I just bought a 97 F-150with 50k miles on it. It's in super shape. No rust, paints in great shape, and runs excellent. The only problem is there's an annoying vibration when you drive down the road.

When I test drove it, I noticed it right off. Taking it back I mentioned it to the dealer. He said it was cause somebody who tried it previous had left the emergency brake on and he would fix it. Ok, sounded reasonable. I bought it and drove it most of the way home. I got almost to my house when I noticed a odor like burning wires. They DPW was paving the road so I didn't really think anything of the smell. I didn't think anything that is until the truck began to act like I was driving with the brake on... You'd hit the gas, the truck would move, but when you let off, it was just like you had your foot on the brake. I got home, called the tow truck, and had it towed back to the dealer not daring to drive it.

They fixed the problem and I picked it up a couple days later. However on the way home, same vibration as before. Feels like you're going over washboard on a dirt road. I called the dealer back up and they said to bring it back over. They replaced the front brakes, back brakes, emergency brake cable, replaced the gasket on the rear differential, and checked the drive shaft. I picked it up a couple days later.

Grrrrr... same problem!! So the only thing we could think of was maybe tires. Took it back, they replaced the front tires and inspected the rears. The problems seems greatly reduced now at times, however at others it's completely the same. Around 35-50mph seems to be the favorite speed, but it will do it at almost any speed. After 50 it's less noticeable, but then all the sudden it will start doing it. I thought for a little while turning at speed had something to do with it, but I can't be sure. I did notice now when you slow down now to around 5mph, you can feel what feels to me like brake pulsation like when you need new rotors, but they replaced them. (shoulder shrug)

We're at a loss and hoping somebody might have an idea. Thanks for your time.

 

Did they take the rear discs off and check the EmG brake hardware?
Seems your dealer has gone out of his way to fix the issue but not doing a very good job of testing and checking until some cause is found.
Your ahead with all the new parts through.
Reason I ask about the EMG brake system is that they come apart inside the rear discs and have no place to go but bind up from time to time while your driving.
Good luck.

 

Did they replace the brake hoses? Are the brakes still getting hot?

 

Is it simply a vibration or more of a bounce? Is it the whole truck or does it feel more prominent from the rear or front?

 

I think they did. I can ask for sure.

 

The whole truck vibrates; seat, dash, steering wheel, everything. The only thing I can equate it to is like driving on a washboardy road. I've really tried to feel where it's coming from and I honestly can't tell.

 

As Bluegrass 7 stated the rear park brake linings separate from the shoe and can hang up in the rotors drum. If they changed the rear rotors they should have noticed that. If they didn't remove the rotors???

4wd truck? Is it stuck in 4wd or one hub locked?

 

I would also look at the driveshaft, it would only take a couple of minutes. I had a pretty bad vibration before and it turned out my driveshaft had just a slight minor bend to it but when it's spinning it would rattle your teeth out.

 

I will be sure to ask. I know they said they did work back there. No, it's 2WD.

 

They said they checked it, but that's been in the back of my mind as well.

 

2 or 4wd? Anyone ever check the U-joints? If 4wd check the front drive shaft u-joints too.

 

Just an FYI, a 1997 has regular drum brakes in the rear.

If I had that truck, I would probably start by putting the rear axle up on jackstands, then let it idle in Drive, and carefully look/listen at drive shaft at both ends, sight down the side of each rear wheel to see if there is a wheel shimmy, etc. etc. a lot of looking and listening.

If it has an "open" differential, it is possible that only one rear wheel will rotate under engine power when up on stands, have to stop with brake and slowly let off of brake again and again to get the other or both rear wheels turning (there are other quicker ways, but for safety sake I'm not going to try to explain it in just a few words).

Safety First! ALWAYS know where your head, hands, elbows, knees and feet are when going under/close to any moving machinery that would just love to rip off/crush/mangle your body parts! Spinning tires just off of the ground are more dangerous than they look to one that is busy trying to find a problem.

 

Did you ever find the cause of the vibration? What was it?