[royce]

want33s wrote:

If it is shaking/shimmying/wobbling AND not centreing itself after a turn I guarantee it is a caster issue.

castor gets blamed for heaps of stuff cause people dont understand what they cant see

more shaking is caused by toe than castor

more shimmying is caused by too much positve camber than toe

I had the problem Saam describes, did about 20 alignments on it I reckon, 0.5mm of toe at a time and stock, heaps and less castor and made no difference

I have typed the cause out before and its long winded, its got heaps to do with harmonics and hitting the perfect point that the front wants to shake and builds energy at teh same time, its the same thing makes extractors work and subwoofers hit harder in a certain spot

[Saam]

I'm glad i do have a damper here to chuck on as well, all i need to do is make up a second bracket suited for mounting onto the panhard.

The toe on my car is fine Ive been through it a few times. Ive been reading up on castor and how it works with dad, the problems that i had before i swapped to the rubber bushes themselves are worth solving and i beleive they are castor related. Measuring it at the moment it has much less than 7 deg..

[want33s]

royce wrote:

want33s wrote:

If it is shaking/shimmying/wobbling AND not centreing itself after a turn I guarantee it is a caster issue.

castor gets blamed for heaps of stuff cause people dont understand what they cant see

more shaking is caused by toe than castor

more shimmying is caused by too much positve camber than toe

I had the problem Saam describes, did about 20 alignments on it I reckon, 0.5mm of toe at a time and stock, heaps and less castor and made no difference

I have done enough wheel alignments to know that camber has absolutely nothing to do with shimmying/wobbling.... Pulling and darting/diving possibly..

Lots of old cars with solid axles EG anything pre 1940 had positive camber IE : wheels further apart at top than bottom... and they drive just fine..
If you have enough caster the kingpin inclination will make the wheel want to go straight ahead or turn toward centre of car.... If both wheels want to turn towards centre of car it will drive straight and will self centre.

Why is it that only 4wd's have steering dampers ?? Trucks are solid axle and don't use them... Older cars don't either..
They are there to cover up the effects of bad alignment settings or worn parts.

[Saam]

Today i fitted the steering damper just to try and make it safe to get out to dads work tomorrow, it has reduced/stopped the really bad effects of the wobble but you can still feel when it happens and what not, so we are working out what we need to do tonight and taking it out to his work tomorrow to change the castor.

I mounted the damper from the drag link to pan hard rod, modified one of the original kit brackets, seems to clear everything

[atari4x4]

set fire to the whole lot, fire fixes everything!

[Saam]

lol i have come pretty close a few times, but i am so close to getting it right i'm actually feeling alright about it this time, if it doesn't work i may go the fire technique

[Saam]

WELL castor is now at 7 degrees and i have a steering damper fitted AND i still get the problem..not as frequently but still as bad when it happens WHAT THE FUCK DO I DO NOW lol

[atari4x4]

that seems like heaps of caster, check your wheels to see if you have lost any wheel weights?

or just set fire to the front end & install some IFS

[Saam]

ifs would be more annoying lol, also i have had two sets of wheels on it, it is much more severe than out of balance wheels could produce

[royce]

do they really have that much castor standard?

[Saam]

i dunnooo anymore, it was at like 2-3 at the start, we tried it at 4.5 and it was still happening so we moved it to 7, decided to leave it there, can be re drilled later because we did the adjustment in the diff brackets rather than changing the control arms so it's easy if i need to move it back, it drives nice just still does the murder wobbles...

[Saam]

i came across the 7 deg figure from reading a whole heap of stuff on the internet and then want33's and what dad had found aswell, it does not seem to be changing the issue though, so not sure what the next move should be, the steering damper definitely stopped it sometimes but it still managed to get bad enough to take over/

[Saam]

"Sustained oscillation has two necessary components: An underdamped second order or higher system and a positive feedback mechanism. An example of an underdamped second order system is a spring and mass system where the mass can bob up and down (oscillate) when hanging from a spring."

this quote makes me think it could be my stuffed shock absorber...

[Saam]

but then that also makes no sense

[royce]

pull 1 rubber bush from each control arm and replace with urethane, the bushes are your springs in that quote

OR stiffer panhard and mounts

[Saam]

hmm how would i stiffen the panhard ?

it has poly bushes in it, i will have to check that out ..

