So I took the day and ripped into the front suspension. Here's what I did:

Pressed new bushings into panhard rod (see seperate thread)

Removed caster-corrected radius arms, replaced with stock radius arms, new bushings

Replaced panhard rod (see seperate thread)

Used all new bolts on radius arms and panhard rod

So, it's really anyone's guess what cured the death wobble. Personally I'm of the opinion that the panhard rod bushings are the main culprit. I've solved DW before by only changing the panhard rod bushings, but since I was in there, I went whole-hog.

I wanted to change the radius arms anyhow and put them back on the Serious One (which is quite skittish right now...).

Anyhow, I went on my DW inducing test track and no DW even at high speeds, so I'm fairly confident that it's cured. Confident enough to start driving the truck daily.

Well, that's all for now.

Confident enough to start driving the truck daily.

Well, that's all for now.

I guess this means you'd really like to receive the windscreen wiper switch:flipoff2:

It's not cured. You've just prolonged the arrival of symptoms for a short period of time. Nothing a few girl scouts can't fix...

I thought you had this thing licked last year? You past posts on the DW are what led me to my panhard bushings, after I spent tons of time and $$$ on suspension, bearings, alignment etc..:mad3:


BTW and totally off topic. A fireman I work with just bought a brand spankin new Range Rover. It drives him nuts when I say I drive a Land Rover too. He looks at my 130 and just shakes his head and says "that thing is fawkin ghetto dude, that ain't a Land Rover" Gotta love the new breed of Rover owners:D

damn what kind of firefighting does he do? Guess I picked the wrong occupation. Glad to hear you are driveable again Mike

-ben

damn what kind of firefighting does he do? Guess I picked the wrong occupation.

-ben

I could own a new RR also but I choose to live within my means. Overtime is plentiful in Los Angeles.

I could own a new RR also but I choose to live within my means.

So you're the one bringing down the economy, eh?

C'mawn, be a good 'merican and spend some $ you don't have and have no chance fo ever earning, it's the 'merican way!

So you're the one bringing down the economy, eh?
Nope...it's the cholos shooting firecrackers in the hills over soto that really cause the overtime.:flipoff2:
130 is way more tits than a new rr:smokin:

Overtime is plentiful in Los Angeles.

After Rodney King tried to burn that place down in th 90's I guess they aren't taking any chances.

:flipoff2:

-Jeff

...And just so that I dont aid in the hi-jacking of this thread, I prdered panhard bushes and bolts with the correct shoulder dia.
Suppose it's easier than doing the swivel pin preload, so i'll try it first.

Nope...it's the cholos shooting firecrackers in the hills over soto that really cause the overtime.:flipoff2:
130 is way more tits than a new rr:smokin:

Man I'm embarassed to admit I understood everything you said.

:laughing:

Actually checking your swivel pin preload is MUCH easier. Do that first.

Nope...it's the cholos shooting firecrackers in the hills over soto that really cause the overtime.:flipoff2:
130 is way more tits than a new rr:smokin:

LOL:laughing: damn cholos, actualy chasing fires up the hills are about the only exercise I get nowadays.

Whats your avatar picture? Sergio Mendes?

Michael, sorry for the hijack:D

Michael, sorry for the hijack:D

Worth it! :laughing: Any hi-jack is a good hi-jack. :flipoff2:

Actually checking your swivel pin preload is MUCH easier. Do that first.

Yeah, what he said!

(I agree about the 130 although I did like driving the brandy new ones with the plastic still on them:flipoff2:)

...And just so that I dont aid in the hi-jacking of this thread, I prdered panhard bushes and bolts with the correct shoulder dia.

So what's the "correct shoulder dia"? I'm just using 1/2" UNF.

So what's the "correct shoulder dia"? I'm just using 1/2" UNF.

