I have 2005 f150 Crewcab fx4 the other day i was doing 65 and there seemed to be a vibration in the truck. I couldn't put my finger on where it was coming from at first. I know that if you feel the steering wheel vibrate the problem is with your front-end. If you feel the vibration in your seat, it is the rear end.
Well, The vibration was there for 7 miles then it stopped. Its timing has no pattern that is consistent. Then yesterday it started and I was trying ID steering wheel or seat, but what I noticed was I could feel it in the steering wheel but, the steering wheel was not shaking at all. So, I determined the vibration isn't coming from front or rear tires, it seems to be more of a vibration coming through the frame. With this, I started checking the temp of my rims when I got home. You could have cooked an egg on either of the front rims. And it did seem as if there was some lag or as if the truck wasn't fully coasting freely. Like the brakes were slightly depressed.
I believe the front brake cylinders are coming apart or have deformed or age has caused them to fracture. Does this sound like a problem and answer that is right?

 

I just traded in a 04 FX4 but I did have problems like you are describing, My wheels got hot from the brake caliper hanging up. I read a post on another fourm that said it could be the brake lines (factory rubber one was prone to kinking) I replaced pretty much my entire front brake assembly. Lines with SS lines, and thought I should get new rotors because mine got HOT, well when taking the caliper off of the rotor I broke the pistons (my guess was they weakened from getting so hot). So I ended up doing lines, rotors, calipers and pads along with a fluid flush. Oh and make sure to really grease the sliders good with a good high temp grease! That fixed the hot brake/wheel problem.

The vibration you are talking about, I would be checking your ball joints if your Truck has over 100k on it. I had the same vibration in my truck, really hit or miss but never occured unless I was going 55+. Really bad shoulder wear on the inside of my front tires gave it away as well. I replaced the upper and lower ball joints along with the tierod ends for good measures because they where cheap and easy to do. My truck also had around 150K when this happened.

I want to say the new brakes cost around $150 after the core exchange and the ball joints where $65 for the lowers, $250 for the uppers (on the 04 you can just do the ball joints you have to do the whole upper control arm) and $50 for the tierod ends.

Whole process took about 2 hours a side. You will need a ball joint press and snap ring pliers along with your basic tools

 

You have sticky front calipers.

 

your rims were hot? or your calipers were hot?

 

If the rims were hot I bet the calipers were even hotter.

 

exactly. the calipers and rotors were probably much hotter, good thing he didnt touch those i guess