My passenger front caliper siezed on my '05 at 75K, smelled like a permanent marker and was smoking. It was shaking on the highway as well. Shouldn't be any hotter than the others, if it is, it's hanging up and needs to be replaced.

 

Yeah. I'm assuming the caliper is seized, so I will most likely be replacing that as well once I get in there and check things out.

Question - should calipers be replaced in pairs, or can I get away with replacing just the one side?

 

Worn, cupped tires can cause vibrations at certain highway speeds, most likely felt all the time. Wheel balancing can cause the same type of feeling, should go ahead and have them balanced just to make sure. The brake pedal itself will pulsate if the front rotors are warped. will also feel shaking in the sterring wheel and cab due to brakes. U-joints will cause harsh cab vibrations mostly while accelerating but can be felt all the time. Lower ball joints can cause a very slight vibration when loose, but id look elsewhere first.

Yes you can replace just one caliper at a time. It sounds to me like it seized thats what your vibrations are and your rotor being super hot. should replace that caliper, possibly the line, and the rotors (replace rotors in pairs 99% of time) and pads if there under 40% material remaining. hope this info helps ya!
heres a helpful tip on how to make sure its your caliper not releasing correctly. (you'll need an infared therm; $20 autozone) drive it a few miles give it a few good panic stops and park the truck. get out and quickly check the temp of both front rotors from just outside the front wheel. The locked up caliper side will be about 75-150 degrees hotter and possibly red looking and pad glue oozing out the sides.

 

I don't know of any reason to replace in pairs. I replaced my rear driverside due to seeping fluid. Then around a year later my front passenger due to seizing. I haven't had any issues, though I did replace brake pads and rotors in axle pairs.

 

usually its wheels being balanced. mine did the same thing, shaking would come and go, have a tire shop spin them with the wheel weights on and the machiene will tell you if it needs weight. mine shook pretty good, i had them spun with the weights still on it, straight off the truck, and one side needed 1.5 ozs and the other needed 2.5 IIRC. fronts is the steering wheel shaking, rear tires is the seat or your butt shaking.

 

Turned out that the front drivers side caliper was indeed faulty. One of the pistons was crumbling (as has been discussed here many times), so I'm guessing little pieces breaking off were causing the occasional vibration issues I was seeing.

$200 for two new rotors, a set of Wagner TQ's, and a new caliper. Not too shabby.

 

I had the vibration too, and it was lower ball joints around 80,000mi. I wound up taking it to Sears to do the work because I was busy and had already bought the ball joints. Sears would not put on the ball joints I bought because of "Liability reasons"....I think it was for parts markup reasons.

 

if the vibration is during braking, id look at the rotors for warpage first

 

I had a shake too. Roadforce balance revealed a bad brand new Michelin, left and a slightly bent rim, right side. A new tire up front and moving the rim to the rear took my truck to silky smooth.

 

FYI, if anyone needs ball joints cheap - I have some high quality MOOG replacements for sale on ebay that I mentioned I got stuck with: Only $50 Sorry for the plug

Update - Sold the joints