Um, something about a picture being worth a thousand words.

http://www.tawayama.com/blog/panhardrodbolt.jpg

:flipoff2:

So what's the "correct shoulder dia"? I'm just using 1/2" UNF.
Ummmmm yeah. I kinda did the same thing and tried to convince myself it was all gonna be just fine. Since watching this and other pertinent threads, I am gonna point the stink finger at my home depot bolt...now, a little background on the CBness of that move. I bought the right one and they didn't send me a nut, so I drive around to all the hardware stores and nobody can match the pitch and thread exactly—so I got the next closest thing I could find.
Avatar is of Throbbing Gristle. They pretty much invented industrial music and I think 2 of the guys are now girls and the girl is an ex-brit-porn star.
But check out that RRC!:flipoff2:
http://www.releasemagazine.net/Pictures/tgflowers.JPG

Um, something about a picture being worth a thousand words.

http://www.tawayama.com/blog/panhardrodbolt.jpg

:flipoff2:

So did they change bolt and bush diameters somewhere along the line?
I know my 85 RRC takes 1/2" bolts because I had to weld up and redrill/machine the slogged out bracket the other weekend.

There's no way your bolt would fit my truck.

Once the panhard rod bolts are tightened fully and kept tight the shear forces are taken by the inner sleeve of the bushing and the mounting bracket,
not the bolt itself.So long as the bolt is strong enough to squeeze the mount tightly against the bushing sleeve, it doesn't necessarily have to be a new unworn bolt.
Bill.

So did they change bolt and bush diameters somewhere along the line?
I know my 85 RRC takes 1/2" bolts because I had to weld up and redrill/machine the slogged out bracket the other weekend.

There's no way your bolt would fit my truck.

It was a 'pressed' fit to get it in.

AFA smaller bolts in bigger holes is concerned, I always think it's a bad idea. IMO the shoulder diamer ought to match the inner diameter of the bushing, otherwise it'll be sloppy and sloppy = DW.

http://www.tawayama.com/blog/panhardrodbushing.jpg

Ok, so I'm an idiot. Apologies for that up front. My caliper wasn't zeroe'd out when I made my measurements.

Here are some new pics of the panhard rod bolt, bushing and caliper set to zero.

Sorry. :rolleyes:

http://www.tawayama.com/blog/zeroedcaliper.jpg

http://www.tawayama.com/blog/panhardrodbushing2.jpg

http://www.tawayama.com/blog/panhardrodbolt2.jpg

IIRC, I've used 1/2-13 bolts for panhard rods and IIRC(again) 7/16-14 for radius arms.

I often put large grade 8 washers on each side of the mount to help the bolt take up the slack. Counteracts the bolt shoulder as well.

JP

Once the panhard rod bolts are tightened fully and kept tight the shear forces are taken by the inner sleeve of the bushing and the mounting bracket,
not the bolt itself.So long as the bolt is strong enough to squeeze the mount tightly against the bushing sleeve, it doesn't necessarily have to be a new unworn bolt.
Bill.

That's my theory too. If you feel a clunk as the panhard shifts at either end, then it's not tight enough. UNF (rather than UNC) lets you get them tighter with less torque.

It doesn't cause death wobble, because before I rewelded and drilled my mounts, it would only shift under "enthusiastic" cornering.
To cause death wobble it'd have to be really loose and rattling.

My theory is that the shoulder diameter should be the same as the inner diameter of the bushing. The hole in the bracket should be the same diameter as the bolt. Loose bolts and wallowed out holes are sloppy.

I know I've cured DW before with new bushings, so I'm just reporting what I've done. New bolts aren't hard to find, so WTH wouldn't you?

YMMV...

My theory is that the shoulder diameter should be the same as the inner diameter of the bushing. The hole in the bracket should be the same diameter as the bolt. Loose bolts and wallowed out holes are sloppy.

New bolts aren't hard to find, so WTH wouldn't you?



You gotta have some clearance! If they're too close in diameter, you'd have a horrible time putting them together.

Why not? Lazy, cheap, lazy. Only excuses I can see. As cheap as hardware is, there's nor eason not to have a pile of new stuff around just-in-case. I'm always very gratified when I can stroll over to the bol bin and get a brandy new one of whatever it is I'm working on. If I don't have it, a walk across the street to my fastener supplier is in order and I buy five or ten of whateve rit is. If I needed it once, I'll need it again.

As for shear forces being taken up and borne by other than the bolt, I'm not buying it. Gonna have to think on that one awhile. Maybe talk to my buddy the PE.

