Wheel alignment

[Duarte19]

Hi Guys,

I have a wheel shimmy at 80-90kmh, need to get wheel balance and alignment (toe) checked, any recommendations besides the bobjanes/Kmarts etc?

thanks

[russ55]

Widetread in Ferntree Gully did a good job on mine.

[BigJon]

Shimmy might be wheel balance, but could also be myriad other things. For example, panhard rod bushes, shock absorbers, swivel preload, etc, etc.

[ADMIRAL]

Shimmy might be wheel balance, but could also be myriad other things. For example, panhard rod bushes, shock absorbers, swivel preload, etc, etc.

Ditto, the very fact the shimmy is speed related points to things attached to wheels first, rather than wheel alignment. I would check the wheel bearings for play, and the tyres for runout ( eccentric )as a first stop.

[Duarte19]

thanks all,

Driving me nuts trying to find this shimmy,

I have replaced the panhard bushes with superpro - improved a little

check swivel preload, set to 3.5kg on one side and 5kg on the other, was previously less than 1.5kg - improved greatly

but i still have a small shimmy at 85kmh, on a staight flat road i get no shimmy, but if i hit a bump at that speed instant shimmy, also, slight bend in the road doing 85 ish, shimmy again

Should I revisit the swivels and set the other side to 5kg so they are the same?

I also had the toe set to 0, improved a tiny bit again...

[one_iota]

How old is the steering damper? A bad one can cause these symptoms.

BTW the "toe out" should be 3mm from memory.

[Duarte19]

steering damper is age of the car, 2002/90k km

I have been looking at the ironman/terrafirma dampers, worth replacing?

thanks again

[one_iota]

It won't do any harm if you can afford it...it sounds like you've tried everything else....frustrating!

As for the brand I can't advise but also replace the associated washers and bushes if you do it.

[JDNSW]

If replacing the steering damper fixes it, you have simply masked the problem - best to find and fix the problem(s) first. Some of them you have already fixed, but I would carefully check for any steering free play (for example, I found the universal above the steering box on mine was slightly loose!) especially tie rod ends and for any free play on the radius arm bushes. But as suggested, the speed related shimmy does suggest wheel related - first step would be wheel balance, and check for runout, then check for loose wheel bearings - or even loose wheel nuts.

John

[weeds]

mine ended up being tie rod ends...

i run 1mm toe out...well thats what i tell the shop doing the ilignment, i always thought toe out was listed as 0mm - 2mm

[garyper]

Mine was the front shockies. Heaps of problems when I first fitted OME, drive fine on smooth road then hit a bump and shimmy big time. Fitted some Terra Firma Big Bores and problem went away.

Cheers
Gary

[Duarte19]

bit more background,

Has always had this problem, I have only owned it 2months

Checked all tied rods, bushes etc as best i could

Has 33" coopers STT's and a 2" lift, will I need a RTC steering damper purely for the STT's?

It is speed related but doesn't always do it, had the wheels balanced and it, again, improved things marginally...

[Duarte19]

I have gone ahead and ordered a new steering damper

One thing that came up on the alignment was the castor being 0, didn't think a 2" lift would be enough to cause this, might be worthwhile looking at slotted swivels?

[BigJon]

Has 33" coopers STT's and a 2" lift,

Big tires that are hard to balance won't help. Being Coopers with a reputation (well earned) for tread delamination would make me doubly suspicious.

The 2 inch lift will have reduced the castor to near zero which will also lead to shimmy issues.

[n plus one]

I've got a minor shimmy in mine at the moment - everything else has checked out OK so I just picked up a new OME damper to see what that does.

The shimmy turned up with my 255/85r16 - doesn't seam to balance out and is so minor that I can only notice it on freeway smooth roads.

I'll let you know what I find - will also get everything triple checked by someone else in a couple of weeks time too just to be sure.

[justinc]

If the shake is there on bends and bumps then would pay to scrutinise the radius rod to differential housing bushes, if they are soft or collapsing this WILL cause a horrific shake, even worse sometimes when going downhill on a bend...

DO NOT fit urethane to these, genuine only is the way to go. NTC6860 are the better ones. NTC 6860 - Radius Arm Front Bush, Later large type (http://www.pegasusparts.co.uk/ourshop_90073/prod_1834402-NTC-6860-Radius-Arm-Front-Bush-Later-large-type.html)

JC

[n plus one]

If the shake is there on bends and bumps then would pay to scrutinise the radius rod to differential housing bushes, if they are soft or collapsing this WILL cause a horrific shake, even worse sometimes when going downhill on a bend...

DO NOT fit urethane to these, genuine only is the way to go. NTC6860 are the better ones. NTC 6860 - Radius Arm Front Bush, Later large type (http://www.pegasusparts.co.uk/ourshop_90073/prod_1834402-NTC-6860-Radius-Arm-Front-Bush-Later-large-type.html)

JC

Thanks JC - although not my issue (this time) as the RA bushes are brand new.

Playing around under the truck today while fitting the new damper I noticed two things - 1. My trailing arm to chassis bushes are showing some minor wear (lift related) and 2. There appears to be a (small) amount of play in my steering box.

Interested in your thoughts on this.

[rick130]

If the shake is there on bends and bumps then would pay to scrutinise the radius rod to differential housing bushes, if they are soft or collapsing this WILL cause a horrific shake, even worse sometimes when going downhill on a bend...

DO NOT fit urethane to these, genuine only is the way to go. NTC6860 are the better ones. NTC 6860 - Radius Arm Front Bush, Later large type (http://www.pegasusparts.co.uk/ourshop_90073/prod_1834402-NTC-6860-Radius-Arm-Front-Bush-Later-large-type.html)

JC

Justin, those look like the triple sleeve type ?

I prefer the Defender/two sleeve type, they allow much more articulation than the Disco version (which acts like an anti-roll bar, of sorts as it increases roll stiffness by increasing bush stiffness) or Super Pro's urethane ones which are so easy to fit and nearly allow as much articulation as Haultech's old Holey Bushes, or at least a little more than the two sleeve genuine rubber ones.

[rick130]

A shimmy like this can also be caused by a dead circuit/s in one of the front dampers/shock absorbers.

Have had this happen on the Defender, and Mr "I used to be employed in a previous lifetime to tune suspensions" didn't pick it straight away either.
It was a case of deliberately hitting the same series of bumps at various speeds over two days before the penny finally dropped after checking everything else. :angel:

Rebuilt the front shocks and all fixed.

I've also had a poor dynamic wheel balance cause a bad shimmy in an F100 under brakes. It was so bad it would almost turf me out the driver window when hitting the picks. Numerous wheel balances didn't help, until one day the tyre shop nailed the balance properly after I insisted it had to be a dynamic balance problem.
Instant fix.