98 110 violent front end shake - harmonic

[uninformed]

Hey all,

I was heading up to Toowoomba from the Gold Coast. At Plainland (just before the Home Hardware) I drove over a very small step down in road surface. Think something along the lines of a resurface and where they blend the new and existing. So quite a small step down straight across my lane. I was doing 95-100, maintaing speed (i.e. not braking, not decelerating or accelerating) Slight decline in road and nice straight road. This step down minor and considering the amount of road works, pot holes and defects from Ipswich to Toowomba, very minor.

Well the front end started an immediate shake that came through the steering wheel and nearly shook me to death. I mean I could feel my brain bouncing in my skull. Very, VERY disconcerting. This was so bad I could barely hold the wheel with both hands and try to keep some sort of line, which was for the shoulder and into a short turing lane. It did not stop until I got down to about 30km or less.

I pulled up in this side road and looked over the vehicle. I am surprised it did not tear the 110 apart it was that bad. Everything seemed ok???

I have had similar happen once before, at 80km/h on the end of Bermuda St about to go onto the MWY at Burleigh. I was on a slight up hill, left hand bend and decelerating. I put it down to a fluke in combination with the crappy concrete road surface that puts my 110 into a pitchy harmonic of front and rear suspension.

This time was worse and pretty ok road all things considered.

I had just done a tyre rotation.

A month ago, I overhauled the front axle: new wheel bearings, swivel bearings etc.

Last week I had my mate check the wheel alignment: Castor is at -0.5 degree. each side is within 0.25 degree of each other. Toe was spot on according to him.

New OEM steering box in the last 12 months with new panhard bushes. I took care in getting all things correct as per manual (steering box centred etc) It drove spot on.

I could possibly have a very small shimmy at 100km/h, but it is VERY small if it is there?

The steering, post event, is now trying to veer right, steering wheel seems off centre. Im guessing steering dampener???

Steering dampener is 5 years old or so, Bilstein.

Wheel bearings feel good. Hubs are not hot at all.

Drag link and track rod are Maxidrive.

What to look for...I do not want to die or kill someone!!!!

[blue_mini]

Haven't lost a wheel weight have you?

[uninformed]

Haven't lost a wheel weight have you?

It doesnt look like it. As soon as I can, Ill take it to my mate to check wheels for balance.

For reference, they are: LR 130 steel rims, with Goodyear MTR 235/85R16

[djam1]

Loose swivel pins??

[uninformed]

Loose swivel pins??

When I jacked the wheels up to check wheel bearings I would have thought that I felt it then if so???

[Jock The Rock]

Will be following this with interest

I had the same problem with my County when I brought it home from WA. 100km/h and bam it would start up, scared the bageezers out of me the first time. I found it was possible to accelerate out of it

When I stripped it all down for the rebuild I couldn't find anything obviously wrong with it.

My old man's 130 is now doing the same thing, I've been tasked to fix it.

Firstly I'm planning on a new set of tyres as the old ones are knackered, then tie rod ends and possibly tierod as the old one has been bent once or twice, wheel alignment, then steering damper, possibly front shockies if that doesn't fix it I'll get serious with it

I remember once reading about this issue having something to do with a lack of swivel preload. His now has just over 200,000kms on it, so I'm thinking a strip down, CV clean and reshim of the swivel bearings may be in order

Will be good to hear other peoples experiences, and will keep you posted on how I go with my own repairs

[weeds]

If your steering wheel is off centre than you could have a bent steering arm

How are your radius arm bushes??

[djam1]

Serg
If they don't have sufficient preload then you wouldn't feel it because of the steering box and damper.
Don't want to send you on a wild goose chase but I found i could make my stage 1 better by pulling a shim or 2 out.

I originally said loose but I meant lack of preload

When I jacked the wheels up to check wheel bearings I would have thought that I felt it then if so???

[uninformed]

If your steering wheel is off centre than you could have a bent steering arm

How are your radius arm bushes??

Ill check in the am (do you mean link or the arm part of the case swivel housing?)

RA bushes should be ok, had new rubber at axle and Super Pro at chassis done about 2 years ago. what is the best way to check these?

[uninformed]

Serg
If they don't have sufficient preload then you wouldn't feel it because of the steering box and damper.
Don't want to send you on a wild goose chase but I found i could make my stage 1 better by pulling a shim or 2 out.

I originally said loose but I meant lack of preload

I can only go by what the WSM told me. New bearings are NSK, old ones were Timken (and seemed fine). I checked the preload with a trigger pull gauge (rifle) over and over and got a consistant reading in the mid range of LR specs. One side used exactly the same shim stack as previous, the other only needed a slight adjustment)

I can check again, it just means removing the: wheels, brakes, drag link and track bar (I think?)