Death wobble, but not quite lethal yet… and catalytic converters

[terryjm1]

I have been working on a 96 D1 slowly for a while now. Just today I replaced the catalytic converters. One was rattling and I decided to go ahead and replace them when I got code a for low catalyst efficiency on its first really demanding drive after I sorted out some other problems.

The new cats came from a vendor in Canada. They look pretty good and came as a split y-pipe that I am sure made shipping less costly and the really nice part is it made installation easier. The fit was mostly good but the driver side was almost contacting the cross member. A little work with a pry bar solved that problem. The cats are a lot smaller than OEM and I am sure they won’t last 155,000 miles or 26 years but they probably will last as long as I will need them. Splitting driving between 5 vehicles means everything lasts longer.

No more rattles and I am surprised it seems to run with a bit more power. A good day in the Rover garage! I now have 700 miles of personal drive time on this one and am really starting to like the automatic. I still prefer a manual trans but the D1 auto is a nice driver.

However, on my spirited test drive after installing the cats i noticed a very slight and brief appearance of the dreaded death wobble. I would call it more of a death threat wobble.

Unlike almost everything else that was worn out and original, there clearly has been some steering work done. Tie rods and other joints in the steering have been replaced and it appears to be not long ago.

Anyone know what is the most common cause of death wobble?

Now it is time to box up those cats and sell for a little more than it cost to buy the new ones.

 

[boxster]

Steering Damper or stabilizer, wheel balance, tire tread separation.

 

[Tugela]

Steering Damper or stabilizer, wheel balance, tire tread separation.

Those are the easy things to check. Other possibilities include swivel pin preload. Given the vehicle's age you may just want to rebuild them. It's pretty easy to do, the parts are cheap, good resources are out there to understand the project, and the resulting improvement in handling is notable.

 

[p m]

okay, for death wobble on D1/RRC/D90/110 there are as many opinions as ... you know what.
So, in my experience, by far the most-frequent cause of death wobble on these trucks is one or both Panhard rod bushings. The driver-side one goes first, the rubber softened by the constant power steering fluid drip.

Piece of cake to rule out, if someone shakes the steering wheel side-to-side by about 2 inches for you.

Going down the list in decreased frequency:
Loose TREs
Play in the steering box at the center position
Loose steering shaft joints
Loose swivel pins
Loose bolts holding the steering box to the framerail
Loose pitman arm (worn splines or loose nut)
Way down in frequency - badly worn and loose radius arm bushings at the axle end

Wheels out of balance or out of round could promote the shimmy, but they have to be pretty bad.
Steering damper being a cause for death wobble? Never. But if yours is super soft, you can extend your agony by installing a new unit.

 

[terryjm1]

Definitely have play in the steering.
Before I replaced the ps hoses, it had more than a drip for who knows how long.
It is definitely due for a steering dampener. I almost replaced it while I was underneath working on the catalytic converters but decided to wait until it needs an oil change.

I will check those items first and then look at the rest.

Also, the swivel balls are not leaking which makes me think there may be nothing left to leak out.

Thanks for the tips.

 

[MM3846]

steering dampers do not affect death wobble. all they do is mask a little wear in the front end or inconsistencies in the road.

in all solid front axle setups, death wobble is usually caused by
#1 something in the trackbar/panhard rod loose, worn, etc.
#2 ball joints/kingpins/swivels

the best way to find what's loose is to leave the truck OFF when the key to ON to unlock the column, have someone rock the steering wheel back and forth fast and hard (bounce it off the "play" from side to side) and then you lay down on the ground and watch everything move. something will be moving that shouldn't be.

 

[WaltNYC]

front shock bushings were the culprit in my case. Add that to the list of possibilities

 

[discostew]

Those are the easy things to check. Other possibilities include swivel pin preload. Given the vehicle's age you may just want to rebuild them. It's pretty easy to do, the parts are cheap, good resources are out there to understand the project, and the resulting improvement in handling is notable.

This is the place to start. Get yourself a good fish scale. A small one for under 5lb fish. Like Tugela says, improvement is notable. Nothing makes as big a difference in handling. It’s easy as long as you understand the procedure.

 

[terryjm1]

front shock bushings were the culprit in my case. Add that to the list of possibilities

I’m working on another D1 now with more pronounced death wobble. I have replaced all tie rod ends, radius arm bushings and panhard rod bushing, All OEM parts. It even has new sway bar links. It only has 55,000 miles so I will leave swivel pin preload as my last stop. How bad was the wobble with your worn out shock bushings?

