Uncontrolable front shudder

[MNBS 4x4]

Hopefully someone has came across the same problem that I am having with my '92 4.2efi GQ LWB. When driving at anything between 40 and 80kph and you hit uneven ground like a small pothole the car goes into a steering wobble frenzy that makes you have to stop or power through it which is a bit difficult at these speeds. I have had mates follow me backj from club trips and they all have told me it looks like the wheels are going to fall off.
I have a set of 34x10.5x15 simex JT2"s and also a set of 33" BFG Muddies for daily drives. It is really really bad with the simex's but just bad with the muddies.

The cars set up is as follows:

34x10.5x15 simex JT2"s on 15x8 rims
33" BFG Muddies on 15x8 rims
4" SP4 king springs (more like a 5")
Rancho 9000x 9 ways
5.5 degree castor plates (control arms have standard genuine bushes)
tough dog adjustable panhard( Front)
Custom panhard (rear)
Rancho steering damper
2" body lift

Both sets of tyres have been balanced and balanced and balanced more times than i care to think about.
Also the last wheel alighnment told me that it has +4 degree of castor which I was told was good for my setup.

New Panhard bushes and OME damper are my next steps although the bushes aren't that old.

ANY OTHER SUGGESTIONS PLEASE!!!

MNBS 4X4

[ron]

hi

my mate had the same problem with his.
it had something to do with the stabilising bars, i think?
he works shiftwork, so when i can get him tomorrow i will post you what he found what was wrong with his

thanks

ron

[blackmav]

ask jesus to help or read the bible

[Woop]

There are a few things that can cause this but you 'may' have too much +ve caster. 5.5 deg sounds a lot for a 4in lift. Have a shop check the amount of caster you have now with the caster plates. I THINK the ideal amount is +2 to 3 deg.

Nick

[Cheezy4x4]

1.3 degrees per 1" of lift is so close it isnt funny. Check panhard bushes ect but at that lift it will be the angle of the panhard that is the prob. We change the angle (flatten out) the panhard and also the steering arm as they should be the same give or take a few degrees. This should fix the probs you have as long as your bushes, wheel bearings and wheel balance are all good.

[fatassgq]

Hey Cheesy,
Do you lower the top mount on the panhard or bring the bottom mount up to flatten em out???

Cheers
Brian

Incidently... I saw a very highly lifted short wheel base patrol on the gateway motorway this morning and you could actually see the wheels flopping around in a big way as he went round a slight bend 100+ km/h. FUCK it looks scary. Not sure how people put up with that it must flog shit out of the front end also!!!

[ron]

hi

drop arms were fixed before the problem stopped.
they straightened them and dropped them down.

mine used to get that bad i had to stop to gret rid of the shutter

thas all he told me

ron

[Cheezy4x4]

On the panhard I do a bit of both as if you move only the chassis end it may touch the pumpkin at full up travel.

[Camshaft1]

I'd say the nissan guru cheezy probably is correct with his castor but try a new steering stabilizer and or trailing arm bushes. Had simmilar problems and a new set of trailing arm bushes did the trick.

[MNBS 4x4]

Thankyou to everyone for the advice. Cheezy, when you say to flatten out the panhard do you make a drop down bracket or is there more to it than that.

[Happy bloke]

I had the same problem on mine specialy when i went over rail crossings,i actualy had to stop and then go again .
i changed my steering damper and it fixed that problem..........
good luck.........

[Robbo]

My panard bushers only last 3 or 4 comps then out with em cos of same wiggle, new one's always stop it. I have 5" lift 7 deg caster plates big balls panards koni shocks OME steer shock(mount on chassis).

[tanky]

Hi,
Was just reading the message board after a long time and came accross this post. Was having the same problem, started after fitting the RTC steering dumper. Changed everything, including swapping the caster plates for the new radius arms from snake racing. Got better I can still feel it around 65km/h. I gave up. I have spend fortune to fix it. I could have lockers and other staf for that money.

