bought an 89 f-150 4X4 yesterday, with a 300 inline six. test drove it everything was fine (for a 20 yr old truck). drove it to work and home. The closer i got to home, everytime i'd put on the brakes, the whole truck would start to shimmy and shake, eventually it became more of a bounce. I thought it could be the rotors, possibly a caliper going out, but nothing i've ever experienced seemed to really explain how or why this would happen. Also, i think it's noteworthy to mention that the truck would still "bounce" (and it was no small bounce, very exaggerated) even after i let off the brake and started to speed up again. Then it would stop. Any help would be greatly appreciated. If i need to provide any more information let me know. Thanks in advance guys.

 

don't know if it's relevant but i thought I'd add that it has 110,000 miles on it

 

Rotors and/or drums are warped(vibration with brakes on)

AND

Shocks are toast(continues to bounce after the brakes are released).

 

I have the same problem minus the bounce and it has ruined a tire as result. Rotors sound about right but what about tie rod ends? Wheel bearings? I just don't know and need help along with btorear.

 

The brakes are the cause if the vibration only happen when they're applied. Steering and suspension parts can be inspected for play and slop by jacking up the fromnt end, everything should be tight, do up/down movement in the ball joints or bearings, wheel should spin without noise, and should be very little free play in the steering linkage.

 

By saying the Brakes are the problem, do you mean pads? Calipers? Rotors? This weekend I am getting this in the air to look at the front end anything specific I could look for in steering?

Thanks..

 

great info,i really appreciate it. any other possibilities just in case?

 

That would be warped rotors, this can be seen by spinning the rotor with the wheel removed, a straight rotor will be the same distance from both pads all the way around while a warped rotor will touch at some points and not at others. Sometimes there's enough metal to machine this out but not if they're warn heavily already, a shop that does brake work will be able to tell you.

 

Mud in the rims? Maybe check and see if a wheel weight came off.

Simple things but they can cause problems like your describing, although that would really be the easy way out if it was either of those!

 

rotors are cheap, just buy new ones. Another way to test the shocks is to push down on your truck so as to rock it up and down. When you let off it shouldnt keep going

 

Do you feel it in the steering wheel or the seat ????? Steering wheel front , seat rear..

 

I have the same problem...gets pretty violent when it happens. I know this doesn't sound right, but I feel it from the rear end. I was told by my wise(old) mechanic neighbor that it probably has something to do with a brake line sticking. Which might make sense since I rarely use the e-brake and this only happens after I would use it...so pretty much I don't use the emergency brake and it doesn't happen... but if you have an auto, then you probably don't use the e-brake, in which cause you can disregard all my gibberish.

 

Hmmm....mine got pretty violent too. I gave it a once over last night, though i didn't have much time. I found that one of the pins that holds the caliper on, on the drivers side was just almost completely out, I'm sure that was having some effect. I also noticed that the u joint on the rear of the driveshaft (going into the rear end) needed replacing, wiggled too much (almost 1/8 of an inch). Think either of these or maybe a combination of both was causing my problems? Again, any help greatly appreciated.

 

also, i noticed that the drivers side brake pads weren't very worn, but the passenger side pads were very worn. Jnust thought I'd add that in case it's relevant. Anyone that can advise is much appreciated.