Body wobble at high speed? Short story (2 Viewers)

[1hznewcomer]

Hey Mudders, got a lil gremlin I’ve been chasing and could use the hive mind input

80 series on 33’ muds, been working my way though some steering wobble issues. Initially a very bad steering shake, after replacing all tyres and a worn tie rod end, the shake still existed but was far less. Found my panhard rod bushes were pretty shot, so swapped them out. The steering wobble was gone, but now this new symptom has appeared.

Only when I reach 85kmph (55mph) or higher, the body of the truck wobbles. Like a constant, fast, repetitive wiggle. Can see it physically shaking the antennae, feel it through the steering, hear the s*** inside creaking about.

I have checked over suspension and steering components, also had a mechanic look to be sure. My gut is telling me when I had the alignment done for the new tyres, maybe it wasn’t the best job? Also noticed my fuel economy is worse since putting on new tyres/alignment

The body shake ONLY happens when I’m above 85km. It doesn’t occur at lower speeds, when I hit a bump, turning….

I’m thinking about rotating tyres front to back and going for a drive to see if the symptom changes. Could determine if it’s a poorly balanced wheel. The 80 pulls to the left quite heavily since alignment too. I know it’s meant to pull to the left for safety (I’m in Aus), but it is definitely more then it was previous new wheels…

THE QUESTION!
Should I take it back to the tyre shop and ask them to check their work? Do you have any suggestions what the culprit may be? I don’t want to be a dick and make the mechanics life hard, but I can’t shake the idea they have just done a rush job and this is the result.

Thanks for any input

 

[mudgudgeon]

It is not meant to pull to the left at all. The road crown may cause vehicle to drift to the left, not pull. Should easily be corrected with gentle input.

If it's happened since a wheel balance take it back have the balance checked, or rotate wheels.

Wheel alignment on an 80 will only adjust toe in/ out.

Check front wheel bearings arent loose.
Simple test, jack one front wheel off the ground, grab tyre at 12 oclock and 6 oclock, try and rock it toward/away from you if you feel any movement, bearings are loose. Repeat with the other side.
Don't rely on the mechanic, unless you have an estsblished record with them and know they are above average.

Ps,
you're in a gorgeous part of the world. I lived at Ruhls beach for a while 30 years ago. Agnes Waters was tiny. Just starting to grow

 

[mudgudgeon]

Re reading your description, sounds like a tire/wheel balance issue.

I would still check bearings.

 

[GeoRoss]

Definitely check the bearings.

 

[-Spike-]

Also check the REAR suspension bushings.

 

[1hznewcomer]

It is not meant to pull to the left at all. The road crown may cause vehicle to drift to the left, not pull. Should easily be corrected with gentle input.

If it's happened since a wheel balance take it back have the balance checked, or rotate wheels.

Wheel alignment on an 80 will only adjust toe in/ out.

Check front wheel bearings arent loose.
Simple test, jack one front wheel off the ground, grab tyre at 12 oclock and 6 oclock, try and rock it toward/away from you if you feel any movement, bearings are loose. Repeat with the other side.
Don't rely on the mechanic, unless you have an estsblished record with them and know they are above average.

Ps,
you're in a gorgeous part of the world. I lived at Ruhls beach for a while 30 years ago. Agnes Waters was tiny. Just starting to grow

Thanks for the reply, I’ll check the bearings then rotate. See if I can narrow it down. I agree about taking it back to the mechanic, I’m sorta new to town here so still learning who’s good with the tools.

Definitely love the QLD north coastline, brilliant fishing too. Spent many months in Agnes, you may not recognise it now. Population tripled after Covid!

Thanks again for the input

 

[Broski]

Sounds like tires to me.

 

[1hznewcomer]

Update!

Checked bearings - jacked up all tyres and felt for play, all solid.

Rotated tyres, front passenger to rear driver and vice versa. All tyres have vastly different weights for balance, just an observation.

Test dive at 90km for a few kms, issue seems to have faded greatly. The road wasn’t an ideal test, lots of lumps and bumps. But the body wasn’t shaking and the pull to the left in steer wasn’t present. So, all in all a good outcome.

I’ll head for a 20min cruise tomorrow and maybe try some wheeling. See if something comes loose or if we’ve solved the issue!

Thanks for the help!