Hey Fellas,

I am new to the forum but not F150's. I have spent the last seveeral days researching your site and others to try and fix my brake issues on my '00 F150 XLT 2wd w/106K. It has 4 wheel ABS.
PROBLEM:
The problem is after some brake work and a brake flush last summer my brake pedal has never been right. Been through 2 Mech's and alot of parts. 90% of the time the pedal is great. Then without warning it drops about 2 inches before it engages. It then returns to normal once released and reengaged. I cant reproduce it on a regular basis, but it doesnt happen in stopa nd go traffic. Never when cold, only after driving a while.

SEQUENCE OF EVENTS
I took my truck in to Mech #1 in July 09 for rear pads and rotors.. then all the problems started. Turns out I needed axle seals as well so I did those too. Guy said the fluid was really dirty so we did a flush too. Got the truck back and had a great pedal for about 10 miles then whoosh.. almost no brakes. Pumped it and they came right back soild and stayed solid for a while.. then did it again. No warning.. just whoosh. this continues to be the problem throughout. Mech #1 is a freind and didnt hose me around on the money at all and tried his best to fix it.. it went like this

Took it back, oh we need to bleed it agian
Not fixed took it back
Oh yer MC must be bad, we replaced it and bled it
Not fixed took it back
Oh it just needs bled again
Not fixed took it back
Hmmm bad MC we will replace it again and credit you
Not fixed took it back
Oh it just needs bled again
Not fixed took it back
Hmmm rarely happens but maybe we got 2 bad MC, bought one from a different supplier.. gotta be fixed now.
Not fixed took it back
Oh it just needs bled again
Not fixed took it back
Wait we found the problem Your ABS pump is bad we replaced it with a used one and now you are all good... (turns out the light in the dash was burnt out so I didnt even know I had ABS for the last 3 years I owned the truck lol)
Not fixed took it back, but I have ABS now..
Oh it just needs bled again
Not fixed had enough of Mech #1.

Took it to a Merlin brake shop I trusted and have used in the past and they screwed me.

Oh you need 2 front calipers, bleeder screws are all jacked up and rounded off we cant get them loose. Ok.. thats BS but the truck has 106K on it.. ok replace them and get the dang air outta the system.
Not fixed took it back
Oh it just needs bled again
Not fixed took it back
You have a bad MC, no I dont I have had 3 new ones problem is EXACTLY the same. Oh we looked at it the rod behind the MC was bent by the other guy, we straightened it out, now it fixed for sure.
Not fixed took it back
Oh it just needs bled again
Not fixed took it back
full system flush and check problem the same...um... take it to Ford we dunno.

After reading and reading and reading, I am thinking there is air in the lower portion of the ABS HCU that never has been properly bled out. Ford wants $150 to do the job but does anyone think I am missing someting here or had a similar issue? thanks for the help