[royce]

the control arms are rubber now arent they?

panhard I dunno, the only way I can see it shake without the steering wheel moving heaps is by the diff swinging side to side

[Saam]

the steering wheel still moves heaps, the panhard is as solid as a rock, and yes the control arm one are rubber again, because it used to be 6000 times to stiff.

[kenn]

Have you adjusted your toe in. This happened on my jimny years ago when i lifted it , toe in 2deg fixed my problem. Fingers crossed .

[want33s]

Take it in for an alignment Sam.. Find out what the settings are now AND what they are supposed to be..

[BenT]

Saam wrote:

WHAT THE FUCK DO I DO NOW lol

Have you checked the felt & rubber seals on your knuckles? These play a big part in damping the steering system. In one of your pics the knuckle seals look pretty rooted (and most likely your kingpin bearings).

I've fixed death wobbles before by just tightening the 6mm bolts that hold the seals in place...

And here's a quote direct from the Suzuki Factory Service manual:

Suzuki Factory Service Manual wrote:

Steering Knuckle Oil Seal
The oil seal used at the spherical sliding joint
between the knuckle and the inner case accomplishes
the additional purposes of keeping out
road dust and of acting as the damper for the
steering handwheel. As the wear of this seal
advances, its damping effect decreases and thus
make the front wheel develop a tendency to
“shimmy” not only that road dust begins to
creep into the sliding clearance to promote the
wear of the spherical sliding surfaces."

Ben

[Saam]

thanks ben another thing to check !!!!

king pins are fine, had it on the hoist checking today, passenger wheel bearing adjusted, i have ordered my new shocks, a new tire rod end (tiny but of play) and i also found a perfectly good steering shaft uni to put in.

I will definitely check the wiper seals and tighten them up ! and get an alignment if it is still there

and kenn i did play with toe..

anyways here is what all the trouble has been for (new shocks alow for all this travel )))))) Remember i have no body lift




also the roll stiffness is feeling very stable, rear is limited by bushes and compressed shock length, but i am happy with the higher roll stiffness that provides.

sam

[kenn]

Ace...

[Saam]

tightened up the wipers and put new tie rod end in, no difference lol by the time i find it the sierra is going to be brand new.

steering shaft uni and shocks hopefully in this afternoon depending on if the shocks show up

[2stroker]

Royce was mentioning that it could be harmonics and that it is a complex issue that can cause dramatic problems at different speeds. I think that he is right, champ after just reading through the 6 pages of this post you have tried everything else so take those fabricated front arms out and put the standard one back in and see if they are the problem. I know it is a lot of work but it is worth it rather than crashing your vehicle. It appears that the problem was exasperated when you put rubber bushes in the fabricated arms so the arms themselves could well be the problem, as Royce said harmonics are a strange thing. I would be looking at some strengthening or bracing along the length of the arm to ensure that they are not flexing and creating an unwanted harmonic vibration. I would be stiffening the tube on the front arms by welding something like a length of 10mm by 40mm flat on it's edge along the top of the tube. You could stitch it in at the diff end and taper it at the chassis end.

BenT thanks for quoting that for us re the rubber and felt wipers, I know someone who laughed at the suggestion of it affecting steering dampening when talking about a similar topic some time back, I printed it off to give to him.

[royce]

I reckon even changing the weight of the arms or diff could remove it, try strapping some bricks the the arms

not joking either, ever seen the massive rubber blocks bolted the the front arms of some 4wd's?

[shep]

my bitsashitty has a 3kg block of rubber hanging of the back of the transfer. i recon royce might be onto it.

[Saam]

the arms are made out of 10mm wall hollow bar, they are twice as heavy as the standard arms i would say i can't see them twisting at all, also the standard arms do not work with this amount of lift at all, and they are stuffed lol.

I managed to get rid of it yesterday though, tightened hub wipers, new outer tie rod end, new steering shaft uni joint and i read a few things about toe out being a solution, so i adjusted the toe out and it drives great, obviously a little heavier in the steering and i am going to keep an eye on tyre wear but it seems like with the combination of what i have done it's not doing it any more. I think if i took the steering damper off it might, but i have done alot of driving on all sorts of roads since i did it yesterday and it is not happening so fingers crossed.

The coilies have a big rubber block bolted to the rear diff and the transfer case

The thing that makes me think it was not the arms is the fact that it used to do it when it was all factory then went away until i put the rubber bushes back in, but they seem in good condition, if the problem starts up again i will be getting some new rubber bushes sent over from japan or the uk where they have rubber ones available to buy.