VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Death Wobble

New front wheel cylinder installed, crusing home downhill going around 47mph hit a pothole and the front end started vibrating violently. I immediately took my foot off of the gas and she didn't stop vibrating until I slowed down to around 25mph. I took her back to the shop and they said front end was tight, but had a little play in the steering box. Some have suggested tires as I have a straight axle and running bias ply Denman's with stock 16" rims. Suggestions?
Mike
P.S. The fellow at the shop referred to my experience as the "Death Wobble", scary.

Mine was caused by the shocks. After I converted to tube type shocks mine went away. Mine was so bad it would take me clear off the roadway.

More commonly called "shimmy".....common on straight axle cars when something is out of kilter.
Could be alignment, too much ortoo little caster or something loose.
Most modern shops would have no idea as how to adjust the castor.

I would re-adjust the tie rod and drag link ends (if adjustable) and also the steering gear. A little play in each can add up. Looseness is usually the cause of shimmy in my opinion.

Also double check the toe in. A little extra toe in will reduce the tendency to wobble. Yes it will wear the tires a little more but very few of us drive enough each year for that to make a difference in tire life. They will rot or crack before wearing off the tread.

Fortunately the shop I bring her to is old school, they know what to do so my next visit will be front end check up and parking brake rebuild
Thanks all
Mike

Tiny
How did you convert to modern style shocks, is it a kit or simple mod? That sounds interesting.
Mike

My Canadian 38 Master came with tube shocks from the factory. The manual even shows how to fill them up. I have never seen a fillable tube shock but apparently that is the way they were.

A Place called Chassis Engineering sells a kit with tube shocks for the front of your 38. I bought the kit a few years ago for a project 38. It bolts right on and maybe the only change would be slightly longer U bolts. Normally these straight front axles do not shimmy or vibrate. I have none of those problems with mine.

I used the mounting hardware off of a '39. If a comprehensive kit is offered that's the way to go. FWIW I had my original lever action shocks rebuilt & still had the problem. I had the front end checked & it was within spec. I lowered my tire pressure to get less bounce. I added toe-in. I replaced my king pins. The only thing that stopped it in my case was the tube shocks. My first drive after installing the tube shocks was to the trigger point that took me all the way off the highway. I had a death grip on the steering wheel when I got to that spot but it was quite smooth. I have not had a single incident since.

Are these "tube shocks" aka gas shocks. I visited chassisengineeringinc.com and saw a gas shock kit for rear only, but not the front.
Mike

Do a quick search for "shocks" in this forum as we've had some discussions in the last year. You want regular shocks not the gas charged as the gas charged shocks will make the ride really firm.

Tim's right. I'm not referring to gas charged shocks, just regular old fashioned round shocks.

I don't know why the front shock kit isn't showing up in the catalog. I would,call them to see if they still carry it. If you look up item 360702772158 on Ebay Motors, there is a vendor selling that kit. They call themselves Gearhead Enterpizes.

Here's a kit made for a pickup. I don't see why it wouldn't work on a straight axle car. <CLICK>

The kit old216 is talking about sounds like a better deal. Here's the kit. <CLICK>

Just remember that if you drill holes in your frame rail you should weld slugs through the holes to prevent crushing the frame as you tighten the bolts.

I think an important point here is that the frame on the car and the one on the truck are completely different. The car has a fairly thin walled box frame whereas the pickup I believe has the U frame design. Everything that is attached to the Master frame through the sides has a reinforcement inside. The kit just bolts onto the same place where the old shock mounted on the frame.

We had to add slugs to my '38 when we put the '39 mounts on because there was no reinforcement in/on the frame. The frame would have crumpled. If the ebay kit mounts to the existing holes, that is indeed the way to go. No muss, no fuss. I know nothing about the truck frame other than reading posts in the past by people who said they put the truck kits on their cars. I have no idea what modifications they had to do to make it work. I wish I'd known about that ebay kit when I did mine if indeed there's no drill/cutting involved. I'll remember that in my next lifetime.

Hi Mike,

Could you have bent a rim? Have you jacked up the front end so you can spin the tire and see if the rim/tire is wobbling?

Good luck, Mike

Check for missing tire weights. A hit hard enough could possibly throw one off. Also, my 99 Cherokee had a horrible death wobble (common on Jeeps) and it disappeared when I got new tires. Go figure. If you jack up the front end, jack stands under the frame (not the axle), grab a hold of one of the wheels and shake the crap out of it. Spin it to check for trueness and wobble, steer it by hand to check for play. Do this on both sides. If it all appears tight, give the tires a kick and listen for vibrations.

Good luck!

This was done at the brake and front end shop. I suspect it is a combination of all of the above. I will get tires balanced, steering box play removed if possible and front end aligned. Thanks for the suggestions.
Mike.

Went for a spin Friday exceeding 45mph with no problem, but I turned down a side street going about 25mph hit a small bump and the front end started vibrating like crazy. I'm going to lift front end and start looking for any looseness in the suspension as well as the steering. I suspect it is steering related. Keep you posted.

I'm wagering a cup of coffee it's the shocks. You'll spend many hours and dollars chasing your tail. Eventually, because nothing else works, you'll change the shocks and all will be right in the world again. Your symptoms are identical to mine. The steering wheel violently turns side to side. It HAS to be in the steering because of that right??? That was my reasoning. Nope, it's the shocks.

you are probably correct, but I will add that I seem to have a lot of play in my steering. I will order the tube shock kit for sure. Keep you all posted.
Mike

Been thru all this trying to fix death wobble, put new shocks on , it was no better, it turned out to be general minor looseness in all the steering linkage components, just a little wear in all components caused the problem . Above all repair your steering box first, Do it quick or your going to kill yourself or someone else.the wobble put a HUGE strain on old parts :(

tire pressure works wonders. i had my front tires overinflated making my frontend rigid. My tube shock mod kit will arrive Tuesday making it better and my steering feels much better. Keep you posted.

How much air did you have in the tires? For bias ply tires should not be over 30 pounds cold.
Chevrolet called for 28 pounds.