Offroad-Express

We have replaced bushes in the suspension, steering damper, put in new springs, shocks, new universals, balance drive shafts, checked flanges on diff & gear box, checked wheels for running true, checked king pin bearings, wheel bearings. When tyres replaced the vibration goes away but soon returns when tyres wear down by about 1/4. The vibration is getting quite bad. Can anyone offer a suggestion please of something we haven't already tried.
Many thanks "Stumped"

Try going to a different palce to get the wheels balenced.

There are some places that have no idea how to distribute the weights properly on the wheel and to use their balencing machine properly, and on the big wheels we all like to run an out of balence wheel can be very pronounced through the steering.

That would be my first place to check.

That and what sort of pressure are you running your tyres at??

Give us some idea of how the vibration feels, is it a regular pulsing vibration??

Is it just vibration as if you can feel every little stone on the road??

That would help alot!!!!

Just a thought, but isn't this common on a GQ with raised (new) springs?

This is, of course, assuming the new springs were raised ones and your GQ is a shorty... and, in fact, a GQ...

Gearbox packers, raised engine mounts... the usual fixes?

Also, something noticable on lighter trucks is the out-of-balance shimmy on tyres is not so noticable on big-ass tyres when they are new because of their weight... they tend to hop up and down (less noticable, believe it or not) rather than shimmy... until they wear down a bit and loose some of their mass. As suggested - get your wheels balanced somewhere new... and have them check the balance before they pull the weights off...

Steve

Sorry I didn't mention the vehicle is a 1992 Safari Granroad LWB. Tyre pressure is 40lbs. We've done the balance thing with several tyre specialists so that would not appear to be the problem and we've tried FIVE new sets of tyres. The vibration comes through the floor even with new tyres when it's barely noticeable. With half worn tyres it comes through the floor and the steering wheel. It happens cornering in either direction and can happen on a long straight. At the stated speeds it is a regular judder, but not pulsing. It's not like you could feel every stone on the road, it's more like a castor vibration which was the reason for fitting the new springs. Gearbox and engine mounts checked.
Any further suggestions would be most welcome.
Many thanks, "Stumped"

Sounds to me like drive line vibration then.

Its shows its self in all sorts of funny ways, on mine, i can feel it through the clutch pedal when changing down gears of all things

Can you check for me that you front hubs are diss-engaged properly??

Try pulling the rear prop shaft off and take it for a spin in 4x4 (FWD) and see if the vibrations still there. (Its a 10 minute job).

If your front hubs are out, that will rule out vibration front the front shaft as it will not be rotating.

By removing the rear shaft and driving on the front diff, you can rule out that one as well.

Check the left hand engine mount.

Its not a warped disc rotor is it??

My bet is mis-aligned UJ's.


Edit:
If you have the auto hubs check that the bolt in the center isn't turned to manual and they aren't permanantly locked all the time.

If they're behind hub caps how would you know?? (apart from seeing the D/S turn when you have a front wheel jacKed of the ground)

Could even with the bolt turned to auto, the hubs might not be diss-engaging properly.

If they are locked, then the vibration could well be coming from the front D/S.

Not through the D/S being out of balance, as you've had it balenced, but through the angles of the universals having a greater than 3degrees difference in angle to each other.

This can happen from coils that increase the ride height as little as 50mm.

Something else to have a quick look at anyway, its all totally irrelevant if the hubs are working properly and the front D/S is doing nothing when in 2wd.


Did you get the rear universals set up and shimmed/spaced/centered properly??

There was a case in OZ were a guy went all out trying to get rid of a vibration and after spending huge $$ found that the shop that had replaced the UJs hadn't set them up properly after all, and it was the cause of his problems.

DB got nailed... but you said you replaced the UJ's :scratch:

Here's a couple of longshots to look at...
Wheel bearing... I've heard of them cousing a vibration without the noise, easy checked jack each wheel and spin by hand you'll hear a quite rumble, don't think its this as you've done 5 sets of tires the bearing should have died by now...

