Caster angle debate, am i loosing it! or going nuts

[crash520]

Team,
Ok, so I have a wheel alignment done on my 99 GU 42TD coil cab chassis.
Toe in/out looks good by all accounts,
Camber LH = -00deg03’ RH= +00deg30’
Now for the Caster angles
LH = +01deg06’ RH= +01deg32’

The ride has aftermarket coils but from what I can tell it doesn’t sit much higher than a normal C/Chassis in the front but it is high in the rear

At 80klm is has a steering wheel shake, at 100klm is smooth, not huge but its annoying, it always pulls to the left, again not by much but it’s annoying. Inside and outside edges are slightly scalloping

I took the ride and the wheel alignment results to a well known 4wd repair/aftermarket sales company today to ask them about offset bushes for the trailing arms and if I needed them and was told that rectifying the caster to the factory 3 Deg would not change anything except remove tail shaft vibration only and that if they put offset bushes into my ride the best they could hope to achieve would be something near 2 deg.
So, can someone tell me I’m not going nuts and can you guys give me some advice as to the direction I should take,,, please

Greg

[crash520]

http://i3.photobucket.com/albums/y84/crash520/Crash%20520%20Nissan/frontrightatire.jpg photo of front right hand tire wear

[Bigrig]

http://i3.photobucket.com/albums/y84/crash520/Crash%20520%20Nissan/frontrightatire.jpg photo of front right hand tire wear

Give me a wee while to get back to the laptop (I'm on my iPhone) and I'll post up some info, but all to do with your second post (the picture) - your tyres look like they're scalloping which is common symptom of a shot shockie. That would also explain the vibration at 80k's - castors in the front end have nothing to do with tailshaft vibration (that is a separate balancing issue and commonplace - my tailshaft needs balancing as it creates a harmonic vibration at about 70-80 klms as it's dropped a weight).

I'd be looking at the shocks as a first point of call, possibly the tyre itself, although that's rarer ...

[crash520]

Thanks BR,
ok, i tightened up the RH wheel bearing and this made a little difference, the tire wear in the photo's are of when i purchased the ute, i have done almost 10k after a tire rotation and they dont look anything like the pics so I wonder if it was tire presure and lack of care before, the pressure was down to 25psi. there is still some 'slack' in the steering sytem somewhere, if i grab a wheel adn wobble it back and forth at the 3 and 9 there is a clunk, i had a mate under it looking for loos tie rod ends etc but he couldnt see anything. The LH wheel bearing could be a little loose still so i'll tighten it and recheck, bit by bit i'll get there.
Thanks again

Greg

[Dan78]

I have had the same problem with the truck pulling to the left. I have also had it down to the mechanic 3 times no to fix the hub seal leaking. This time the mechanic called one of mates at truck align and asked him about the offset kingpin that was installed by a wheel alignment joint. He said let me guess, you keep blowing left hand seals!!!

He said that the common mistake is they only do the offset on the top kingpin which puts a major strain on the bottom bearing. What he is supplying me now, is a top and bottom one which puts both of them into correct alignment and should fix my toe in/out problem and stop it from pulling to the left.

I don't know if this is the problem that you are having, but it sounds pretty close, except for the blown seal on the hub.

By the way, it took 40,000km for the hub seal to blow out after this was installed, and the guy said that it would keep on happening because of this.

Daniel

[Bigrig]

Thanks BR,
ok, i tightened up the RH wheel bearing and this made a little difference, the tire wear in the photo's are of when i purchased the ute, i have done almost 10k after a tire rotation and they dont look anything like the pics so I wonder if it was tire presure and lack of care before, the pressure was down to 25psi. there is still some 'slack' in the steering sytem somewhere, if i grab a wheel adn wobble it back and forth at the 3 and 9 there is a clunk, i had a mate under it looking for loos tie rod ends etc but he couldnt see anything. The LH wheel bearing could be a little loose still so i'll tighten it and recheck, bit by bit i'll get there.
Thanks again

Greg

Sounds right on the tyre mate - low pressure etc could have caused it. That clunk in the steering could be the steering arm and/or pitman arm joints also, as well as tie rod. Check all those arms an bushes and hopefully it's not your steering box on it's way out - but I'd be betting a blown rubber/bush on the arms.

[Finly Owner]

Patrols have a problem with wheel wobble, it can be caused by: shocks, steering joints, sway bar bushes, panhards bushes, spring bushes(if leaf), wheel bearings, pivot-knuckle-king pin bearings, and the last to be replaced is the dampner as this does not cause the wobble.


Tim

[-ET 4wd-]

Mate had it happen in his GU coily ute and all we did to fix that was remove the shims from the L/H side kingpins.
He has a 2 inch dobinsons lift and 33 Pro-comps, the scolloping would be a shock for sure or a bit out of balance or both!

Steve.