Peace,
PT

As for shear forces being taken up and borne by other than the bolt, I'm not buying it.

I'm not so sure even those who are promoting that idea would run their p-hard rod on clamping force alone. Run it w/out the bolt and a big clamp? No way.

As for shear forces being taken up and borne by other than the bolt, I'm not buying it. Gonna have to think on that one awhile. Maybe talk to my buddy the PE.

Peace,
PT

He'll back us up, I'm a PE too.:flipoff2:

Do some googling for theory of bolted joins.

Yes, that is the theory. A bolted joint in shear should be tightenedd to proof stress and the load it taken by the friction between the clamped bits and not the bolt. At least when properly designed. This give a stronger attachment and prevents load cycling on the bolt.

The panhard road supports on Rovers are not well designed to work that way, but that is the intent and that is why they are sloppy unless the bolts are tight as hell.

The panhard road supports on Rovers are not well designed to work that way, but that is the intent and that is why they are sloppy unless the bolts are tight as hell.

Yep, get the finest pitch bolts you can and torque them up well. For normal size wheels it seems to work okay.

Of course those running big wheels, pumped up steering boxes and other such mods will be way past the limitations of a 1/2" bolt.

I'm not so sure even those who are promoting that idea would run their p-hard rod on clamping force alone. Run it w/out the bolt and a big clamp? No way.

No one suggested running without bolts. I just pointed out that the bolts are primarily intended as the clamping medium and that if you are depending on the bolt to cope with the shear forces you are doing it wrong. Its exactly the same as with shackle bolts on leaf spring Landy's particularly Series 1's with stepped BSF bolts. Fail to keep the bolts snugged up so that the shear forces are taken by the inner sleeve of the shackle bushes and they will break regularly in off road conditions. If the shackle bolts are kept tight they will last forever even when the bushing is completely shagged.
Bill.

No one suggested running without bolts. I just pointed out that the bolts are primarily intended as the clamping medium and that if you are depending on the bolt to cope with the shear forces you are doing it wrong.

Oh I know, but I'm just taking it to the extreme example where the idea of running the bushing w/out any bolt, but using some sort of clamping mechanism outside of the bushing, relying on the clamping force alone, scares the BeJeeezus out of me.

I don't think anyone with half a brain would really try it. But, go ahead...surprize me! :flipoff2:

Nice plastic dial caliper. I run one myself.

JP

Yes, that is the theory. A bolted joint in shear should be tightenedd to proof stress and the load it taken by the friction between the clamped bits and not the bolt. At least when properly designed. This give a stronger attachment and prevents load cycling on the bolt.

The panhard road supports on Rovers are not well designed to work that way, but that is the intent and that is why they are sloppy unless the bolts are tight as hell.

And to further distance this situation from the theory, does the bushing composition even allow for this to realistically happen?

What is the inner sleeve of the bushing made out of? Steel or some bronze alloy? Is it a continuous sleeve, or is it split down the middle (e.g. made from sheet that was rolled into a sleeve)?

If the sleeve is a continuous tube of steel, then possibly it can transfer the sheer to the mount and away from the bolt. But if it is a softer alloy, or rolled-sheet instead of a continuous tube, fat chance it won't deform and place all of the sheer on the bolt.

Nice plastic dial caliper. I run one myself.

JP

If I wasn't such a cheap bastard, I'd know what both of you were getting for Ramahanakwanzmas!:flipoff2:

And to further distance this situation from the theory, does the bushing composition even allow for this to realistically happen?

What is the inner sleeve of the bushing made out of? Steel or some bronze alloy? Is it a continuous sleeve, or is it split down the middle (e.g. made from sheet that was rolled into a sleeve)?

If the sleeve is a continuous tube of steel, then possibly it can transfer the sheer to the mount and away from the bolt. But if it is a softer alloy, or rolled-sheet instead of a continuous tube, fat chance it won't deform and place all of the sheer on the bolt.

