Nearly soiled my drawers the other day.

1993 F-150. 300 I-6, E4OD, nothing special. XL. Been a great truck in most respects. No complaints.

I have experianced a severe vibration problem 3 maybe 4 times. Most recently I drove home from work, about 19 miles. Stopped to pick up some supplies (beer) and started driving back home, about 3 miles. Halfway home I noticed all the junk in my glovebox was rattling, and it got worse from there. A hundred yards down the road the the vibration turned violent. I could see my dashboard shaking and the noise was unbelievable. I gently braked and pulled off the side of the road. Vibration continued until I was down to about 15 MPH or less. Got out, looked for something bad like a bent driveshaft, loose wheel, chunk of mud stuck to a wheel, anything. Nada. Went home, no vibration. 10 minutes later I went out again to give the underside a good inspection, or at least as good as I could in the snow and ice. Nuttin. Test drove it for about 2 miles. Nuttin. Next day, drove it to work and home, about 19 miles one way. Again, nothing.

This happened once last summer or early fall. At that time I chalked it up to a tire issue or flat spot or something since it had sat for nearly a month unused. I ride a motorcycle whenever ice isn't on the road. That time I had to use the truck to get 2 gas cans filled up for lawn equipment.

No recent changes with wheels, tires, shocks, anything. In fact the only thing I've done lately is change the oil and vacuumed out the winter dirt & crud from the cab.

Ideas??

Thanks..

Pat

 

Did you hit a bump right as the vibration started? How old are your shocks? May just be old shocks not being able to dampen an impact and the springs causing an amplified affect on the suspension. A steering stabilizer and NEW SHOCKS will probably keep everything stiff so that it never happens again.

 

Nope, no bump or anything unusual. Rear shocks prolly 3 years old. Fronts 5 or 6. Don't remember exactly. I've never in my 30+ years of driving and vehicle owning experiance had a shock go bad judging by a bounce test. I just replace them when I'm in the mood or as in the rear shocks when the outer shield rusts away.

Only other thing I could add which is probably of no importance is that the vibration build up is gradual. Meaning it happened over a 3 to 5 second period of time. Not one of those "all of a sudden" things.

Co-workers, pro mechanics, and others have been baffled by this and may be questioning my sanity by now.

 

Do a thorough inspection of your front end:

ball joints
tie rods
wheel bearings(are these loose?)
etc.
aligment- you prob did already.

Sounds like death wobble/speed wobble to me, very hard to track down sometimes and is usually an intermitment problem. I've just gotten into Fords myself so I haven't really anaylized the front end on these trucks but a big culprit for the problem you speak of in other brands is the King Pins and King Pin bearings.

 

Thanks! You jogged an old memory. I had a 81 that had king pins and they wore out. Symptoms similar to what I'm experiancing now. This beast has ball joins, maybe they're worn out. I'll check those if it ever warms up.

BTW, you touched a nerve. Much discussion about Harley FLH's and high speed wobble. Haven't experianced it myself but it too is described as a "death wobble" since one more often than not looses control and could end up having real bad day. LOL!

Thanks again.

pat