Highway death vibe..

[Cruiserhead05]

Ok, so in the last month or so i think i've posted 1 or 2 threads on this topic so please forgive be.....but with my recent trip this weekend i have a little more info on my shimmy problem and was hoping for some help trying to pin my problem.

Drove 2.5hrs to lexington, at about 60 and above i get a vry strong shimmy in the truck. With increased speed, increased shimmy. For the majority of the trip the shimmy was very evident but randomly would disappear for several minutes at a time and the overall ride was fairly smooth. The shimmy can be felt very strong in the seat, seen in the dash, and also can be seen the in both brake/ gas pedal(everything shimmies from side to side). It is not extremely strong but can be felt and seen in the steering wheel.

I do understand that with OME Heavies and no bumpers i am going to have a stiff ride and thats fine but the shimmy is just not right.

I am thinking and hoping it is simply a steering issue. I.E. tierod ends and rods
as last year when the truck was aligned they said the TRE's were frozen in place and needed to be heated to be adjusted.

Thanks, Brandon

Sorry if this doesnt help a whole lot. i just figured more detail would help to narrow things down.

 

[ultimauk]

Ok, so in the last month or so i think i've posted 1 or 2 threads on this topic so please forgive be.....but with my recent trip this weekend i have a little more info on my shimmy problem and was hoping for some help trying to pin my problem.

Drove 2.5hrs to lexington, at about 60 and above i get a vry strong shimmy in the truck. With increased speed, increased shimmy. For the majority of the trip the shimmy was very evident but randomly would disappear for several minutes at a time and the overall ride was fairly smooth. The shimmy can be felt very strong in the seat, seen in the dash, and also can be seen the in both brake/ gas pedal(everything shimmies from side to side). It is not extremely strong but can be felt and seen in the steering wheel.

I do understand that with OME Heavies and no bumpers i am going to have a stiff ride and thats fine but the shimmy is just not right.

I am thinking and hoping it is simply a steering issue. I.E. tierod ends and rods
as last year when the truck was aligned they said the TRE's were frozen in place and needed to be heated to be adjusted.

Thanks, Brandon

Sorry if this doesnt help a whole lot. i just figured more detail would help to narrow things down.

OK, I've had the exact same problem and lucky for you I also have OME Heavies, shocks, and Slee tie rod. I had this shimmy problem in various different forms.

First was stock with worn shocks and springs. This is why I installed the OME, but it didn't help.

Next was heavy shimming while braking and this was solved by replacing all calipers, but it didn't fix the normal driving down the road shimmy.

Next I replaced my bearings all around and it helped a little, but (EDIT: after ~8,000 miles) still really bad while braking on level road and down hill.

I fixed the level road shimmy and some of the down hill by paying special attention to the bearing torque specs.

Now that I've replaced and inspected basically everything I only experience shimmy (slightly) while breaking downhills.

Now that I threw all of that at you, you sound like you have a bent drive shaft.

 

[Cruiserhead05]

Ultimauk,

A drive shaft/ and or wheel bearing probably makes sense. I was looking over some stuff and turns out, when my local shop put the OME heavy on, and new radiator, they also did an alignment job. The more i think about it, it makes sense that this bad of a shimmy, if it was coming from my steering, would be strongly felt through my steering wheel but the wheel itself is pretty steady but does have some slight movement.

 

[Safado]

Tires...What are you running and when was the last time you had them balanced. What have you done off road since then? Did you air down?

 

[Cruiserhead05]

So, how do you check for a bent drive shaft short of removing one at a time and driving it out of the highway with the CDL switch on? or is this the easiest way to go about it?

 

[Riley]

wheel bearings

 

[Cruiserhead05]

Safado, thanks for the input but the tires were balanced last tuesday and alignment was done a month ago, this problem has been felt for about 8 months now

 

[Cruiserhead05]

Is there any logical reason why the truck would get really smooth for a minute or two at a time? On the way home today i remember it shaking at 65, took the truck to like 72 and the shimmy only got worse.....then when the shimmy would go away, i took it to 80mph and it was really quite smooth. If it was infact a bent shaft, would the issue disappear like that?

 

[Big_Moose]

I hate to mention this, but have you checked the obvious culprits - unbalanced tire, bent rim, lost tire weight, etc

To test the tie-rods - climb under the cruiser, grabe the tie rod (connects the left & right knuckles together) and / or the drag link (connects steering box / pitman arm to left knuckle), and shake up / down - left / right. They may twist, but if loose / worn will move all over the place.

To test wheel bearings: Jack up the front end / tires (or one side at a time...) off the ground, grab the tire at the 12:00 / 6:00 positions and shake the tire (push at 6 / pull at 12 // push at 12 / pull at 6, etc). If you can move the tire, then the wheel bearings are loose - and should be adjusted.

Other things to check would be the drive shaft - grab & shake the front & rear dshafts, they will have some rotational movement / play, but any excessive movement is generally a sign of worn u-joints.

You could also check the front control arms & bushing for wear, by tryng to move / shake them, any excessive movement with minimal force generally equates to a worn component.

But, it seems like you are describing a constant shake / vibration, which would be associated with tires, then bearings, then shafts........

Good luck

 

[Cruiserhead05]

Ok i just went out and jacked up the truck. The front passenger side tire seems fine, very tight while the drivers side does have some very obvious play in it. IT almost hard to see how a slight amount of play on the wheel could create such a shimmy, but i guess when its all moving 70 mph+ things tend to get multiplied in their effect.

