I guess I will be finding out....I am replacing my tie rod ends with a heim type joints...glad to see you back I know its been a tough one for you this past year...hope your doing well
death wobble
Just thought I would post this and hope that it helps someone else that might be experiencing the same thing. After I replaced my front axle setup on the 38 Plymouth last summer, I never really had a chance to drive it due to some other issues. Anyway. I took it out several times this year and noticed if I hit a recessed manhole cover or a good hole in the road at slow speeds, I got the dreaded death wobble. If you have never experienced it, dont. Not worth the wait. I though my lugbolts had come loose or I lost a caliper. My gawd. Scared the peewadding out of me. I took it to a frame shop and they recommended several changes. Get rid of the crap rod ends on the tie rod, reenforce the tie rod with angle iron, take a leaf out of the spring pack, and change the shocks. The old girl has some bounce in her step now and I dont weeble wooble anymore.
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I have run into the same thing Mike with very flimsy tierods! The Speedway kit's tierod material is too small for anything over a 36" long tierod, so in larger vehicles it will flex and create the death wobble. Even small factory tierods of the same diameter can have this issue, so when I use a factory axle as a donor I toss the factory tierod, or sleeve it with larger tubing, and plug weld it every 12" to secure them together.
On the Econoline axle I used in my Falcon I removed the stock tierod and built one up from 1.25" OD heavy wall tubing. I welded in bungs on the end for 5/8" heim joints and bolted those to the stock backing plate arms after I drilled them out to fit the larger bolts.
The larger tierod, plus proper toe in, and kingpin angle will eliminate all the death wobble. I also use the same large tubing to make my drag link, so there's no flex in it either.
On the Econoline axle I used in my Falcon I removed the stock tierod and built one up from 1.25" OD heavy wall tubing. I welded in bungs on the end for 5/8" heim joints and bolted those to the stock backing plate arms after I drilled them out to fit the larger bolts.
The larger tierod, plus proper toe in, and kingpin angle will eliminate all the death wobble. I also use the same large tubing to make my drag link, so there's no flex in it either.
I got DOM tubing from Ron Pope and 5/8's rod ends. He done the left handed threads in 1 end and I bone the other end when I made them up. It's thick wall and ain't cheap but I don't have to worry about flexing. Is it worth going on and putting a steering damper shock on? I used to run HD units on the 4x4's I had. I was thinking about adapting 1 to mine off something.
I doubt you'll need it if the tierod is thick and wont flex. Some guys swear by steering dampers, but on anything with small tires I don't think they're needed. They might make things better, but proper setup, and pieces will do it too.
The biggest problem as Vall mentioned, for my case was the long flimsy tie rod tubing. Once I upgraded to 1" chromoly the problem went away but I put a dampener on anyway. I don't know about you but at 100 plus mph I want a little insurance it ain't gonna happen again. Even remotely.
Reviving this thread. I had a case of death wobble last weekend- hit a recessed manhole cover 40-45 mph and like Jerry Lee Lewis, a whole lotta shakin was going on. what gets me is I have a fresh rebuilt axle/ kingpins, new heim joints, beefy thick wall tubing for drag links/ beefy heim joints and this still happened. car was recently aligned, too. so the only things I can think of would be if my caster is too much (7º) and the only used component is the steering box itself, which doesn't seem worn out. now, my steering feels light on the car, but other than that I'm at a loss. everything I look up online speaks to worn out components which I don't believe I have.
suggestions?
suggestions?
7 degrees shouldn't be the cause as that's pretty much perfect for a long wheelbase car like your '55.
If it's aligned correctly, with enough toe in then you can eliminate that. Not sure what they set it at, but at least 1/8" to 1/4" toe in.
After that the death wobble is all about play in the steering components, so if all are new and tight, then I'd say it's down to either wear in the box, or too small diameter tie rod. On a wide car like yours the tie rod can flex in situations as you described just because it's probably close to 4 ft. long. So hopefully it's large enough, and thick walled enough to eliminate that too, and leave just the steering box as the culprit.
If it's aligned correctly, with enough toe in then you can eliminate that. Not sure what they set it at, but at least 1/8" to 1/4" toe in.
