I have searched high and low to see if I can find the issues my truck has, but nothing seems to fit. Here's the details:

When I first got the truck I replaced the passenger side front wheel bearing because I was feeling vibrations in the wheel when I turned, however the OEM Ford hub was smooth as silk when removed. Hmm. But I erred on the side of caution and replaced it anyway. Fast forward.

For two months I noticed my driver's side front wheel developing a lot of brake dust in comparison to the passenger side. I also noticed that in braking conditions the brake on the that side had the signature overheating smell. But the truck stopped fine, there was no pull to the left or right, no ABS lights, naughta.

Recently after driving out after work one day I hear a loud pop and shortly after on my way home, the brake pedal started creeping. First thought is the master cylinder. Yay. As a precaution I also removed the front calipers to inspect the pads. This is where it starts to get interesting. The driver's side pads where worn down almost 5mm more than the passenger side, also the passenger side pads where wearing unevenly, like this "/ /". Uh oh, caliper slide pin right? I checked, the pins were not stuck and were well greased. WTF? INothing seemed wrong with the caliper, the pistons and seals were in good condition, so opted to just replace the front pads (I did make sure the pad with the ***** was placed in the back position). Next up, I bench bleed and install a new master following the proper brake bleeding procedure, RR, LR, RF, LF. As I was bleeding the system I notice that the pedal was very hard to push with the caliper bleeder open, I wound up having to turn the truck on to get the booster to help me bleed the brakes.

I then took it for a test drive and the truck felt so much better, like it had shed 500lbs of weight. Unfortunately the driver's side brake started heating up again under normal braking conditions. I suspected the passenger caliper was not doing its job, maybe it had a stuck piston? So I change it out. During the second bleeding process the master cylinder went dry when I had to step away for a bit and forgot to close the bleed screw. "F*ck!". I was having issues with the bleed screw not sealing and giving me false positive bubbles. Teflon tape to the rescue and I re-bled all the brakes multiple times, no air appeared but the pedal was still very hard to depress with truck off and the bleeders open. (I have done MANY brake bleeds and this is the first time that has ever happened)

However the 500lbs was back and the brake pedal was acting funny. Sometimes it felt normal and randomly the pedal travel would increase. Also when I backed up, the pedal was perfectly normal, the weird pedal travel only occurred going forward. This has been going on for a while. I thought it might be a trapped air bubble in the ABS system and that it might work its way out, but the way the truck feels, I think there is more to this.

Again, no brake light, no ABS light, no flashing traction control light. (I do know they work since the ABS was triggered frequently during the winter storm here in Texas)

If anybody has any ideas I would greatly appreciate it. My friends who deals with Fords exclusively thinks its the HCU, but I don't want to drop a lot of money until I am pretty sure its the problem.

 

Hmm,

136 views, 3 days later, no answers, no questions, no ideas?
I must have you really stumped. Okay... I'll see if I can find somewhere else that may have a solution.

 

so you replaced the passenger front caliper? My thought is the driver side is dragging/not retracting properly.

if it were my truck I would be a little guilty of hitting with the parts grenade. I'd go ahead and replace the driver front caliper, probably go ahead and replace/upgrade the first section of line from the caliper (Ive seen lines fail where it wasn't obvious for the outside but they were restricting flow). Braided lines aren't too expensive and a decent upgrade.

Do these trucks have ABS blocks like the older stuff? I know on my 03 mustang if you let air get into that ABS block it was a nightmare to get it to bleed, the easiest answer was taking it to a shop with a proper ABS diagnostic computer as there is a test/program they can run that cycles the ABS in order bleed out that part of the system.

Lastly wasnt there some kind of recall on the booster? Might be worth looking into what trucks it effected by it and what the issue was, maybe theres also something going on with the booster.

 

It could be the rubber hoses going into the caliper. Story is, they can come apart on the inside and create a flap that won't let the pressure release. I recently replaced all 4 of mine as preventative maintenance. They're fairly cheap.

 

Sounds like the drivers side caliper is the one that's dragging being that your pads were 5mm thinner than the passenger side. Have you double checked to be sure that the rubber brake hoses are not twisted? I've seen this happen a lot and it always causes odd problems.

I think since the system was bled dry you need to remove the master cylinder and bench bleed it again.

 

driver side front always wears a little more than other being closest to the master cylinder.

 

My 2013 F150 is in the shop for a brake problem. The driver side pin slider for the caliper is frozen. Won't allow the caliper to back off when the brake pedal is released. This causes the rotor to overheat and warp which causes the vibration. The vibration goes away when the rotor cools off. Had to the same problem on my 2003 Ford Ranger. Wouldn't be too surprised if they find the upper and lower ball joints need replaced also.

 

I had that happen on a passenger car (1971 Plymouth) years ago. Exact same root cause.

 

I suggest a reputable mechanic if a free Internet forum isn’t giving you what you’re looking for.

 

Truthfully the Hard push with the truck off is normal for these (My Mustang did the same thing when I replaced my Calipers to Brembo's), the booster is good for about 2-4 pushes and then won't go. The other would be to replace the front brake lines, either swollen and closed up or the flap from it coming apart on the inside as someone else has mentioned. Sounds like the right side was in backwards the first time if the pads were wearing like this //.