Wobble in the suspension

[donthekawguy]

When I got my truck it had a wobble when driving down the road. Not all the time but at certain speeds. The rear suspension was done first, new TA bushings, 4 inch springs, shocks relocated and new shocks. Still had the wobble. Next I rebuilt the front end. New 2.5 inch spindles, 2 inch springs, shorter shocks, new tie rod ends, ball joints, properly mounted PS box, draglink, idler arm, CA shafts, rotors and calipers. everything was replaced. I put on junkyard wheels and tires and still had the wobble. I thought it was the tires being out of balance. Yesterday I put on my brand new rally wheels with new tires. Still have the wobble. The only issue I didn't get to that I noticed was the radiator support is missing one bolt and the other isn't bolted to the frame. I don't think that is the issue though. This drives me nuts after spending so much time and money rebuilding all of the suspension and steering. It feels like a tire seriously out of balance but it felt the same with the junk tires and it's exactly the same with the new tires and wheels. The new ones were installed at a reputable shop o I know they are balanced.

[padresag]

does it have a 2 piece d/shaft? centre support
ron

[donthekawguy]

Nope one piece.

[padresag]

have you checked your firing order or the nut behind the steering wheel. you are running out of options. was the d/shaft shortened and ends out of sync. is there damage to the driveshaft. ujoints and are all of the motor and trans mounts good!!!!!!
ron

[donthekawguy]

I think it's something in the front end. It's a good wobble instead of a vibration from the driveshaft. It does have new u joints. I think I will check the mounts and maybe see if a rivet broke somewhere on the frame. It wobbles so bad at some speeds that the hood shakes back and forth. I'm also going to take it to a classic car restoration shop down the road and see if he will put it up on the lift and take a look. I'll have to take him for ride but he might be able to figure it out.

[padresag]

they are silly little questions, but when you are lost you have to think. there are lots of things that can cause it and it magnifies for some reason or other. there is always an answer for it .
did the wobble start before or after the ujoints were installed. there could have been a needle dropped and the joint forced together to put the locks in. that could do it
ron

[vin63]

You might be surprised how much resonance sheet metal can transfer if it is not secured. I would make sure the radiator support is mounted with new hardware and isolators (both sides) and then take it for a test drive. If it still wobbles, I would confirm a front and rear wheel alignment. I hope you find the issue soon.

[donthekawguy]

It was there when I got the truck. Same wobble after all the work has been done.

[joedoh]

hmm.

motor mounts? is it only at a certain speed?

look at your upper arms too, if memory serves someone had a strange alignment problem a while ago and found out they had switched the upper arms side to side, leading to a weird caster setting.

other than that I am stumped.

[donthekawguy]

I did have a front end alignment after I got everything put back together. And the upper arms are correct. I have a new bushing, bolt kit for the rad support so that is next.

[1966shortwide]

Have you ever jacked up rear suspension and check for bent axle"s.put jack stand"s under differential and let engine idle in gear and see if drum"s run straight and axle"s and wheel"s also.if you don"t see anything run the engine at a faster speed up to about where you noticed the vibration when driving on the road, and see if you feel any vibration .Be sure you have a jack stand under each side of differential when you do this.

[Captainfab]

The only thing that comes to mind for me also is possibly a bent axle flange.

[donthekawguy]

Originally Posted by Captainfab

The only thing that comes to mind for me also is possibly a bent axle flange.

Another thing to look for . Thanx John!

[cg285]

first part is communication as the goal here is to diagnose by airwaves without inspecting or spending any seat time in the vehicle.

describe what you call a wobble
does the steering wheel oscillate (rapidly) left/right?
or is it more like a vibration (bounce)?
if it's more like a vibration do you feel it more in the seat or steering wheel?
what speeds does it come in at and is it consistent with the speed?
does it go away, or lessen, with more or less speed?
does it take something to set if off like hitting a bump in the road?
or is it more like a handling problem where you are fighting the steering wheel?

things to consider:
typically things like worn bushings, bad ball joints, etc do not cause a wobble or vibration. they could accentuate it. i've had many vehicles come to the shop with front ends extremely worn but they drove normal. alignment is never a factor in any kind of "wobble" or vibration. if it is truly a "wobble" the majority of the times, in my experience, it was tire related. bent axle is a consideration but should be consistant

[donthekawguy]

Originally Posted by 1966shortwide

Have you ever jacked up rear suspension and check for bent axle"s.put jack stand"s under differential and let engine idle in gear and see if drum"s run straight and axle"s and wheel"s also.if you don"t see anything run the engine at a faster speed up to about where you noticed the vibration when driving on the road, and see if you feel any vibration .Be sure you have a jack stand under each side of differential when you do this.

I never thought of that. I was concentrating on the front so hard I was totally ignoring the rear. I am replacing the axles soon with new 5 luggers but before I do I will have to check that out.

