Kymasabe

92 F150 brakes pulsated like mad, one caliper was sticking, one brake hose was starting to disintegrate. So, today I replaced rotors, pads, inner and outer wheel bearings, seals, calipers, hardware, and brake lines. I bled the brakes with a Motive pressure bleeder, went thru a quart and a half of fluid, bled both side twice and.....pedal goes right to the floor. I'm thinking maybe the master cylinder failed, but honestly, I have no idea how to check it or what to do next.
So, I put it in neutral, pushed it out the garage door, and let it roll down the driveway and across the street into an empty field. Was gonna shoot it, but I guess I'll just have it towed on Monday instead....unless someone has some insight into what could be wrong.

Chris_1

iTrader: (1)

If you have fluid and you figure you got the air out, you should have a pedal.
Either the fluid is leaking onto the ground when you step on the brake, or the master isn't pushing fluid into the lines.
Can't think of anything else it could possibly be.
You bled the back brakes too ?

Kymasabe

I'm pretty sure I got all the air out of the front lines, filled my catch bottle 4 times. I've been looking on the garage floor, nothing is leaking.
No, didn't bleed the back brakes. They're new, were bled two weeks ago, I figure replacing the front brake lines isn't going to get air into the rear brake lines so...didn't rebleed the rear brakes.

whatpavment?

Are your calipers on the right sides? I had the same issue because mine were upside down.

88xlt

That's exactly what I was going to say. I read of a few instances of this happening on these Ford pickup trucks. The bleeder valves should be toward the top.

Kymasabe

Yup, on correctly, bleeders on top, just like the ones I took off.
I'm still thinking it's a bad master cylinder, but that'd be so weird/coincidental, unless I blew it apart when I pressed the old caliper pistons back in when taking the old calipers off.

Kymasabe

Well, discovered the problem was the master cylinder. Removed brake line after brake line trying to find a restriction until I got all the way up to the master cylinder and found I had almost no fluid coming out of it. When I bled the brakes, I used a Motive pressure bleeder with a Ford adapter on the master cylinder. I used a turkey baster to get as much fluid out of the master as I could and refilled with fresh fluid. Turns out, there was 20+ years of crud and muck and nastiness left in the bottom of the master cylinder, and the pressure bleeder managed to ram it all down to the bottom and clogged it up. So, new master cylinder, flushed the brake lines and re-bled everything and....we're up and running again.
I've said it before and I'll say it again...LEARN FROM MY MISTAKES !!