 

[Safado]

Not to get too stuck on it, but it can really depend on what size tire you have...what are you running? Anything large? My vibration happend after having them balanced, but learned that if the tires aren't hot when balanced, there could be a difference in performance. If you balance a cold tire, it will be true until it gets hot on a freeway run and changes shape slightly. This is what I'm trying next.

 

[Cruiserhead05]

Safado, its in the sig line. 285/75/R16 BF Goodrich All-Terrains. I do understand what you are saying and it makes sense. Although the shimmy was there when the truck was on stock suspension and stock tires and its the same now, makes me believe its something else.....dont get me wrong though, i do value your opinion. If i go in to have the bearing done i will push for this as well.

thanks, B

 

[semlin]

you mentioned your tie rod ends were frozen. I find that hard to reconcile with the fact you had an alignment a month ago unless your toe in was perfect after upour lift. I just finished replacing the relay and tie rod ends on my truck. I suggest you check your tie rod ends for play then pull your tie rod and free up the ends and rethread them or replace them as needed. Then do the same for your relay rods. then go get another alignment.

you mentioned "obvious" play in one wheel. Tighten up that wheel bearing.

If you are really keen, drop your drive shafts and get them balanced at a drive shaft shop.

Once that is done. Report back.

 

[Safado]

Although the shimmy was there when the truck was on stock suspension and stock tires and its the same now, makes me believe its something else.....
thanks, B

NP, This information would have shut me up a long time ago however.

 

[mabrodis]

You are on the same rims as before right? I would say tires (my FJ40 had messed up tires and even getting them rebalanced didn't cure everything, new tires did however) but these are already different tires.

Do you have another set of tires/rims you could throw on there for a day and see how that affects it?

I'm still leaning towards something tire related. The fact that you can feel it in the driver's seat and also in the steering wheel to me suggests a mid-vehicle issue. The most obvious of which would be driveshafts (like previously mentioned). Grab the front driveshaft especially and yank it all around. Then I'd remove the rear driveshaft all-together (you have the CDL switch you say), drive with only the front driveshaft for a day, is it any different, better, worse, etc. Then put in the rear and pull the front, how does it drive then. That would atleast prove those parts right or wrong.

Good luck...things that seem to be knuckles aren't always though. I rebuilt the entire frontend on my FJ40 trying to get it smoother, etc...didn't fix it one bit, it was all tires, and even with rebalanced tires, it wasn't perfect, tires can still easily be out-of-round, which balancing does not fix, they can try to compensate for, but they aren't putting weight on the tires, so compensating for a far-out tire bulge is useless because when you drive on it, that bulge won't be far out there probably...I'd say get the tires balanced at one of them fancy dohickie machines, KZ9000-double-humper-cross-bred-wild-child things, but that's like $20-30 per tire, for something that might not be your problem...

Good Luck..

 

[Cruiserhead05]

Mabrodis,

You raise some good points but i dont totally see how it could be tire related as the shimmy was around when i was running stock suspension, stock wheels and stock michelins....the shimmy is the same now and i am on OME heavy, stock wheels, and 285 bfg's. The fact that the shimmy was unchanged with the tires, wouldnt it mean the tires arent the problem?

 

[ultimauk]

Is there any logical reason why the truck would get really smooth for a minute or two at a time? On the way home today i remember it shaking at 65, took the truck to like 72 and the shimmy only got worse.....then when the shimmy would go away, i took it to 80mph and it was really quite smooth. If it was infact a bent shaft, would the issue disappear like that?

"Is there any logical reason why the truck would get really smooth for a minute or two at a time?"

Are you sure you haven't been driving my 93?

I've seen this vague shimmying also, the shimmy disappears on the flattest of roads, but even this can mislead you because cross winds also induce shimmying on the same level roads. This was the original prompt for the OME heavies, i.e worn suspension.

I've also hear rumors of 93 -94 having some sort of steel inserts in the aluminum wheels and they require different torque specs, is it possible that we might have different spec-ed wheels, as in mix and match?

If you figure this monster out please PM me.

 

[Kalawang]

Cruiserhead05,


Put your LC on a lift with someone in it and have him run it in drive up to "... 60 and above ..." while you look at the drive shafts for vibration. It will be very obvious if there is any. Likewise look at each wheel while it is spinning at "... 60 and above..." to see if any of them shimmy or shake. That too will be very obvious to your eye. Be sure to pick the right kind of lift. There are several types.

If you have a wheel out of balance, before you try balancing it again, run your hand around the sidewall, inner and outer, and check for even the slightest bulge, or the beginnings of ply separation. It's a valid check even if you don't air down your tires. We sometimes hit bumps we think did no damage, or load the vehicle with lots of fun stuff and fun people. The LC might be able to handle it but the tire might have failed the test. Likewise look carefully at the wheel for deforming or damage.

Be sure to give each wheel a vigorous shake before letting the lift come down fully. Loose wheel bearings will allow the wheels to move and you will feel it.

If this doesn't identify and isolate your problem, it's time to think some more.


Kalawang

 

[Cruiserhead05]

Bear,

the shimmy started months and months ago, way before i did the lift and tires....this is the only thing that leads me to believe that it is not a tire/wheel issues. also, i have done caster correction, as i said earlier thye fron drivers side wheel does have play in it...i think it may be a wheel bearing problem.
B

 

[Texus]

hmmm

well, if there is play, than change that s*** now... would be bad if that wheel came off... well maybe.. so I'm told...