After that the death wobble is all about play in the steering components, so if all are new and tight, then I'd say it's down to either wear in the box, or too small diameter tie rod. On a wide car like yours the tie rod can flex in situations as you described just because it's probably close to 4 ft. long. So hopefully it's large enough, and thick walled enough to eliminate that too, and leave just the steering box as the culprit.
My alignment specs are as follows7 degrees shouldn't be the cause as that's pretty much perfect for a long wheelbase car like your '55.
If it's aligned correctly, with enough toe in then you can eliminate that. Not sure what they set it at, but at least 1/8" to 1/4" toe in.
After that the death wobble is all about play in the steering components, so if all are new and tight, then I'd say it's down to either wear in the box, or too small diameter tie rod. On a wide car like yours the tie rod can flex in situations as you described just because it's probably close to 4 ft. long. So hopefully it's large enough, and thick walled enough to eliminate that too, and leave just the steering box as the culprit.
When I had my axle straightened I rebuilt my steering rods with thick wall larger diameter tubing for 4x4 trucks. Its 1.25" OD with a 0.25" wall thickness. new heavy duty heim joints, too.
So unless my alignment specs are bad, or the steering box is bad? Suppose I could slightly tighten the steering box pre load nut, too, but haven't tried that.
Over the weekend I did give each wheel bearing a snug (tightening the preload to the next slot in the castle nut) just in case they were loose after putting some miles on the car, but I haven't tried driving it with this yet.
The alignment shop is using factory settings for toe in (camber) which wont work for a straight axle. Needs to be something closer to 1/4" toe in. Get a couple pieces of tubing, or sticks that overlap each other and slide them out until they touch the tire sidewalls at the front side at 3 o'clock position. Then move them to the backside and see if you have about 1/4" clearance. If you don't then simply adjust until you do.
sounds easy enough, will try checking that tomorrow, thanks!The alignment shop is using factory settings for toe in (camber) which wont work for a straight axle. Needs to be something closer to 1/4" toe in. Get a couple pieces of tubing, or sticks that overlap each other and slide them out until they touch the tire sidewalls at the front side at 3 o'clock position. Then move them to the backside and see if you have about 1/4" clearance. If you don't then simply adjust until you do.
If I did it right, it should be on the money. I had a fuel line section I cut to length in the front, and adjusted until it was a ¼" in the rear. It was only 3/16" when I started, so it didn't take much to adjust. I sure hope that 1/16" fixes this, ha ha
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Art Morrison wrote me (see below email) that steering dampeners were not uncommon on gasser front ends back in the day. He said VW dampeners from JC Whitney were used. I put one on both my cars. I used pick up truck dampeners from Summit. My death wobble would bounce up and down real hard and scare the life out of me. Im not interested in finding out at 100 plus miles per hour that I should have used one so I put it on both cars.If I did it right, it should be on the money. I had a fuel line section I cut to length in the front, and adjusted until it was a ¼" in the rear. It was only 3/16" when I started, so it didn't take much to adjust. I sure hope that 1/16" fixes this, ha ha
----- Original Message -----
From: Art Morrison
To: [email protected]
Sent: Wednesday, November 17, 2010 6:19 PM
Subject: RE: straight axle
From the pictures I can’t see where the steering box is mounted but unless the box is really worn it shouldn’t cause any problems. This really isn’t all that uncommon and can be cured by putting a Volkswagen stabilizer between the axle and tie rod. It works like a shock absorber and keeps the tie rod from going into the shudder that you have now. You can actually buy them from JC Whitney Product Number: 16037G . You’ll have to make some brackets to attach it your tie rod and axle but there’s about 99% chance it will cure your problem.
Art
Hi Mario,
I don’t see anything there that looks like it would cause a problem. The one thing I didn’t ask was how much caster you have. Straight axles typically require quite a bit more than a normal A-arm type of suspension. It should be somewhere around 8 to 10 degrees. What that will do is force the car to go straight at higher speeds. All you need to do with the type of axle you have is put tapered shims between the spring and axle and tilt it back. You can check the amount of caster by putting a protractor on the front edge of the spindle or someplace else where you can set it to see how far back the kingpin is tilted. One thing about caster is if there isn’t enough you will really know it because the car will be twitchy and really unnerving to drive at about 30 mph or so.
