Outer Limits 4x4 Board

gday

i got a 4in lift done to my coil ute, and when im driving all of a sudden it will start uncontrollable shaking dead on 70km/h, but (this is what i cant understand) when i let the tyres down to about 20psi it drives fine. Castor plates and adj panhard rods are fitted and i have replaced the king pin bearings, steering damper, rear unis and the font diff housing.

I was talking arb at landcrusier park last month and he was saying about installing a half drop box because he throught the radius arm bushes would be cracked. but i had a look and they look ok.

If anyone could help i would appreciate it heaps as i have no idea.
Thanks

Whats your tyres like??????????

Looks like you have already checked all the usual suspects like bushes, steering components,..
You shouldn't need castor plates for a 4" lift IMO. I suggest you go to an alignment place and get a castor reading. Excessive castor can cause this problem.

I had the shudder problem with a 5" lift and castor plates (5.5 deg) which resulted in a 4.5 deg poitive caster. I swapped all my bushes (both ends for radius arm, panhard rod) and re-balanced the tyres. All this didn't fix the shudder. When I replaced the caster plates with 3 deg offset bushes, my problem went away.

Hope that helps
Joachim

Maybe you could get a lend of someones tyres. Sounds like tyres to me but......

You should get adjustable rear trailing arms (Just the upper will do fine) if you haven't already. Then when you fit them or if they are in already, you have to make sure that the angle of the tail shaft coming out of your centre hand brake is the same as the angle going into your diff. This is most important otherwise you get vibrations and/or it will wear uni's much quicker (unnoticable vibrations). I can give you a better explaination why but the Mrs is calling.

Shane

Let us know what it ends up being.

EDIT Yeah I 3rd those leading arm lowering brackets as well BATC who makes this stuff recommend them. I can deliver them to you for $250 if you can't find any one local, IF THIS IS THE PROB.
They are strong, can take a beating. (In a shorty they do effect your ramp over a little.)

im gunna second the arb guy about using a drop box..lowers rear of radius arms and will unload all the strain of the rear bushes and allow u to use genuine factory rubber front radius arm castor bushes. any minor imperfection or slight misalignment u may have in the front end will be amplified if ur radius arms are steeply angled as would be the case with a 4 inch lift.

i recently fitted drop brackets that lowered my radius arms about 100mm to compensate for the 5 inch coils i have..im using full factory bushing and my truck is handling and steering like a totally different vehicle. regained all the lost flex too in the front end due the angle in the arms not allowing any more flex outta bushes etc..

wheel bearings?

Tires balanced?

sorry about the late reply

yer tyres are abit on the worst side, but i did change tyres with a mate and no difference

i had this problem really bad with a five inch lift, but it was a eighty and i couldn't drive out of it. We did all what you have done and still the problem. By changing the castor correction angle the shaking was greatly reduced. What is your castor bush angle?

Snatch

might be wrong here.. but castor plates may not be suited for your suspension setup.. try some 2/3 degree bushes instead and see how that goes..

Also check panhard and steering linkages .. simply jack both wheels up and have someone hold one side while you turn the other side and move it up and down (camber) to see if anythings loose..

TOM


(so far ive seen a few cases... panhard was bolted up wrong.. wobbles every bump , another was wobbles after a certain kph - 70 was due to castor plates - replaced with bushes and went fine, and another was my steering arm which had a badly worn out balljoint end which sent my car into the wobbles)

its 5.5 deg caster plates, thanks to everyone who has replied, i will change the caster and get back to ya

thanks again.

welchy wrote:its 5.5 deg caster plates, thanks to everyone who has replied, i will change the caster and get back to ya

thanks again.

Prob is that 4" is between busches and plates, but the most commen prob is ballence, get your tyres ballenced ON the car at a truck place

first you break the hilux and now the poor patrol

I had the same problem when I put my dropped radius arms on and over corrected the castor. The steering geometry on a patrol is on the border line as it is and doesn't take much to upset it. Get rid of the castor plates or get 3 degree plates. 3rd's productions also make 3 degree dropped radius arms.

Another option for correcting your castor on a 4 inch lift is to weld plates over your originals and redrill holes to suit a 4 inch lift. The holes will be on the edge of your original castor plates that hold your bushes in. You will need longer bolts then. (Can someone else explain it better).

Do you have adjustable trailing arms???????????

What he's trying to say is remove your radius arms and weld plates over the original mounting brakets on you diff effectively blanking the holes. Then just redrill them to suit whatever castor you would like. More stable than bolt on castor plates as there are still only 2 bolts in each radius arm. Also he's asking if you have adjustable trailing arms cause if your truck is misaligned and crabbing down the road it will effect the handling of the vehicle.

bogged wrote:wheel bearings?

Tires balanced?

A 4 ich lift will normally only need 2 deg bushes NOT plates.

I aggree with bogged , checked the wheel balance , Especially on the nissan they are so sensative.... Sounds strange but you may find its just that.

The Big Green Meany wrote:

bogged wrote:wheel bearings?

Tires balanced?

I aggree with bogged , checked the wheel balance , Especially on the nissan they are so sensative.... Sounds strange but you may find its just that.

I learnt that ballance is imperitive is after rolling my front drivers side tyre of the rim after it sliped off a rut in a bog hole, it had a bit of crap inside and spun the tyre around as well as rip off the weights, coming home I developed a death wobble so bad, 1/4 turn each way on the wheel, uncontrollable over 60km and so severe, it would break a finger if ya stuck it in.....put the spare on and fixed it, took the bad one to pull off the rim, clean out and rebalance, refitted and no probs.

If it was the tyres he would have to be very unlucky because he did swap tyres with a mate. I have 3 degree castor correction bushes if you needed to go in that direction and it is less permanent.($100)

Trailing arms??

its certainly not an unusual thing, shit mine did it for a while tightened shims or pulled on out or something in the front and she was sweet for a while now wobbling again......

last resort is get the swivel hubs bearings all seen to in front then....dunno...

i have the drop boxes replaced bushes blah blah blah and still...... regularly balanced to......

good fun
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