So I've got some front end work to do, apparently.

Vehicle:

1996 Discovery 1, +2" OME lift.

Problem:

Faint but worrisome wheel shimmy, usually hits at exactly 55 MPH. Occasionally happens even on smooth roads, can get pretty extreme if I hit frost heaves or rough pavement anywhere between 50 and 60 MPH. This is a problem because all of the roads here have frost heaves, and most of the (paved) back roads are just right for that speed range...

Background:

About three months ago I went in and got an alignment, after trying to drive through a 5' tall snowbank at 40 MPH. Hitting the snowbank didn't seem to do anything to my steering, but I wanted to have it checked out.

When I got it back from the shop the steering seemed touchy, but I stupidly justified it saying to myself that my caster angle is off anyway from the lift, they probably got the other specs right and not to worry about it. No problems for a couple months.

About one month ago I hit frost heaves and the steering wheel went crazy. That was 55 MPH, and scared the heck out of me. So I pulled the Rover into the garage and checked everything out. Most obvious problem was the Panhard rod bushings, so I replaced those. For a few days, I thought the problem was fixed. But now the same symptoms are back.

Last week I jacked up the front end again. The tie rod ends are tight as far as I can tell by hand or by prying with a screwdriver. My left wheel (driver's side) has about 1/8 to 1/4" of play in it when I hold the top and bottom and flex it back and forth. The other wheel doesn't do this. I didn't notice this before but I'm guessing the condition was already there.

I'm inclined in a redneck sort of way to replace everything in the front end, it couldn't hurt. But my wallet is screaming otherwise. So my question is, what next? What is the most economical way to proceed? I'm worried if I don't fix it soon I will chew up my tires, which I'm not planning to replace at least until fall...

I already have a set of wheel bearings lying around (two inners and two outers), and most of the necessary seals, gaskets, and washers. I may do some brake work at the front time (pads, rotors). Could the bearings cause this? Do I need to suspect swivel pins, swivel pin preload, or anything else? I'm just trying to isolate as many variables as I can, but I've honestly never worked on a solid front axle until now.

I have balanced the wheels recently, but not since the problem started.

Thanks in advance.

EDIT: I'm not sure if it is loose when rocking the wheel from side to side, I will check that later.

 

I'm hoping to order parts tonight if possible, what things do I need to check?

 

I'd worry first about whatever it is that is causing the wheel to move.... whether it be bearings or swivels pins or whatever. You'll have to fix the known bad stuff first, to eliminate it as the cause.

 

True. So how do I distinguish between bad swivel pins and bad bearings? The Rover is down for now, at least until I know what's causing the problem and have the parts on the way.

 

If it's bearings only the wheel will rock no matter where you grip it. If it's swivel pins only it will rock only if you grip it and 12 & 6. If it's both it will rock no matter where you grip it.
You do have too much play though.

You could have two light a swivel preload without the wheel rocking and get death wobble.
It could also be other suspension bushings.

Also make sure your steering box mounting bolts aren't loose.

 

So if it rocks everywhere, replace the bearings and re-check, right?
If it only rocks at 12 and 6, replace swivel pins and re-check?
Can I assume if it rocks worse at 12 and 6 but still rocks at other points I should replace both?
I'll check/retorque steering box mounts while I'm at it.
I'll visually inspect bushings as well.

If all that fails, should I default to a full set of front suspension rubbers? Or just replace them one at a time at random???

Thank you very much, I think that points me in the right direction.

 

Might as well do both if you're not sure. Since you will be in there anyway, and the cost isn't too much more. I need to do mine to make my death wobble go away. Fortunately, the highest posted speed is 50mph, so I only feel the wobble when I speed...

 

I had experienced the exact problem with my 97 disco. Upon hitting 55 mph, the death wobble would start but will stop when either I exceed the 55 or lower! The only thing I did to solve the problem ( at least in my case ) is do a swap with the tires. Front left to rear right and front right to rear left! Never again that the death wobble came back!

 

At 120k it wouldn't hurt to replace all the suspension bushings front and rear if they are original. It's a little early, but not a whole lot. Though if money is tight you can wait a while. If it's been leaking oil on to the bushings that will cause them to deteriorate faster.

If money is tights I'd plan on at least doing the hub bearings, but before replacing them, tighten the loose ones and see if that gets rid of the wobble. If it does, just replace the bearings. If it doesn't, do the swivel pins and bearings and hub bearings.

 

Yeah money is tight at the moment but things should improve in the fall when I start work again. College is sort of forcing the poverty issue for the time being, lol...

So here's my update: the play seems to be about 10x worse at the 12:00 and 6:00 positions than anywhere else on the wheel. So I think the swivel pins are definitely bad. The right wheel is as good everywhere as the left wheel's best spot, so I'd say the right wheel is fine.

I've spent about an hour in the RAVE manual trying to decipher how swivel ***** work, and so far I understand they house the CV halfshafts, and essentially fill the role of conventional upper and lower ball joints, allowing the knuckle to turn. But, being much more accustomed to the MacPherson struts on my Nissan and the twin I-beams on my Ford, I'm a bit stumped from there.

You say I should definitely do the hub bearings, which would necessitate rebuilding the hubs and replacing all the seals, right? I have that stuff on hand but seeing as it's wheeling season right now is it possible to replace the swivel pins without rebuilding the hubs? Or do I have to open up the swivel bearing housing and do new swivel bearings? Basically, how much digging is required? I just want to get all the parts on the same boat so I can minimize downtime.

As for swivel pins, I noticed that uppers come in a kit, while lowers come a la carte. Why is this?

Thanks again. Still hoping to order stuff tonight. If I have to dig through the hubs I think I may end up doing brakes at the same time. I'll measure my rotors and see if they have enough width left to be machined or if I need new ones. I'll at least do a pad slap.

Thanks again.