It's a simple Metalastic bush for heavens sake ! Seemless tube on both inside and outside all vulcanised together. And you guys can dismiss it all you like but the way I described it is how it was intended to work and how it does work. If the Panhard mounts do not clamp against the inner bush sleeve, the axle will move laterally beyond the compliance in the rubber unless you use press fit bolts which would be extremely difficult to remove in a year or so when you need to replace the bushings again.
Use a bit of muscle and tighten the fawking bolts up for gods sake.
Bill.

Just to put a lid on my DW, I replaced the bushings, tracked down some HD nuts n bolts with proper shoulder, did the damned thing and did it tight...
the Great White Hope handles like it's on rails. Really a pleasant surprise—thanks for all the jibber-jabber!

It's a simple Metalastic bush for heavens sake ! Seemless tube on both inside and outside all vulcanised together. And you guys can dismiss it all you like but the way I described it is how it was intended to work and how it does work. If the Panhard mounts do not clamp against the inner bush sleeve, the axle will move laterally beyond the compliance in the rubber unless you use press fit bolts which would be extremely difficult to remove in a year or so when you need to replace the bushings again.
Use a bit of muscle and tighten the fawking bolts up for gods sake.
Bill.

Bill:
I'm not trying to argue wiht you, but better understand this principle.

How tight can we get the bolt, and how much force can we exert in the pinching fashion?

Now, let us say we had a means to achieve this pinching without the bolt.

Could the vehicle coming down onto the Panhard rod exert more force on the rod than the clamping force? If so, without that bolt, the panhard rod would come loose. I've not looked it up, but my copy of Mark's is right handy and I will look up the shear limit of a 5/8" fine thread bolt. I find it difficult to believe that I could pinch that bushing together such that it could withstand a force that would shear the bolt-ie, the arrangement we would have if we were solely relying on the pinching action and not the through-bolt.

PT

Bill:
I'm not trying to argue wiht you, but better understand this principle.

How tight can we get the bolt, and how much force can we exert in the pinching fashion?

Now, let us say we had a means to achieve this pinching without the bolt.

Could the vehicle coming down onto the Panhard rod exert more force on the rod than the clamping force? If so, without that bolt, the panhard rod would come loose. I've not looked it up, but my copy of Mark's is right handy and I will look up the shear limit of a 5/8" fine thread bolt. I find it difficult to believe that I could pinch that bushing together such that it could withstand a force that would shear the bolt-ie, the arrangement we would have if we were solely relying on the pinching action and not the through-bolt.

PT

Paul, I think if you got the specs on the squeezing power of a 1/2'' or 9/16'' UNF bolt and nut you would find it is considerable. If I counted them in the first place I would have lost count of the number of customers that have brought Rovers in, complaining of wheel shimmy. after a few minutes work tightening up the panhard bolt and nut they are on their way problem solved,same bolt and bush, with probably a little more clearance than when new, but problem solved. Generally Landrover front suspension components are long lasting and relatively trouble free, but there are 6 bolts that should be checked regularly for tightness, 4 radius arm to axle bolts, and 2 panhard rod bolts. I know you can buy new bolts easily and cheaply over there, and in the larger centres we can too, but I have spent many years repairing and maintaining LandRovers in small towns and remote areas where new stuff isn't always easy to get hold of, and you learn to make do. Even on old leafers I've reused shackle bolts that have worn off 25 percent of their diameter due to being left loose. They still had more than enough clamping power to pull the shackle plates up hard against the bushing tubes and work just as good as new ones.
Bill.

I'm going to resurrect this thread and give another update.

The DW did come back actually on a few occasions, and I re-checked the swivel pre-load, ended up replacing all of the rear suspension bushings, still the DW would return on rare occasions.

In desperation I checked the front alignment. It was WAY off. The uneven tire wear tipped me off.

I got it to within 1/4 inch toe in, and that's what finally caused it to go away 98-99%. The question I guess is, how much DW is really acceptable? How much do we like driving with that butterfly in our stomach everytime the steering wheel shudders over a pothole?

Answer: I don't like any of it. So, I chased it down this far. I probably could use a new steering damper, which might take away the remaining 1-2% DW, could probably tighten up the pre-load one more shim, etc...

I'm waiting for my new tires and a new alignment before I chase it some more.

New Tie-rod ends might probably help too...mine aren't bad at all, but they can always be a bit tighter I guess.