I have had this truck about 13yrs & use it little cab & chassis dually dump, lt has had an unbearable front wheel hop to the point you need to come to a complete stop to get it to quit hopping, it looks to be the drivers side front tire bouncing off the ground :confused:
just a single add a leaf had ever been added to compensate for the heavy plow.
replaced almost everything in the front end including new tires, still has old rancho shocks on the front.
hop starts at like 20mph & by 30mph the glass may shake out of the cab so i stop. i get the shake through the steering wheel just as it starts as a warning all hell will break loose :(
everything appears tight in the front end, any thoughts would be apreciated, i am not new to my way around a 4x4 but i am open to any possible resolves.
Thanks in advance

check your king pins and bearings yet?

I have a 91 f-350 4x4 diesel and I am very familiar with this shake you are talking about.
after many hours of searching I found that my track bar bushings were worn,
but when I did the track bar I also changed the front shocks so I cant say with 100% honesty weather it was the bar or the shocks but one of them was the culprit:)

search for the term "Death Wobble"

I cannot rememebr if 1990 had kingpins or balljoints

Thanks for the replies, much appreciated

kingpin model axle, they seem tight, as does all the bars on the front, this is a 7.3 truck too.

maybe the shocks are bad :confused:

the u-joints replaced spindle needles & inner & outer wheel bearings been checked & greased

it certainly is a Death Wobble & i will do a search on it :(

google Death Wobble & alot is posted on the subject..

Steering Stabilizer. A tight steering stabilizer can mask problems with the steering, but if it's loose it may allow DW to occur in cases where it normally wouldn't have.

my truck does not have a stabilizer, is it needed & if so should i put a dual one on it?

main problems caused by death wobble are...

bad wheel bearing.
bad kingpins/balljoints
bad tire rods
bad steering box
cab mounts
shocks
steering stablizer
cupped tires

think thats the basics, my 78f150 does this, it did it before when i had the stock axles and ran coils in the front, now everything is replaced and i have leafs up front with all new kingpins. etc etc. only thing left is the steering box. i tossed a stronger steering stablizer on it to help me get by for a while

This sounds like a classic kingpin issue, aided by other worn out parts. Get a rebuild kit from one of the fine POR vendors, and then also check the track bar bushings.

Shocks and a stabilizer only mask the real problem. Hell I ran an F-350 for weeks with NO shocks, NO stab, and No track bar. Rode like a Caddy! Check those KP's.