scarry wheel hop

[franshisca]

Thanks for the uploading

 

[79jasper]

Nothing I can see by the pics.
You say you did check kingpins?

 

[franshisca]

No, is there a way to check king oins with out turning the steering or... whats the easiest way to check them? This is hard stuff.

 

[fordf350man]

im not to sure on that model gm truck but if it came factory with a steering dampner then it has a purpose in that factory set up, a dampner is not a bandaid, when you start running larger tires they do become necessary to stop wheel wobble, some dont need it correct but that is a rare case, there are factory vehicles out there with solid front axles with factory dampners, so if thats bad it can cause wheel wobble

GUYS....

STEERING DAMPENERS DO NOT cure death wobble they only MASK the original cause of it. Sometimes enough to make appear gone!

DO NOT FIX steering death wobbles with a dampener, they are only for sudden bumps like, hitting a pot hole and needing to help dampen that impact to the rest of the steering gear!

One thing I've not seen is checking the CASTER angle, of the diff. If the truck is lifted or sagged out, or the housing tweaked, caster angle can have a huge impact on how a solid axle or any axle for that matter reacts or works.

Please guys stop with band aid suggestions like dampeners.

JM2CW

Al

 

[towcat]

i beleive this might be a desiel forum but i am having the same problem on my truck a 1990 GMC Sierra 3500 7.4 liter 1 ton four wheel drive (gas).
And i get this violent crazy hopping and shaking in the front on when i hit about 25 to 30 mph while driving. I have to hold the steering wheel tight to keep it from going all over the place. And i have to completely stop to make it go away. ITs driving my crazy.
In front only. i have put new shocks, rotors, brake, changed the steering tie rods, the center drag link tie rods, the steering damper is still good, (bought a new to be safe but havnt installed it) put new tires. Nothing changed My truck has king pins and cant really find what the symptoms are to see iif their bad or not. Also with the truck on in park position. i turn the steering back and forth but could hear a noise very hard to pin point, i know it only comes when i pmove the steering wheel back and forth. need help.
this is the most exspensive process of elimination

i just looked at your pics. nothing seemed unusual. one of the "free" diagnostic things you can do is take the inner dual off each side and move it to the front. run the truck on the same roads you have having the shaking issues and see if it is still present. if it goes away, you have tire issues. mainly the belt is separating internally. when you get replacement tires, don't go cheap. buy the most rugged tire money can buy. Why? A CCdually 4x4 front end is prolly one of the heaviest front axle weights god has ever put on the road and cheap tires are no savings.

 

[LCAM-01XA]

BTW, I love your truck.

Aye, nice truck you got there Franshisca, darn near bomb proof setup too if it has the TH400 auto trans or the SM465 manual.

The rubber piece bolted to your frame rail right above the axle is the bump stop - basically if you hit a hole or bump too hard the springs may compress enough to where the axle hits the frame, which is an excellent recipe for bent axle tubes. The rubber is there to absorb that impact and prevent damaging metal on metal contact. The missing one on the driver side can be easily replaced, Energy Suspension makes nice polyurethane ones in variety of shapes and sizes - I got a universal set at one of the big chain stores for like $15 for the pair, they are beehive-shaped and 2-1/8" tall when installed and use a 3/8" stud to attach to the frame - see how tall your remaining factory bump stop is, and then get something of the same height or slightly taller. Many people dislike having those as they tend to limit suspension flex while offroading, but since yours have marks of contact with the axle I'd say you really wanna have a matching pair there.

Kingpins check: reinstall the wheel, lower axle till wheel almost touches the ground, stick a long prybar under wheel and rest its tip on the pavement pretty much under the kingpin, and lift on the handle - if you feel the wheel move then either your wheel bearings are loose or your kingpins are bad. If you get a helper to lift on the prybar for you then you can wrap your hand around the kingpin resting it on the axle tube and if the kingpin is indeed loose you will feel it directly. Do this with both upper and lower kingpins, personally I always do both visual check and by feel, ain't missed a single one yet like that.

The steering damper on this GM truck is factory equipment, you can tell by the hole and stud for it the center link in one of the pics. Still, it is not there to prevent death wobble, the forces that cause death wobble are usually quite a bit more violent than the damper can, well, dampen. It does make the steering more stable on rough roads, which is great, but that's about the extent of its capabilities. If you have a new damper obviously run it, but don't expect it to be the magical solution to the problem... Then again, it just might work, so definitely give it a shot.

