Thread: 98 110 violent front end shake - harmonic

managed to get the axle end of RAs changed today and installed the Super Pro bushes I had in my cupboard. The OEM type bushes that came out looked ok and the crush tube concentric in the bush. Ill be doing a few KMs tomorrow so will get to see any differences.

I will be fitting new springs in about 3 weeks so will get the shocks out and give them a good going over along with new bushes.

One thing that may have hindered me during the setting of swivel bearing pre-load, I can not fit my CVs in after. I have to have them go in with the swivel housing. I remember having to hold/guide the CV stub shaft as I pulled the spring gauge on the swivel. It was a little awkward, but I did each side at least 10 pulls to make sure. Maybe it did or did not have an affect??

Originally Posted by uninformed

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One thing that may have hindered me during the setting of swivel bearing pre-load, I can not fit my CVs in after. I have to have them go in with the swivel housing. I remember having to hold/guide the CV stub shaft as I pulled the spring gauge on the swivel. It was a little awkward, but I did each side at least 10 pulls to make sure. Maybe it did or did not have an affect??

What values did you set the preload to? With or without oil seal fitted?

Have you measures the wheelbase (hub centres) each side?

I have the exact problem, with all that you have done to fix it & more.
It was almost eliminated but came back with a vengeance when I swapped to a particular set of tyres that I'm trying to wear out.
I think I'll buy new tyres as the next tactic.
Really scary stuff though, I have to keep in the left lane !! One thing that is in the back of my mind is that the County did have a "minor" rollover as I bought it as a wreck, but it would be bad all the time if that were due to some mis alignment. Funnily it gives no trouble at all on 34" swampers.
Following this threads with interest

Originally Posted by DeeJay

I have the exact problem, with all that you have done to fix it & more.
It was almost eliminated but came back with a vengeance when I swapped to a particular set of tyres that I'm trying to wear out.
I think I'll buy new tyres as the next tactic. ------ Funnily it gives no trouble at all on 34" swampers.

Originally Posted by wrinklearthur

------ Looking next at the tyres themselves, you can have them balanced nicely, but so can a square object, are the tyres true around their circumference?

Are the wheels seating properly on the hubs? check for run-out ( using a dial-gauge indicator is a good way to do this ), --------- If there is a crook tyre that has part of it's wall flexing differently as the tyre rolls, that would be a tricky one to determine. Swap all the wheels with a known good set off another vehicle and try both vehicles, does the problem then occur on the other vehicle?

A variation in rolling radius of a size of tyre on a particular rim, could place the centre line of the tyre too close to where the swivel-pin axis line meets the road and that is probably why when changing wheels the problem seems to go away. To get around this one try your tyres on a rim with a different offset.

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Originally Posted by isuzurover

------- Have you measures the wheelbase (hub centres) each side?

Originally Posted by DeeJay

------ but it would be bad all the time if that were due to some mis alignment.

Originally Posted by wrinklearthur

------ the whole axle could be working within the flex of those bushes.
Next is the trailing arm bushes and the centre pivot on the back axle, are they firm also in their fitting? any slight movement there will cause the rear axle tracking to vary.

A bent outrigger can be a not so visible reason for misalignment. do as isuzurover has said and make a accurate measurement of the hub centres on both sides and I would go a step further with this by loading the axle housings to skew them.
Load the axles then measure the centres again and do this loading with equal pressure for both sides, the distance between the centres should be the same for both sides adding the crush or expansion of the bushes.

The camber of the road surface can cause the Land Rover to lean and that will load the axle bushes causing the axle housings to skew as well, try sitting the wheels on one side on a pair of concrete blocks, take your measurements then repeat for the other side.

If this measurement could be done on another same year / model vehicle and running similar tyres it would be interesting to compare.

I did advise someone in a thread on here some time ago, that he may had a misaligned chassis and to add a correction washer to where the trailing arm passes through the outrigger.
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Originally Posted by isuzurover

What values did you set the preload to? With or without oil seal fitted?

Have you measures the wheelbase (hub centres) each side?

approx 1.4-1.5kg, seals not fitted. (as per WSM) That value was not what was required to get the swivel moving (that is higher), but once it was moving.

Not yet but will do.

Originally Posted by wrinklearthur

A variation in rolling radius of a size of tyre on a particular rim, could place the centre line of the tyre too close to where the swivel-pin axis line meets the road and that is probably why when changing wheels the problem seems to go away. To get around this one try your tyres on a rim with a different offset.

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A bent outrigger can be a not so visible reason for misalignment. do as isuzurover has said and make a accurate measurement of the hub centres on both sides and I would go a step further with this by loading the axle housings to skew them.
Load the axles then measure the centres again and do this loading with equal pressure for both sides, the distance between the centres should be the same for both sides adding the crush or expansion of the bushes.

The camber of the road surface can cause the Land Rover to lean and that will load the axle bushes causing the axle housings to skew as well, try sitting the wheels on one side on a pair of concrete blocks, take your measurements then repeat for the other side.

If this measurement could be done on another same year / model vehicle and running similar tyres it would be interesting to compare.

I did advise someone in a thread on here some time ago, that he may had a misaligned chassis and to add a correction washer to where the trailing arm passes through the outrigger.
.

certainly all possibilites, but seems all most like the magic bullet that shot JFK. i.e a long shot.

The reason I say this, I have owned this vehicle for 14 years, this is recent. I have had no crashes, impacts etc that would cause anything to bend IMO. The worst amount of force would be the death rattle itself.

SO with that in mind, I will continue to go through the basics first. I still have to check the swivels and a few other things.

Wont get a chance today, im off to Stanthorpe.

Right hand shock absober seems good also. No signs of damage or bad bushes. Top bushes replaced. Bottoms will be done in a few weeks.

Jacked up each side and checked wheels for play (one at a time). No noticable play at all in either the vertical or horizontal planes. Any movement at the swivel resulted in the steering wheel moving. I figure if there was play in the TRE or swivel bearings it would be able to move some what before taking up the slack and moving linkage???

Wheels both spin about the same amount by hand. I.e. no difference in rolling resistance, not that I can tell anyway. I guess that can rule out a dragging brake?

Steering box and panhard mount bolts seem nice and tight.

No noticable play in the pitman arm to steering box.

Wheel base came in with in 1mm but steering was not exactly straigh ahead. Id say its pretty damn close.

Anyone want to guess how much a difference you would need in wheelbase to notice it on the road?

Originally Posted by uninformed

Wheel base came in with in 1mm but steering was not exactly straigh ahead. Id say its pretty damn close.

Anyone want to guess how much a difference you would need in wheelbase to notice it on the road?

That's amazingly close !