GU Shimmy Questions

[morkz]

Yeah i had drop boxes and they fixed my shimmy problem with the GU ended up taking out the OME bushes and putting genuine nissan ones back in.

Got my drop boxes off climax industries about $450

[BOB_1]

I seem to have fixed a fair bit of my problem, I had something not on the first list I made, A bit too much slack in the steering box, All I did was undo the nut on top, tighten the screw a bit and and did the nut back up, Far better, now to get a rear balance again and problems should be sorted.

[liftkit8]

check your kingpin bearins in the top and the bottom of the knuckle try removing the 4x 14mm bolts pop out the top one and remove the shim in there i find this helps them a bit

does this work???

[Dee]

check your kingpin bearins in the top and the bottom of the knuckle try removing the 4x 14mm bolts pop out the top one and remove the shim in there i find this helps them a bit

does this work???

read the rest of the thread... The answer lies within.

[ats4x4dotcom]

First thing toward fixing it is get rid of the shitfully useless RTC steering damper, they have less hydruolic force than the standard nissan one, and fit a good quality heavy duty one, we have a Monroe one we use for budget, with 80% more force than the genuine unit, and we use Fox dampers if budget isnt as much of an issue.

Also, try running the vehicle with some more toe in wound in, for 33-35" tyres we use 3-mm, and 4-6mm for 37's as a general rule, and we normally set the front ends to run 1-1.5 deg neg camber as well.

Superior make a very slim drop box, and you need to trim the top off the washers, if you have 3" or more of lift, and the arms on the correct horizontal line work much better as well.

2-2.5 deg castor is what your aiming for.

[bazzle]

To check panhard bushes cup your hand around joint and get someone to push car side to side. You WILL feel the play.
Main cause of shimmy other than tyres.
Do same test on tie rods and wheel bearings.

I ran the Superior slim drop boxes too with geround off washers. Worked a treat to fix binding on end of radius arms.

Bazzle

[Beefcake]

this whole shimmy has been a thorn in my side aswell. Bought my patrol brand new last march and had OME suspension including steering damper and castor bushes fitted before taking delivery and has had steering wobble from day one. Nissan told me it was the cr@p tyres they fitted from factory. I had new wheels and tyres on order so decided to wait. No change with new wheels and tyres. Took it back to ARB who had it 3 days and they put it down to heavy spot in rim and tyre lined up = dodgy balance. Was better but not fixed. Car now has 26K kms on it and I am pulling the shims out this weekend.
As for why would Nissan fit the shims if they weren't needed, my thoughts are that is makes the steering lighter and easier for the Mum's to get into the tight car parks at soccer practice....

[Jimbo]

I took my 33" BF mud terrains off the other day and put the factory alloys back on. Shimmy is now gone but i still get a bit of pedal shudder under brakes!!

Does this mean my disks are warped??? They were only changed 5k ago :(

Can the warp be machined out of them???

Thanks


Jimmy

[ats4x4dotcom]

the change in castor/diff angle can change under braking force, making the wobble appear when braking.

[fatassgq]

Totally agree with ats4x4 on the braking account.

Also a lot of guys come to us with small lifts ie 3" when originally done and they have 2 or 3 degree castor bushes fitted. Not only do these flog out quickly (in itself causing wheel wobble) but once the suspension sags it is often a case of too much positive castor. This is made worse under braking as the front comes down. Bushes don't last forever like some of our customers seem to wish!!! I always laugh when guys say "but the bushes have only been in for a couple of years" A couple of months is enough to fuck a radius arm bush in some cases.

You should not have to remove the shims that is bullshit. It may work but it is not the prob.

The bigger the tyre you run the less castor you seem to need also. So take this into account.

Don't just take someones word on what lift your truck has. Measure the front bumpstop height and make sure. It is so important to making a decision on what if any castor correction you need.

Too much positive castor in the front of GU's GQ's is the enemy in a lot of cases.

Cheers
Brian

[Beefcake]

I'm not being a smart arse, just trying to understand, but why are you certain it can't be the shims? Are the Nissans like toyota's where you get a shim pack and set the preload using the correct combination of shims with varying thickness, or are they all installed with the same thickness shims from factory? If removing shims fixes it, how can that be wrong, if it was something else wouldn't the problem still be there?
I am pulling mine out this weekend to try it, I only have to hit 80-90km/h once and I'll know. If no better I will put them back in, and probably look at castor angle. The fact it's done it from brand new eliminates worn bushes for me, for the time being anyway.

Again I'm not being a dick and trying to disprove or question anyone, I am just trying to solve it because I'm sick to death of putting up with it.

