Hi every one, I have a 77 Ford F150. It is a Camper Special with the 351M and 4spd trans. I have had the tires rotated and balanced 2 times now and I still have a vibration from the front at around 65mph. It gets worse the faster I go. Never getting over 80 though, there is no need to go faster then that lol.
Anyways it will shake so bad I see the front of the truck, mostly the drivers side shake up and down. And if I turn the steering wheel just a little as if to change lanes at that speed it gets worse. I don't know what to look for to fix or replace. I have grabbed, touched, greased and regreased everything I could. I don't know how old the shocks are but they look new.

I have jacked the fron up and tried to move the tires and wheels to check for a bad wheel bearing and it is all tight. I am at a loss and need help/advice. Thanks in advance for everyone's help. Oh and by the way the tires are Goodyear Wranglers, 235/75-15 on stock steel rims.
Greg

 

How's the alignment? Have you checked the toe? You should have between 1/16" and 1/8" toe in.

 

The alignment has been checked and is good.

 

spun balanced or bubble balanced? Spin bal. would find a broken belt. Might have to try a spin -wheel on vehicle -balance.

 

Have you checked to see if the tie rod ends and king pins are tight? When I had my 18 wheeler, we had to get a tire now and then trued. They would have you drive the vehicle until the tires got warm, bring it in, they would jack it up and put the tires on a tire lathe. It was surprising how much they could be out of round. Get the tires warm, jack up the front end and rotate the tires by hand and you will see if they're round. If you have after market wheels with spacers between the wheel and hub, the weight distribution on the bearings will be off causing excessive bearing wear.

 

Is it 2 wheel drive?

 

It is a two wheel drive. At this point I can say that it doesn't happen all the time. When I first bought the truck it had sat for a while. The front brakes are disk and when the front is up and I rotate the tires it seems as though the brakes drag when they are warm. After it cools off they rotate more freely. Could I have a warped rotor?

 

Make sure the calipers are lubed and free. Possible Master cylinder to booster rod adjustment needed.

 

Sure sounds like the calipers are sticking,

 

I had a '70 Chevrolet CST-10 once back in the '70s. It came to me in a trade, was a nice truck, BB / T-400 / loaded / etc.

It had some 15x9 really deep dish aluminum wheels .... and stretched on the front wheels were some G70-15 tires, it had 11.00-15 deep lugged rear tires. Every now and then, and often in the same circumstances, it would start shaking and the steering wheel would shake back and forth and it would get worse and the only way to stop it was slow way down and it would stop and I could speed up and it'ld be OK.

Ball joints and tie rod ends were tight, nothing was loose. Truck had 50-60K on it. I too even tried new tires with a set of "Road Huggers" (RWL, G70-15 and L60-15), no change. Was unnerving, but only seemed to start if you got the speedo over 60 so I didn't.

Then I replaced the wheels. The truck had had sidepipes from a prior owner and the rear aluminum sheels were badly pitted so I bought new 15x8 white spoked wagon wheels. They were an inch narrower and they had less back space, but looked great on the still new RWL tires on the black truck and the frt tires especially fit better.

Suddenly, with the change in wheels, the problem was gone. Never had another steering wheel shake after that. It handled better, drove better, wandered less. I guess something about the aluminum wheels just had too much dish and too wide which moved the tire out and the truck just didn't like them.

And back about 2003 one day, my '77 F150 4x4 started that just out of the blue going down Rt 11, no warning .... belt speration and big lump popped up on LF tire. Was an old set, I pitched two and still have two as spares.

 

I wonder if it could be the rubber bushings where the radius rod connects to the frame bracket? I have seen them worn badly before.