Would being out of alignment cause or make the issue worse?

 

[discostew]

I’m working on another D1 now with more pronounced death wobble. I have replaced all tie rod ends, radius arm bushings and panhard rod bushing, All OEM parts. It even has new sway bar links. It only has 55,000 miles so I will leave swivel pin preload as my last stop. How bad was the wobble with your worn out shock bushings?

Would being out of alignment cause or make the issue worse?

Yes. But the only adjustment is toe. Swivel pin preload should be your first stop. That and any loose panhard rod bushings or tie rods.

 

[terryjm1]

Yes. But the only adjustment is toe. Swivel pin preload should be your first stop. That and any loose panhard rod bushings or tie rods.

All the other stuff (panhard bushings, tie rods, radius arm bushings, and more) was obviously needed just by looking at it all. I know the alignment is off as well, but not a huge amount. I’m going to replace the shock bushings anyway as they are rough. I just ran out of time today. The shocks are OME and i am impressed they seem to be working very well considering how rotten the shock bushings are. I accept swivel pin preload makes sense as the first stop but everything else was so crappy and needed to be done anyway, swivel pin preload is now the last stop. I was hoping with such low miles that wasn’t the problem.

After the shock bushings are done, everything rubber in the front end will be new. New tie rods are now installed as well. While they still moved it felt like gravel inside. I fully accept I am probably headed for swivel pin preload. Im sure the swivel ball seals will disintegrate soon as well. . Fortunately the swivel balls look pretty good, no visible pitting. I’m not relocating the steering dampener because I think it is the problem. It needed to be replaced anyway. When I took it off and went for drive without it, the wobble was a lot worse, apparently masking the problem.

 

[discostew]

I’m gonna tell you this Terry. If you do the swivel housing preload the correct way. No shortcuts. This truck is going to drive so damn nice you’re going to order seal kits and do all your Discos. It’s the first thing to do. Go find a good fish scale.

 

[terryjm1]

I’m gonna tell you this Terry. If you do the swivel housing preload the correct way. No shortcuts. This truck is going to drive so damn nice you’re going to order seal kits and do all your Discos. It’s the first thing to do. Go find a good fish scale.

I will admit, I have been hesitant to do that job as I haven’t done it previously. I guess I just need to dive in and do it.

 

[discostew]

Once you see what you’re doing it will make perfect sense get an assortment of shims but sometimes you don’t even need them cause your taking them out to tighten it up.

 

[Flyfish]

Not sure if you replaced the steering damper but if not, might try that. Also, check for play in the rubber joint in the lower steering column assembly.

 

[terryjm1]

I replaced the steering dampener today. It greatly reduced the wobble but I know it didn’t solve the problem. It still wobbles just a bit for a few seconds when it hits 53 ish mph.

 

[Knightspirit]

I had a severe death wobble on my D1 - even after replacing all of the tie rod ends and bushings. i was stumped. I finally figured out that it was indeed the pan hard bar bushing - must have put it in wrong or had a bad one, because after purchasing a new pan hard bar and installing it, it was totally gone. Also did the swivel pin preload adjustment - and I have to say that my rig drives like a dream now - even with a two inch lift and bigger tires. Re-check that pan hard bar.

 

[lunchbox]

Sounds like you just have a tire out of balance. If it’s only shaking at certain speeds, that’s usually a balance issue. When I think of death wobble, I associate it with bump steer. Everything you’ve done is to solve bump steer…you know…hit a bump and you almost die. Sure, replacing bushings, setting preload, and packing bearings can fix a lot of driving issues. But those symptoms should not be speed specific. It should always shake, and continue once it starts. But yours sounds more like a tire.

 

[Gordo]

Swivel preload. A damper can sometimes mask the problem. I had a RRC 25 yrs ago that went wild on expansion joints. I use a fish scale to measure.

 

[discostew]

So when you go looking for a fish scale it needs to be a smaller one. I think mine is for a 10 lb fish max. I feel like a 5 lb would work best. I look up the spec every time but I think 2 1/2 to 3 lbs preload is what you’re looking for. You know it’s too tight if it won’t return to center after turning.
Keep in mind that reading is with no swivel housing seals installed. Land Rover says dry, but I find the reading to be more reliable with a little gear oil on that lower bearing. I usually have them hanging off the axle tube so I don’t have to dis assemble it again.
Also don’t put the seal and its retaining plate into the assembly till you’re done assembling the top pin and brake line bracket. Without those 2 bolts the housing will drop and damage the new seal.