[Shorty40]

My GQ is absolutely bog stock and it does this also

Say I am going around a right hand bend at a reasonable pace and I hit a rough bit of 'patched' pot holes.......... the front end goes beserk Shakes and shudders really bad and feels as though the front end is 'hopping' I have to back right off to bring it back under control.

It is not a one off thing either. I have turned around and tried to mimic the circumstances in which it occurred and found that I encountered the same outcome

Any ideas ?

The reason I brought this up is that MNBS 4x4 encountered a similar issue but with a modified 4b. BTW my GQ is the same model as his '92 4.2efi GQ LWB.

[tanky]

I don't think anyone knows what is wrong. Nick Mannelli had my GU in his hands and as I wrote before, I have changed everythink, new drag link, new busches, new wheel bearings, no caster plates but snake racing dropped radius arms and still have that problem. But I have to say it was much worse before, now I can at least drive it on highway. I have asked in few 4WD shops and nobody knew what to do. There was an idea to lower one end of the panhard rod to make it parallel with the tie rod (I hope I got it right). It would interesting to know if it really works and how it is done.

[GUDATTO]

I have a 99 GU with the same problem and would like to know how you lower the chasis end of your panhard rod.
And can someone explain why this should fix the prob?

[Area54]

Many people have been down the same road as Tanky (metaphorically speaking) in so much as changing everthing over and over again. Had the shimmy in the mav a few years back, but changed to 15x8 alloy and the problem disappeared. I also had a shimmy with my JT2s, but this was because the rims are trail abused. I know this may not help you, but at least you know you are not alone.

[hypo]

i had the same prob wif the GQ axles i put under my lux, i couldnt drive it above 20 k's. but i lowered the tyre pressure 2 18PSi and it was all good..

i have since fitted some wedges (i put leaves up front) 2 bring the castor back 2 somewhere near normal and its fine now. probly drive better than it did wen std..

so maybe u guys need 2 check the castor maybe the castor plates r not right ?? cant member who tole me but the best castor setting is between 0 and 2 degress layin back if that make sence ?? basicaly the front of the swivel bearing plate is higher than the rear..

[Robbo]

Bloody hell shorty 40 I have never heard it happening in a stock vehicle before, that indicates to me that its not so much the mods but ware & tare on the front end. When modified all the weak points realy start to show, ie;panard bushes,cv & wheel brg adjustment,wheel bal,old steer shock,play in steer box,cruiser offset on nissans & 4 tie rod ends.
Andrew at on track has got some nissan bushes for my big balls panard rod so will try them next. One things for sure the bigger diametre tyres we us the worse it gets, fit the old outa balance 33's back on & its gone.(also looks poxy).

[CJ Burns Esq]

Tanky, thats a shame you are still having problems. If you remeber we spoke at mannellis a couple of months ago. I'm still having issues with mine. 4" spring lift and 3deg bushes and the vehicle dives to the left under brakes and the steering usually pulls to the left unless you hit a bump and it may go right. Been back a couple of times and had more wheel alignments (complete with lots of differing expert advice) than I care to remember and still no joy.
As someone suggested earlier, make sure the basics are all fine eg bushes etc before chucking steering stabilisers etc at it.
CJ

[Fathillbilly]

i would be checking:

Swivel hub bearings
Panard rod bushes
Radius arm bushes
Steering dampener

Stu

[JBE]

My truck had the wobbles after I picked it up from the tyre shop (brand new Cooper STTs on my Roh steel rims). On one downhill section of the road at at speed of around 80 km the front started to shake violently and I had to pull over. I noticed that one rim on the front had around 340g balancing weights put on. I got the tires rotated and rebalanced at another tyre shop (Mark & Wallings in Ryde). These guys did an excellent job and the problem is gone on my truck. Tyre balancing seems to require a lot of experience to get it right. As I could directly compare a good and a really pathetic balancing job, I think that this might be a major factor contributing to this problem. This would also explain why some people couldn't fix the problem after virtually swapping everything on the front end. Of course, worn bushes can make such a problem much worse and should be checked as well.

