Mechanics

F150 SPONGY BRAKE PEDAL

1993 Ford F-150 • 6 cylinder 2WD Automatic • 94,000 miles

Front brakes growling for several days so I replaced everything on my F150 brakes: front brakes - wheel cyl, calipers, rotors, pads, inner / outer bearings and dust seal; and rear brakes - shoes & drums turned. Fresh fluid - 3 qts - and flushed the system twice. Checked for any leaks - none; however, spongy brake pedal persists.

When I'm done bleeding - 2 person method: one in vehicle and one under truck - the pedal feels strong; however, when I start the truck the pedal goes nearly to the floor. It will stop but it is uncomfortably soft. I've only driven around my neighborhood at 20-25 mph max. I don't trust it to get on the highway.

This model does have ABS which seems to work fine.

Suggestions?
dleiland
Avatar
Dleiland
April 19, 2011.



If you ran the master cylinder dry, there is likely air in the ABS hydraulic controller. You may need a scanner to activate the valves to get the air out. In the future, to prevent the master cylinder from running empty, place a stick from the seat to the brake pedal to hold the pedal down about 2". The lip seals will hold the fluid from running down until you're ready to bleed.

Also, when you use a helper to bleed the brakes, tell them to never push the pedal more than half way to the floor. Doing so will run the lip seals over the crud and corrosion that builds up where the seals don't normally travel. If the seals get ripped, you'll have a pedal that might pump up at times, but if you hold steady pressure on the pedal, or modulate that pressure slightly, the pedal will suddenly sink to the floor. It doesn't sound like that's what happened to you, but keep that in mind for the future.

Caradiodoc
Apr 19, 2011.
Did you adjust your rear brake shoes (brake spoon) Till the shoes just start scraping the drums (not too tight now!)While spinning the tire by hand?

The ole self adjusters really do not do this initially, when you slap the brakes on, they just take up slack after they are adjusted, and the shoes wear.

Ask us questions (Doc and I) we love helping! We will assist you as far as you want to go! (Only the unasked question is the dumb one!) Then you can drive to Wisconsin, Doc will see how well you did!

The Medic

Tiny
CJ MEDEVAC
Apr 19, 2011.