I have an 89 2wd, 4cyl 5-spd truck, and i've been chasing a vibration in the front end. Tried 3 sets of tires on 2 sets of rims, multiple re-balancing, even replaced calipers and hoses, and turned rotors in case something was hanging up. Tie rod ends are tight. Wheel bearings are fine. I'm out of ideas...

 

All speeds? Same when going straight as turning?

Is it possible your actual wheel hub is bent? It doesn't take much if the truck has ever slid into a curb sideways or something to tweak it.

Otherwise my only other thought is possibly bad steering rack or steering gear. Though I've never experienced failure of those components, I'd imagine the shaking would probably get worse when turning, and perhaps worse when turning one direction vs the other.

 

Starts at about 45mph and stays pretty constant from there. Sometimes it's worse than others, occasionally you barely notice it. The rotors were turned, so they should be true. I also replaced the u-joints in case it was a driveline vibration. I also had the tires balanced at a different shop in case the first guy's machine was out of calibration. I can't find any play in the column or rack and pinion either. I've thought I found the problem several times, just to take it back out on the road and have no change. Stumped...

 

Are you sure its the front end? May put it on jack stands and see if its coming from the rear......

 

if the vibration is present when your NOT braking; its not brake related.

where does the vibration transfer to...the steering wheel or the body of the vehicle?

 

The vibration is in both the steering wheel and the body, it kinda goes wiggle-wiggle-wiggle in the wheel then wiggle-wiggle-wiggle in the seat, back and forth. The reason i went into the brakes is because one rotor was about 50 degrees hotter than the other after 15 minutes of driving. Not to mention, the hoses were looking pretty crappy. I didn't really expect it to get rid of the vibration, but it needed done anyway. This truck was part of an inheritance, and the guy's kids trashed the truck somewhat when they found out they weren't getting what they wanted from the will. Threw a sledgehammer thru the windshield, and took the keys. The guy who inherited it had to break the steering lock and ignition switch to get it moved. At first I figured either the tires were junk from sitting for a couple years, or the stock steelies were bent, but I've replaced both with no improvement. Someone also had a toggle switch rigged up for the fuel pump/coil, which i am pretty sure is a bad ECM. The ASD relay is not getting a signal. I have it rigged up to run off of keyed power at the diagnostic connector right now, until I can find a computer to try in it. Checked all grounds etc, nothing wrong in the harness.

 

Check the two large bolts that hold the rack/pinion to the cross member frame. They have a welded nut that holds the rack in place. The nuts are inside the cross member...you can see them as there is an access hole behind each one. They are notorious for breaking off the cross member. Also check the bushings that these bolts go through that hold the rack. They can wear too. It sounds like it's in your steering. Don't know if you've changed your inner and outer tie-rods, but that'd be next on the list.