Steering vibration and wobbles

[gotoy]

As per subject, this is occurring on my lj70 as quite random times:

1. At any speed over 40kmph the wobbles may occur.
2. During braking the wobbles may occur.

Lj70 has been converted over to kzj70 spec, but steering mechanism is the same.

To date the following has been done to try and track the source down, some replaced as wear and tear items:

1. Wheel balancing
2. Alignment
3. Disc's and pads replaced.
4. Tie rods replaced.
5. Bushings replaced.
6. Front wheel bearings

Nothing has been replaced on the steering rack.

Usual tyres are 33" MT and the wobbles on happen on tarmac.

 

[roscoFJ73]

Was the caster checked? That sounds like the problem.When I had a caster problem,it got worse when there was load on the rear axle from towing a trailer or just weight in the back.

I would try another wheel alignment shop,preferably one that specialises in 4wds

I dont think these have a steering rack,they have a steering box.

 

[gotoy]

Was the caster checked? That sounds like the problem.When I had a caster problem,it got worse when there was load on the rear axle from towing a trailer or just weight in the back.

I would try another wheel alignment shop,preferably one that specialises in 4wds

I dont think these have a steering rack,they have a steering box.

I been to 3 or 4 wheel alignment places.

Yes you are quite right, steering box, which has also been replaced.

 

[roscoFJ73]

Whats your steering damper like?

 

[gotoy]

Whats your steering damper like?

Only replaced about a year back.

 

[Estancio]

On my 70, I have sometimes experienced wobble/vibration from irregular tire wear.
Despite that absolutely everything else checks out OK.

 

[gotoy]

On my 70, I have sometimes experienced wobble/vibration from irregular tire wear.
Despite that absolutely everything else checks out OK.

The tyres have done about 20000km. They are rotated quite regularly.

I have not mentioned the ride height has been increased by 3" and the sway bar has been removed. However, previously I have been able to cruise along at 120-130kmph. I notice the wobbles start when I sometimes go over uneven surfaced roads.

 

[Eric Winkworth]

On my truck it was a lot of little things causing that sketchy wobble feeling, like the steering shaft U joints having a bit of play, a not so great steering damper, old worn suspension and bushings, pooched shocks... Once those items were replaced it tightened the truck up quite nice... Although going 120-130kmph over a fairly uneven road surface in a SWB cruiser is bound to pucker the a****** a little bit!

 

[gotoy]

On my truck it was a lot of little things causing that sketchy wobble feeling, like the steering shaft U joints having a bit of play, a not so great steering damper, old worn suspension and bushings, pooched shocks... Once those items were replaced it tightened the truck up quite nice... Although going 120-130kmph over a fairly uneven road surface in a SWB cruiser is bound to pucker the ******* a little bit!

120kmph on highway when I feel like a little blasting.

I have not looked at the steering shaft U joints.

 

[gotoy]

The steering damper appears to be quite stiff. Not sure on what difference this would make.,

 

[niwde11]

The steering damper appears to be quite stiff. Not sure on what difference this would make.,

it should be stiff especially if you try to push/pull rapidly in horizontal manner. according to my mechanic friend, not vertically coz its not an ordinary shock. different valving according to him.

did you change your caster bushings after lifting?
mine is only 2"lift and usually 2" lift dont need caster correction. but upon testing it, we change the caster angle. hth

 

[roscoFJ73]

I still think its a caster problem,ackowledging the fact it has been to 3-4 shops.

I might try altering tyre pressure and see what happens,although it may only hide a problem rather than cure it.

 

[gotoy]

I still think its a caster problem,ackowledging the fact it has been to 3-4 shops.

I might try altering tyre pressure and see what happens,although it may only hide a problem rather than cure it.

If the problem were a caster one surely the wobbles would be there all the time and not just intermittent like now.

Been to 3 or 4 shops for alignment and balancing only, if that helps.

 

[niwde11]

If the problem were a caster one surely the wobbles would be there all the time and not just intermittent like now.

Been to 3 or 4 shops for alignment and balancing only, if that helps.

didnt balance my 285/75r16 cooper STT on ROH blaktrak steel rims. no problem so far.

do also experience some wobbles especially hitting uneven roads on high speeds. but i didnt remove my sway bars. btw my ride is an LJ71(1kzte transplant) with less than a year ironman springs/shocks plus stabilizer.

 

[gotoy]

didnt balance my 285/75r16 cooper STT on ROH blaktrak steel rims. no problem so far.

do also experience some wobbles especially hitting uneven roads on high speeds. but i didnt remove my sway bars. btw my ride is an LJ71(1kzte transplant) with less than a year ironman springs/shocks plus stabilizer.

Sounds like the same as mine, but 40kmph producing wobbles does not seem correct to me. Furthermore the vehicle never had the wobbles for years...not like this and the sway bar been off for so long!

Castor bushings were just replaced a while back.

 

[roscoFJ73]

If the problem were a caster one surely the wobbles would be there all the time and not just intermittent like now.

Mine was intermittent,it would just take a bump or something to set off. Its quite normal,in fact,almost mandatory.

Been to 3 or 4 shops for alignment and balancing only, if that helps.

So they have checked the caster or not?
My shop told me they made the caster worse to diagnose it and then when they were satisfed it really was a caster problem ,they corrected it.
I had a 2 inch lift on my 73 series for 4-5 years and then one day out of the blue ,it got the death wobble.
It got that bad towing a trailer with a 1HZ in it ,I thought I was going to lose control slowing down on the freeway.
Try loading 150kg in the back and see if the wobble is worse.

 

[gotoy]

Mine was intermittent,it would just take a bump or something to set off. Its quite normal,in fact,almost mandatory.

Hmm...sounds just like mine.

I dont know if the correct caster bushings are in or not. How to test the caster?

 

[gotoy]

For you guys with death wobble - if you've replaced your bushings, damper and TREs it could be good to check your caster angle at an alignment shop. If you have negative or zero caster you're steering is "dynamically unstable" If you've lifted the truck at all and not installed caster correction bushings you may be out of spec. OME makes correction bushings but they lasted me a year and then split into pieces. Now I've got Super Pro bushings and they're doing much, much better.



Basically with positive caster the steering wants to return to center after a deflection from a bump or from the driver turning the wheels. Negative caster is the opposite. The wheels, once deflected, will want to continue to deflect. It gives the truck a very "light" and "wandering" feeling driving at speed. A steering damper helps with the shakes, but it can only patch up so much.

Just found this on another thread here on IH8mud.

 

[gotoy]

This might be a long shot but could the front springs have anything to do with it? They are donkeys old and were 2nd or 3rd hand from an 80series. Been meaning to replace, but not quite had the urge to do so.

 

[roscoFJ73]

Hmm...sounds just like mine.

I dont know if the correct caster bushings are in or not. How to test the caster?

I dont think you can do it at home as the required angle is around .45 degrees to 1.05 degrees on a leaf sprung cruiser.Not sure what it is on a coily.
Do you have a 4wd alignment specialist near you?

This might be a long shot but could the front springs have anything to do with it? They are donkeys old and were 2nd or 3rd hand from an 80series. Been meaning to replace, but not quite had the urge to do so.

The fact they give you a 3 inch lift makes them a prime suspect on its own.
Worn out shocks would probably make it worse.
The impression I got from the shop that fixed mine was that big things cause the death wobble and little things accentuate it.
Sometimes you can have 2 identical vehicles with the same everything,but only one will get a wobble.
Sometimes there is no rhyme or reason,its that finely balanced.