Good luck, Art
I doubt 1/16" is going to make a difference, so whatever caused it will likely still cause it again. Since you've got larger diameter tierod and drag link tubing, that avoids it being caused by flexing, which is another cause on cars using smaller tubing. Mario's suggestion of a dampener might be the cure if everything else is ruled out. I've never experienced death wobble on any of my solid axle builds, so haven't used a stabilizer myself.
Maybe we need to look a little closer at how you set yours up. I got wobble on both my builds. An additional time when I added blocks to the ibeam axle in the 35 years ago which changed my caster. And it went away when I removed the Blocks so you are right about the caster being correct.
Usually adding blocks between the axle and the springs will increase kingpin angle, and that's never a bad thing. A little too much angle is better than not enough. Especially so with short wheelbase vehicles. I'm about 10 degrees on the Austin, which works really well on the 89" wheelbase, and narrow width.
I'm at 7 degrees on the '39, and I was at 6 before I also added 2" blocks between the axle and springs.
I'm at 7 degrees on the '39, and I was at 6 before I also added 2" blocks between the axle and springs.
I have wedges on mine to give me a 7º caster angle. I drove my car to Pomona (on display for the Winternationals) on Friday and it drove there without issue, though it felt like it wandered a bit more than it used to, but it could have been the crappy LA freeways, too. No wobble there. After I get my car back I'll take another look at my steering box. I believe it's fine, but I can also adjust the set screw on the top to tighten the pre load, too.
How much side to side play in the steering wheel with the car sitting still? Careful not to tighten the adjusting screw too much, and bind the box, which will wear out the gears. I usually use a stubby screwdriver and two fingers to adjust the screw so I'm not tightening it too much.
Well, I drove the car home from Pomona today and had 3x instances of death wobble before I even reached the freeway- all happen around 40 mph. I got the car home OK without anymore incident, though it did feel "loose" and like it was vibrating in front, which isn't good. When I got home I lifted the front on jackstands and it appeared to have some end play before turning the wheels. I ended up tightening the adjustment screw a good turn and a half before the "bind" (resisting to recenter the wheel) occurred, so I backed the adjustment screw probably an ⅛ turn and tightened the jamb nut. I ran out of daylight at this point and didn't feel like taking it back out so I'll give it a try tomorrow, but the wheel feels much tighter now. at this point:How much side to side play in the steering wheel with the car sitting still? Careful not to tighten the adjusting screw too much, and bind the box, which will wear out the gears. I usually use a stubby screwdriver and two fingers to adjust the screw so I'm not tightening it too much.
1- will confirm I have equal tire pressure on both sides.
2- will test drive it tomorrow and see how it drives.
3- will check my scrub radius. I can't change this without changing my wheels, but I'm curious to see how much I have.
4- Will likely reinforce my steering arms. they are the speedway ones, and perhaps they are flexing while driving- maybe not enough for me to see, but it's one more variable I can remove from the situation.
5- thinking about a stabilizer, but if I go this route I want it to be the last resort so it's more insurance rather than a band aid.
Is your tie rod mild steel or chromoly steel? If it’s not chromoly change it. Order a 1” with your exact length and thread you need from Morrison. If it’s mild steel it’s flexing after one side hits a bump or uneven pavement and sending the shock across back and forth causing the shudder vibration. The dampener prevents that from happening. I did that test. Purchased it after I removed the 5/8 mild steel and replaced it with 1” black pipe. Problem went away.
If you do have chromoly then your caster is just not enough like Vall had mentioned. You last mentioned the car was not tracking right so go more Angle. If it was me the steering dampener cure is insurance so I won’t wreck my car. Not a bad thing.
If you do have chromoly then your caster is just not enough like Vall had mentioned. You last mentioned the car was not tracking right so go more Angle. If it was me the steering dampener cure is insurance so I won’t wreck my car. Not a bad thing.
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