Also yes, do replace the bushings for the sway bar - again Energy Suspension makes replacement ones out of polyurethane, actually they make polyurethane replacement bushings for the springs and shackles too. My D60 has all poly bushings, same with the trac bar (pretty sure your truck don't have that one tho), truck handles like a dream and corners like it's on rails, I can't say enough good things about the poly bushings really.

Frame around the steering box, yes, it is the truck's frame rail we're talking about. You already found your steering box loose, so now inspect the frame rail it's bolted to very carefully for cracks. Even if you don't find any cracks it would be a wise decision to buy and install a brace purposely designed to reinforce the steering box mounting area and prevent cracks.

 

[rlb245]

So those are king pins? Not ball joints? I'm a little confused here.

 

[LCAM-01XA]

Yes, those are kingpins, all GM D60 fronts ran kingpins, Ford D60s from the same vintage were also kingpins. In '92 GM dropped the leaf-sprung D60 monobeam and switch to torsion bars IFS for the 1-ton trucks, Ford kept the D60 and leafs but went from kingpins to balljoints in the same year.

What are you working with anyways, 2wd or 4x4? Cause like I said a 2wd Ford has no idler arm at all, and pitman arm is just a chunk of cast steel with no parts to wear out, so if someone replaced those for you I'd say they were not very honest with you.

 

[ksingltn]

Franshisca, I can guarantee that your truck does NOT have king pins. It has ball joints.

Check your control arm bushings. And where the control arm bolts to the frame.
Also sway bar and end link bushings.

he does have king pins, chevy one tons didn't go IFS till 92. He has a passenger drop low pinion KP Dana 60 under his truck, if its factory.

EDIT: I completely missed the last page where this was resolved.

 

[rlb245]

When I first got the truck the rancher said that the steering linkage had been modified a little. I didn't pay much attention to it until the death wobble thing showed it's self. I didn't replace the Idler arm, I removed it! It was connected to the frame and the drag link. When i ordered the parts for the front end the part's guy said that year did not have a idler arm so I removed it thinking it was added and I had no idea what parts to get to replace it. The pit man arm was replaced for the same reason. It had been modified to except a different drag link that used a idler arm. the hole thing was a night mare because it wasn't until I got a parts guy that new what was supposed to be there before I got the truck back together. I all most hauled her to the junkyard that month.

 

[LCAM-01XA]

Oh boy, one of THOSE situations I see Now it all makes sense, well good thing you got all the right parts on her now. And she still death wobbles? 2wd suspension, right?

 

[rlb245]

Yes 2WD! I tell ya truth I had about given up on it but sense I've joined this forum I have new hopes. There are so many great people here with there all about help and can do attitude. These people really think in and outside the box. With so many people coming at a problem from so many angles only good things can happen.

 

[LCAM-01XA]

The 2wd suspension is pretty simple and robust, as long as ball joints and steering linkage are in good shape I wouldn't think it can develop a death wobble, but who knows... The only thing loose on mine were the I-beam and radius arms bushings, well they were not loose loose but getting soft and causing the front end to wander ever so slightly on uneven pavement. Still, no death wobble under any conditions, even while flying down some dirt and gravel roads that must have made the shocks and bushings scream for mercy. I'd say replace your tired rubber bushings with new ones (I prefer polyurethane cause they're just easier to install and make the front end tighter, but rubber would be fine as well), while the I-beams are hanging down check the brackets for them on the frame cause their rivets sometimes get loose and allow some movement. Then when she's all back together hit a junkyard and grab the steering damper mounting brackets off a newer truck - it was not a factory option on your model year truck but it became one later on, mine came from a '92 crew cab 2wd and I've seen the same style on some mid-'90s Econoline (fullsize van) ambulances and moving vans as well, all 2wd too - drill two new holes in passenger side frame rail for one bracket, bolt the other one on what you call the drag link, buy a new $25 Monroe damper for a '92 F350 2wd crew cab from RockAuto, and you'll be in business. Finally give your swaybar new bushings as well (don't mess with the rubber ones there, just go for straight for polyurethane), and your front suspension will be about as good as it can possibly get, and better than factory courtesy of the damper. Have her aligned again after all the work is done, and if that doesn't cure your death wobble, then the truck is cursed!