06 v-8 soft brakes

[ExplorerVa]

Recently noticerd that the brake pedal gets really soft once in a while. So far it has only happened at very low sppeds, like backing out of the driveway. Also happens going forward. Vehicle has just over 50k miles, AWD option. Took it to the dealer for a checkup and they could not duplicate the problem thus pronouncing it "no problem".

Happened again this morning in the parking garage at work. After driving 30 minutes, pulled into the garage at slow speed, tried to stop to back into the space, pedal went most of the way to the floor and it felt like it wasn't going to stop. Lifted off the pedal, pressed again, and it was normal. this has happened to other drivers, always slow speed.

 

[donstevens]

It may be a master cylinder going bad. But before you have that replaced try having the system flushed with new fluid.

My recently acquired 06 with 70000 miles had a soft pedal which bugged me. It would not go all the way to the floor but it would keep going (and creaking) another 1/2 inch to an inch even when stopped. I looked at the fluid the other day and iw as darker than Starbuck coffee. it had to be original. I just had it flushed today and the extra travel and creaking issue is solved. Still looks a little dirty though so I am going to do it again until it is clear.

Don

 

[waskly]

Recently noticerd that the brake pedal gets really soft once in a while. So far it has only happened at very low sppeds, like backing out of the driveway. Also happens going forward. Vehicle has just over 50k miles, AWD option. Took it to the dealer for a checkup and they could not duplicate the problem thus pronouncing it "no problem".

Happened again this morning in the parking garage at work. After driving 30 minutes, pulled into the garage at slow speed, tried to stop to back into the space, pedal went most of the way to the floor and it felt like it wasn't going to stop. Lifted off the pedal, pressed again, and it was normal. this has happened to other drivers, always slow speed.

i got a feeling abs is going out. i would def scan abs.

 

[thebrakeman]

I've had this happen with clutch master cylinders, and (at work) drum brake wheel cylinders. What you are describing sounds like the master cylinder needs to be rebuilt (or replaced, depending on what ends up being cheapest).

When you press the brake padal (or hydraulic clutch) the fluid forces the seals outward against the cylinder bores. This allows pressure to build, and the pistons slide. But as the seals wear over time, low-pressure applies may not force the seals out quick enough, and some fluid can leak past the seal. If the secondary channel is OK, you will feel this as a "soft pedal" and/or increased onset of braking. If both channels experience this at the same time, the pedal will quickly go to the floor, and you'll need to change your shorts! Typically, a hard apply will shock the system, and provide a good seal. Or, like you found, releasing and quickly applying (in a panic!!) will seal things.

Rest assured, this will only get worse. Have this looked at, or rebuild it yourself.

 

[vipersinu2]

Brake pedal slowly going down about 1/2 inch after stopped

2007 mountaineer 4.6, awd, 93,000 with traction control. My brake pedal slowly going down about 1/2 inch after truck is stopped. The fluid was very dark. I just flushed system, I ran half gallon through system complete clean. But problem still there, I noticed auto part stores sell a master cylinder without traction control. Does anyone have a tip on where to purchase a master cylinder with traction control or rebuild kit, and installation tips?

 

[swetrid]

Ford has Tsb 09-01-06 for brake pedal feel and firmness.

 

[cwescapexlt4x4]

Also finding Service Bulletin Number : 08-2-8 safercar.gov ... wonder what the mileage limitation is on this? I am at 86k