D1 Left Front Tyre Abnormal Wear

Id be looking at camber as well, some worn swivel bushes can change the camber quite considerabley but I would be putting money on the wheel base as Justin said, this is really common with Jeeps as well with similar results.

You also have to realise that most 2 lane roads have right to left camber built in which makes most cars with limited caster track left so you may be dialing in too much toe in when giving it the tweak that you posted earlier trying to combat the camber of your local roads.

If the toe adjustment is incorrect it normally will wear both front tyres edges rather than just 1 and the same with a bent drag link (tie rod) which will most likely also lead to the steering wheel being off centre and in extreme cases reduced turning circle one way or the other.

Worn steering damper or shocks will cause feathering and steering damper normally will give you a steering vibration like an unbalanced wheel at speed.

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Originally Posted by gazk

Thanks Graeme, I was thinking along those lines as all the bushes are original. I might just order the parts before I start pulling it apart. (I'm in Nowra and parts are not necessarily available at short notice.)
Would the panhard rod bushes also make a difference?

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The radius rod bushes can be checked using a big screwdriver to lever the arm about to get a good view of what's happening.
Worn panhard rod bushes will give wheel shimmy and wandering.

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Originally Posted by mcrover

Id be looking at camber as well, some worn swivel bushes can change the camber quite considerabley but I would be putting money on the wheel base as Justin said, this is really common with Jeeps as well with similar results.

You also have to realise that most 2 lane roads have right to left camber built in which makes most cars with limited caster track left so you may be dialing in too much toe in when giving it the tweak that you posted earlier trying to combat the camber of your local roads.

If the toe adjustment is incorrect it normally will wear both front tyres edges rather than just 1 and the same with a bent drag link (tie rod) which will most likely also lead to the steering wheel being off centre and in extreme cases reduced turning circle one way or the other.

Worn steering damper or shocks will cause feathering and steering damper normally will give you a steering vibration like an unbalanced wheel at speed.

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Thanks, the drift to the left happens happens on roads with little or no camber. There are no vibrations in the steering system. I've found the alignment data from just over 12 months ago and the final measurements showed individual toes at 0.0mm and total toe at 0.1mm. Even after that alignment it had a drift to the left on a flat road. As a Christmas present for the Disco I'm going to pick up a full set of front-end bushes on Friday, I'll let you all know the results in a couple of weeks.
Gary

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Originally Posted by justinc

Gaz,
I've seen thes D1's with shorter wheel base on the left than the right before, up to 18mm!!!
(One would think the alignment equipment would pick this up though)
This can cause crabbing down the road and wear front tyres enevenly like you describe. Run a tape measure between the axle centres on both sides and see if it is close..I bet it isn't.

We had to space them behind the trailing arm bush to rectify this.

BTW, most wheel alignment places are incorrectly toeing these IN. They should have 0 to 2 mm Toe OUT.

JC

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Hi again Justin, I measured the wheelbase on each side, they are the same given the tape measure positioning accuracy. (about 2mm difference) There is some movement in the radius arm bushes with slightly more on the left, so I think I'll start there and check the steering damper while I'm at it. Any recommendations on steering damper replacement ?

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Originally Posted by gazk

Hi again Justin, I measured the wheelbase on each side, they are the same given the tape measure positioning accuracy. (about 2mm difference) There is some movement in the radius arm bushes with slightly more on the left, so I think I'll start there and check the steering damper while I'm at it. Any recommendations on steering damper replacement ?

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QUICK, send you truck to the Dunsfold LR museum. It must be the only one within 5mm in existence!!:p:p

Seriously, that is a good thing. Yes, as mentioned by others I would toss the radius rod bushes if too much play, and use only genuine metalastic ones.

Steering dampers. I have a Bilstein one on mine, (previously a Koni one that I bent almost double:mad:(Why do RR's have their dampers in such STUPID places???))The bilstein one is fantastic. costs $$$ but worth it, even with my 33" mudders on steers fine.

JC

My ridepro steering damper is a fair bit cheaper than a billy and seems to work fine and Im running 235 85 16's but the quality of the Billy will always be among the best.

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Originally Posted by justinc

QUICK, send you truck to the Dunsfold LR museum. It must be the only one within 5mm in existence!!:p:p

Seriously, that is a good thing. Yes, as mentioned by others I would toss the radius rod bushes if too much play, and use only genuine metalastic ones.

Steering dampers. I have a Bilstein one on mine, (previously a Koni one that I bent almost double:mad:(Why do RR's have their dampers in such STUPID places???))The bilstein one is fantastic. costs $$$ but worth it, even with my 33" mudders on steers fine.

JC

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Hi again guys, put it back on the wheel alignment rig again yesterday for a quick check. The camber on the left has gone from being on the limit (-0.5degrees) in September 2006 to -1.25 degrees (Leaning out at the top) Time for a swivel housing overhaul and maybe a few other bits while I'm at it!

Just a follow-up to my tyre wear problem. Replaced the swivel pins and bearings on the left side (as well as the wheel bearings and all seals) and and it now drives straight with no odd tyre wear. I got interrupted by family needs over the New year and plan to do the other side soon as well as the radius arms. Interestingly I found an axle seal that had been put in backwards when I had the swivel housing seals replaced by a LR specialist back in 1995, expains why the diff oil level was always high and I needed to keep topping up the swivel pins (drained about 4 litres from the 2.7litre diff this time!)

I'm now a lot wiser about Disco front axles etc. Thanks for all the advice.