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

 

just bumping back up hoping for an answer..

 

I'm suprised you let it go on that long. I would definitely take it to ford. No sense in wasting any more time and money on people who can't figure it out.

 

MAYBE THIS WILL HELP

 

Thanks for the help, I will look into the dump valve.. although for what its worth the truck has been better since the last power bleed. Pedal has only dropped once in the last week or so. So I am still thinkin its air. But if I read that right, its saying replace teh EHCU not the pump itself.. I can get the module rebuilt for $130 at module masters online. Althought I am a bit confused as to why the control module would affect the dump valve...eh I can fill a book with what I dont know I guess. Thaks guys keep the ideas coming

 

it's wierd how it's worded normally the hydralic part is refered to as the hcu, while the electronic part is refered to as the ecu, but in the diagram you see them working on the hcu which is where the dump valve is

 

Yes it is odd. The drive to work and back yesterday and today, no pedal drop. Only happend twice since the last power bleed. It has been better the last two times I have had it done, thats why I keep going back to the air in the lower part of the HCU.

After futher review of this diagram on the EHCU thing, I think they mean for me to replace the ENTIRE assembly if the dump valve is bad. Which is large coin conisdering the reprograming of the ECU too. I checked on the ECU common problems and other than running the ABS constantly when they fail there are no serious issues in the ECU that would affect my problem. So I am gonna hope its air.. lol Its the best its been in six months so I am kinda afraid to mess with it now.. but will prolly take it to Ford and have them use the scanner to bleed it.

Any further ideas appreciated

 

any update?

 

Not Really,

I have just been dealing with it. I had the brakes power bled at a Midas shop one last time and it helped, I still have the same problem but not nearly as bad. I am convinved its air in the ABS. Ford has a specific procedure but the service mangler said $130 and no gaurentees. So its not bad enough for me to worry about right niow. What I read was anything upstream of the ABS pump or the pump itself you need this specific cycling technique done. Good luck.

 

I have no idea if this will help but does your abs get used alot? If not I'm wondering if forcing it to work, gravel roads, water, etc. will get the fluid movement in the ehcu to dislodge any trapped air.

I know where I live my abs is functioning alot so the echu's fluid is circulated but there must be places where dry conditions are plenty and abs never gets a work out unless panic braking is used.

 

Another guy, right now has the same issue. It almost for sure is air in the lines. With ABS/air in the system, a dealer has to plug in their laptop and do a " service bleed". This cycles the ABS and allows the air to be bled off through the bleeder screws. Without this service bleed, you'll be on it until spring probably and it still won't be right. The ABS valves trap the air when trying to bleed the brakes with the vehicle parked.

Dave

 

Does it have to be a Ford Dealer? The shop I go to says they have the program to do this. Is the computer program that does the service bleed available to other repair shops?

 

I couldn't say for sure, kevhenn54, I've never had it done anywhere else. I'd think a full service repair shop would be able to do it. I almost never have any one else work on my vehicles. But in this case (without actually checking) I assumed it would cost too much for me to buy, and hardly ever use it. Now I'm curious. I'll look around.

Dave

 

Thanks, but sounds like you are 100% sure this MUST be done. I replaced the ABS unit over the weekend and bled the brakes and the brakes work but feel a little funny. I read the manual and realized I did not bleed the way the manual says. I am going to bleed again this week. Please let me know what you find out.

Kevin

 

kevhenn54

With the criteria discussed, yes, you'll likely need it done. Any faulty brakes after breeching the hydraulic system, and having ABS, can result in needing this.

No problems if you just changes pads, rotors, if the lines aren't removed. You should be able to try a couple of panic stops to activate the ABS (no cars around you). If the brakes get worse after wards, then you know

Dave