The only other thing that makes sense (to me :geek: ) is a bent axle flange or rim... a new tire is nice and round and works sweet but as the tire wears it will wear harder in certain areas due to the wobble this would put the wheel out of true and give you your shudder.... but I would have thought the tire companys that did you allignment would (should!!) have found this one Easy to find look at your old tires the wear will be uneven

Need more info
Is the vibration speed controled ... faster you go faster the vibration
Does the vibration change, stop when you:
Turn
Push the clutch in
Brake
Accellerate
Is there any noise with it ??

Cheers Reece

We had the same issue with our 1990 LWB Safari.

Tried a new streering damper, rebalancing the tyres, swopping the tyres around (at 2 different shops). Had several garages give the front steering/suspension a once over, all said there was no problem and all the bushes were fine.

Finally told garage to pull panhard rod off and physically check bushes, with the rod off it was found that the bush has worn clear through, allowing the entire front axle to move in a sideways motion. Replaced the bush and have had no futher problems with shimmy'ing.

Hope this helps.

Read the first post thoroughly, you will see he has been very thorough and all you mention has already been done.

Stumped wrote:We have replaced all bushes in the suspension, steering damper, put in new springs, shocks, new universals, balance drive shafts, checked flanges on diff & gear box, checked wheels for running true, checked king pin bearings, wheel bearings. When tyres replaced the vibration goes away but soon returns when tyres wear down by about 1/4. The vibration is getting quite bad. Can anyone offer a suggestion please of something we haven't already tried.
Many thanks "Stumped"

He hasn't missed anything.

So looking out side the square, eliminate the driveline from being the culpret as that has been over looked so far.

I know that when i have my hubs engaged on the road, awith the front drive line being all out of allinement these days, i get a nice massage on the steering wheel at those sort of speeds.

Ok - we have balanced and replaced universals but the old ones were perfect when we took them out. Replaced bushes in front and rear suspension. Replaced bushes in panhard rod. Checked flanges and wheels. Vibration doesn't change with speed, when clutch is pushed in, on braking or accelerating. There's no noise other than things falling off. The passenger seat shudders when it's really bad.
Keep the suggestions coming - we need to get to the bottom of this. Many thanks for your input so far

Just a left field comment but when I had the UJ's replaced on my hilux's rear shaft they reassembled the shaft 90 degrees out and induced a vibration that could be felt when changing gear and driving. The mechanic didnt do that to yours also?

Heath

What about the body mount or front suspension mount under the passenger side seat? Dad's makes a clunk everynow and again from there.

Heath

It really does sound like wheel shimmy.

Back soon, i gonna ask some questions......................................

Thats funny. Mine does same thing at same speeds as well, 85-90kph. LWB 91. I have no lifts or any mods to steering or suspension or anything, they possibly did a poor job on the new tyres but it very much comes and goes, always the same speed though 85-90. Someitmes its not there for like days and then it will be for a while and then not.

I know this doesnt help but seemed an interesting coincidence.

Hey just had a thought, is the vibration there if you change gear... do you get the vib at that speed in 4th and 5th??

Cheers Reece

Hey stumped, have you fixed your 80 to 90 vibration yet, if so what did you do to fix it as I am aware of a few other shortys with the same problem. We beleive its torque related

Be great to hear where you are at now

Sorry have been off air for a few days had a wee mishap followed by a trip to A & E - ok now
In reply to Heath - doesn't clunk
In reply to ChaffNZ & Warhog - When we find the answer we'll certainly let you know
In reply to De-Ranged - 4th & 5th (2WD & 4WD)
In reply to Dieselboy - The vibration is so bad that the drivers fingers go numb after driving for 15-30 mins. The UJ's were fitted before the driveshaft was balanced so the problem should have shown up when the shaft was balanced. We have also checked the free wheeling hubs are disengaging properly. Just to be sure we will take the drive shaft off and try that again. Did you have some questions?

Just another thought, have you tried taking the rear driveshaft off and going for a run to see if this vibration is there. Obviously you will need to engage 4wd so the front driveshaft is the one moving the Nissan.

In reply to Worthog - it's a LWB. We've tried taking the driveshaft off and running it in 4WD before we got the shaft balanced. We'll try it again shortly. Will keep in touch