[vin63]

Originally Posted by donthekawguy

I did have a front end alignment after I got everything put back together. And the upper arms are correct. I have a new bushing, bolt kit for the rad support so that is next.

…but, confirming a front to rear alignment will help spot any issues with bent wheels, axles, etc. in the rear.

[cg285]

Originally Posted by vin63

…but, confirming a front to rear alignment will help spot any issues with bent wheels, axles, etc. in the rear.

after the alignment heads are attached they are compensated for any run out in the wheel, axle or attaching mechanism so unless it is grossly bent it will not be noticed and will not show up on an alignment

[vin63]

Originally Posted by cg285

after the alignment heads are attached they are compensated for any run out in the wheel, axle or attaching mechanism so unless it is grossly bent it will not be noticed and will not show up on an alignment

I'll be sure not to use the shop you go to for alignment. When a customer comes in complaining about a wobble, darting, wandering, pulling right or left, etc., we take it for a drive with the customer to identify the issue. We put it on the rack and do a complete inspection as part of the alignment process. Then do a test drive after to make sure the issue is resolved. Just doing a static alignment without experiencing or addressing the customer's issue does little to fix any problems and is bad customer service.

[cg285]

Originally Posted by vin63

I'll be sure not to use the shop you go to for alignment. When a customer comes in complaining about a wobble, darting, wandering, pulling right or left, etc., we take it for a drive with the customer to identify the issue. We put it on the rack and do a complete inspection as part of the alignment process. Then do a test drive after to make sure the issue is resolved. Just doing a static alignment without experiencing or addressing the customer's issue does little to fix any problems and is bad customer service.

the comment was addressing the fact that an alignment itself will not show a bent axle.
i wasn't trying to step on your great customer service toes.

[old cool]

Please don't leave us hanging if you solve problem. Some thoughts for consideration are drum and wheel weight distribution and I'm not referring to wheel weights for balancing a tire. One of my wheel studs had a yellow dab of paint on it. I read somewhere that this old school marking was for positioning the wheel based on the valve stem opening. Don't laugh, not my idea.
Also, worn slip yokes may affect spin of drive shaft. Im going to look at mine when weather warms. I see recommendation for packing yokes with grease to help clunking (temporary fix). Just wondering if this would also affect smoothness of driveline???
Good luck and don't forget to update.

[donthekawguy]

I'm going to drive it to work Sunday and see what MPH it wobbles. If it's light enough I might try to get a video. It's not the drive line, it has a one piece. It wobbled the same before I swapped out the brakes and suspension so I'm leaning towards rear axles or wheels. I hope to have the axles swapped out for new 5 luggers next week and of course I will have to get the new wheels and tires on also. If that doesn't work I will put in the new rad. support bolts and start checking the rivets and motor mounts. I'm also going to put on a front sway bar soon. That will either help or make it worse so we'll see.

[Rac65]

My 65 used to have a severe shimmy if you hit a bump at about 45 mph. It would shake so hard it was scary. If you sped up or slowed down it would stop. I checked everything I could think of but couldn't figure it out. When my bias ply tires wore out I decided to put radial tires on it and for whatever reason it stopped. That was back in the eighties and when I took it off the road in 2009 it was still ok.

[Captainfab]

This reminded me of something else and it doesn't apply to just bias ply tires. I have seen radial tires do some weird things when the plies start to separate. You might take a good look at your rear tires, since you said you have changed the fronts a couple times.

Originally Posted by Rac65

My 65 used to have a severe shimmy if you hit a bump at about 45 mph. It would shake so hard it was scary. If you sped up or slowed down it would stop. I checked everything I could think of but couldn't figure it out. When my bias ply tires wore out I decided to put radial tires on it and for whatever reason it stopped. That was back in the eighties and when I took it off the road in 2009 it was still ok.

[donthekawguy]

Originally Posted by Captainfab

This reminded me of something else and it doesn't apply to just bias ply tires. I have seen radial tires do some weird things when the plies start to separate. You might take a good look at your rear tires, since you said you have changed the fronts a couple times.

It did have the wobble when I first got the truck but I did get a set of used tires for the rear soon after getting the truck. I'm hoping to have the axles swapped out next week some time and I will know more.

[bj383ss]

My 79 Caprice had a wobble and I found it during a chassis dyno run. It only occurred in 3rd gear at high speed. So when they were doing the dyno I had them do a pull in second gear to avoid the wobble but it was to short of a run to get any data. So they tried a 3rd gear pull and one of the techs noticed the right rear wheel was off. We swapped for a front wheel and the wobble went away on the chassis dyno. So I had to buy a new wheel and that one became the spare wheel. Once it was on the chassis dyno it was very easy to see one of the rear wheels was bent. Not even sure how it got bent. As I bought them brand new.