Cheers

[ats4x4dotcom]

shims would only be a band aid until pre load loosened up anyway, its all in the alignment, and the steering damper, we even fix them for the dealers, as it saves them fitting series 2 front arms and bushes etc to series one, to try and cure it.

As well as the pull left problem thay have.....

[liftkit8]

check your kingpin bearins in the top and the bottom of the knuckle try removing the 4x 14mm bolts pop out the top one and remove the shim in there i find this helps them a bit

it works.
ive been in the automotive game (pithole) for 12 yrs. i dont do allignments / tyres or the like ,but the pissy thin ass shims are there for a reason. they put 2 in from std factory. they are there to be removed. because i tell everyone , it made an allmighty difference to the way my 4b wheeled. why do nissan install 2 shims from day dot , they know there is going to be a need for adjustment.

[liftkit8]

by the way , im running 8" lift , drop arms , 35s , and the removal of the 2 x shims makes big diff, takes all the play out, pleasure to drive again if you like driving trucks.
stacka

[trollism]

iv been trying to solve this problem ever since i got my gu and even though i have the wheels balanced so many times gues what the problem was, wheel balance when i fitted 35s i had already had a shimmy which started at around 70ks with 33s but the 35s made it much worse and obviously i put it down to the shimmy being amplified by a larger diameter tyre now these were brand new just fitted and balanced and i took it for granted that they were balanced correctly i did some off roading drove home tokk the wheels off until last night i put them back on in a different configeration and i could bearly drive the thing so the sarve i had them balanced again at my local tyre shop and i said they have to be perfect and i stood with him to make sure they were set at 0, 2 of my tyres were out by 500g thats right bloody half a kilo just 5g on the front of a patrol will make it shimmy anyway after a whole lot of stuffing round that was my problem all along even with the 33s balanced only 2 weeks ago somewhwre else i probably shouldn't mention where i got my tyres from there very well known and fit much bigger 4wd tyres than 35s and i just assumed.

[trollism]

removing shims dose work but loads up your bearings much more and when they flog out you will know about it they will seize up real well. just a thought for ya trust me and get your wheel balance done right every trye shop seems to think that near enough is good enough and it is in most cases but not ours coil front sitting nice and high it dose not take much at all.

[JeSTeROCK]

Its amazing how many things affect the nissan "shimmy"!

Causes:

1) Lifting suspension - caster, panhard & steering angles, force on swivel bearings, less effectiveness of steering dampener, radius arm chassis bush load

2) Wider, taller & offest wheels + tyres - force on swivel bearings, less effectiveness of steering dampener....tyre balance becomes vital to lateral forces, camber

3) Worn parts - Panhard bushes, radius arm axle and chassis bushes, swivel bearings, wheel bearings, loose hub nuts (technical term anyone ?) I'm sure there a few other worn parts that cause shimy problems


Problems and resolutions

Caster - Caster plates only correct diff rotation not true axle caster. When lifting a patrol either drop boxes to match lift or drop arms with diff rotation and extended length

Taller / wider tyres - Correct balance of tyres, correct preload on swivel bearings (remove shims, replace swivel bearings), wheel camber correction (using offest/adjustable king pins)

Panhard, steering angles (ever hit a bump on a raised patrol with big tyres ?) - panhard rod works best parallel to the diff. The best way to fix this is by welding a raised mount on the diff housing. The steering arm (drag link) works best horizontal. Raising the mount on the hub will fix this.

Other things to note-

Preload on steering box

Sexy looking lifted patrol vs functionality

Hope this helps

[Beefcake]

I've just removed my shims this morning and it is 100% better. Still get a little feedback through the steering wheel, but it is to be expected with larger tyres, lift etc. I could pick my speed by my wobbles before, nothing like that now.
Does anyone know if Nissan sell shim kits, because it is a fairly thick shim to remove. I would like to use a shim kit to set it up with a little less pre load on the bearings, but still enough to get rid of the shimmy.

[Rambo]

Beefcake, Just check again your shim packs. Sometimes they get stuck together looking like a thicker shim! I too took my shims out years ago, and yes it does slow the woobles down. Just make sure when you take the shims out that you take the same thickness out top and bottom or you will just be wearing your inner axle seal out prematurely! Also when you balance your wheels, its a good idea to have a look at the rim rotating on the balancer to see if they a running out, mine where, and they where the front ones, so I put the best looking and balanced on the front and all is now sweet, pleasurable driving! PS I'd definatley recommend changing all front-end bushs etc
(exspecially on a lifted 4WD) reguraly, it does make a difference!

[Beefcake]

Cheers Rambo, I've had another look and def. only one shim on top each side, approx .025". Only did the top ones today to see if it actually made a difference. Might check with Nissan tomorrow about shim kit so I can set top and bottom the same.