[MNBS 4x4]

Thanks again for all the recent replys, going to start swapping bits and pieces with spare parts my mate has. fingers crossed it is fixable.


MNBS4x4

[hypo]

My truck had the wobbles after I picked it up from the tyre shop (brand new Cooper STTs on my Roh steel rims). On one downhill section of the road at at speed of around 80 km the front started to shake violently and I had to pull over. I noticed that one rim on the front had around 340g balancing weights put on. I got the tires rotated and rebalanced at another tyre shop (Mark & Wallings in Ryde). These guys did an excellent job and the problem is gone on my truck. Tyre balancing seems to require a lot of experience to get it right. As I could directly compare a good and a really pathetic balancing job, I think that this might be a major factor contributing to this problem. This would also explain why some people couldn't fix the problem after virtually swapping everything on the front end. Of course, worn bushes can make such a problem much worse and should be checked as well.

good point i run 37" MTR's that hevent been balanced so mayb i should try this

[TUFFRANGIE]

i put my mates 31's with 15x7 rims on mine (usually 15x8 33's with big offset) and it stopped the shudder, try some standard tyres on rims with standard offset and it may narrow the problem down to the wheels or offset of the rims exagerating the problem

[dumbdunce]

Bloody hell shorty 40 I have never heard it happening in a stock vehicle before...

really? this is such a common and well known problem, and it happens even on brand new vehicles. I have heard from a reliable source that when ford was selling Mavs, several customers actually got their money back because ford and nissan could not solve their front end vibration problems from day one. If you have ever tried to sell a car back to the dealership at sticker price you know how remarkable this is. I have seen it in a week-old GU, so it cannot be said that the problem is caused by worn components.

it happens on 80 series and bunderas too. the solution almost always involves getting the castor right (and 'right' can be different in different vehicles), combined with good wheel balance and tight suspension joints.

[J Top]

Positive castor improves straight line stability,so running more castor can
improve this problem.
The negative aspect of more castor is heavier steering.
With power steering 0-2 degrees is a joke,I would be looking at
5 degrees +.
In your shoes I would also be spending my money with someone who has
enough experiance to guarantee their repair,maybe Cheezy
J Top

[big red]

i have a seven inch lift and used to get the wobbles with 35's on standard offset rims.
wider rims, bigger tyres, big offset rims all made it much much worse.
fixed mine by fitting drop brackets.
still get wobbles when the 38's on 10" rims are way out of balance [lost weights]
also get wobbles when running 40 mm offset beadlox with 36 swampers which are not balanced at all but the 35's are now out of balance and don't wobble.
Also get wobbles when panhard bushes are worn out.

Nissans seem to be right on the edge of wobbling in stock form and any little thing that is slightly wrong pushes them over the edge

It seems like most people go to a lot of trouble to fix the symptoms but no one tries to fix the cause.

IMHO the cause is the angle from horizontal taken between the chassis pivot point where the radius arm pin is mounted and the pivot point on the diff where the radius arm bush is mounted.
The snake drop arms still have the same angle as a standard arm with the same lift so they still wobble.

flatten out the radius arms with drop brackets and lose the wobble

BUT, if there is something else wrong you will still get a wobble

[coke]

I must be one of the liucky ones.

I had a severe fear of this after a mate lifted his truck similar amounts to mine 18 months ago. As you all know I did my car recently, and after some different issues, the thing drives better than when i bought it.

It has 7 degree castor plates, about a 7" lift, 2" bbody lift and runs 33 MTRs on 15x8 ROH steel rims.

I couldn't be happier. It also had a stock NISSAN steering damper...

Andrew

[Robbo]

Geez coke I reckon if I lifted mine another inch it wouldn't be drivable, your one of the lucky one's.