upgrade from factory brakes to drill/slot brakes and ceramic pads for increased breaking power...have them test the master cylinder and brake booster/pump...could be faulty

 

[mindgame]

Did you change and flush the brake fluid to each caliper? I would try this first..

 

[splintrcel]

It sounds like u need to bleed your brakes. You can do it old school and push the pedal a bunch and have a friend let some fluid squirt out the bleeder screws until u get better pressure. Or the better way is to use a power bleeder. It's really simple and easy to use and is way faster. It creates a little vacuum pressure in a rubber hose that slips on the bleeder screw. Once u create that vacuum u open the bleeder screw a tad an fluid will start being sucked out. Continue pumping the power bleeder to maintain the vacuum and make sure or brake fluid reservoir doesn't deplete. Shut the bleeder screw when u see no air coming out. U want to keep the vacuum until u shut the bleeder screw so air doesn't re enter it brake lines. I don't think the kit is to expensive. I used one to completely swap my fluid when I rebuilt my calipers.

 

[FordandPolaris]

+1 on the fluid. If there is air in the system it would cause squishy brakes. The factory brakes should stop the truck at low speed no matter what, so I would check fluid, master cylinder and booster.

 

[AngryBird]

Ok thanks for the help. I have a Mity-vac so I'll try to bleed the brakes. Even if it is air in the lines, I'll take it in for warranty diagnosis of the master and booster. Something must be leaking air in for it to get air in the lines with only 15,000 miles on it.

 

[splintrcel]

by vacuum i didn't mean like a shop vac. I was referring to pressure as in there is suction created. A vacuum prob isnt what you need. A power bleeder is just a hand pumped cylinder with little hoses on it. Its kinda a deceiving name. I can link one if you want. The goal of a power bleeder is to create a negative 5 to 15 psi to pull fluid and air out of the lines.

 

[AngryBird]

So I took the Expedition in to the local Ford dealer today. They said it is just taking a little time to build up vacuum in the brake booster. If you start it up and rev the engine up to 2000 rpm or so it builds up vacuum and the brakes work just fine. I don't know. Seems kinda gay. I don't have to wait for vacuum to build in any of my other cars for the brakes to work right. At least I have a temp fix (revving the engine once) so my wife doesn't run over neighborhood kids when backing out of the driveway.

 

[splintrcel]

Bad brake booster?

 

[AngryBird]

They claim it tested fine. They are putting in an engineering request with the problem. I'll let you guys know what they tell me.