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.

probably around 40-eek

Holy Carp!! That's high. Hope that fixes it for you.

Rides like a Cadillac, but will install tube shocks probably next weekend and rear are scheduled for down the road. Weird, but I thought the suspension was so archaic that tire pressure wouldn't make that much of a difference so a slow leak in one tire caused me to overfill all of them. Amazing how lowering tire the pressure caused the steering to be more responsive. I guess i underestimated 1938 technology, she never fails to amaze me.

Just be aware the the now correct pressure is covering-up a problem in the susupesion/steering that the higher pressure revealed.
Also if you think it rides nice now a ride in a Master Deluxe with independent front suspenion would amaze you..

X2 , pretty sure you still have problems in steering :(

received the tube shock kit, but no time to install especially with the 100+ degree heat wave we are having.

Ive had the tube shock kit for a year and haven't installed, i need longer u bolts. I did discover the bushings in the linkage to the shocks was hard as rock at best and crumbling to nothing at worst. i ordered new bushing sets from The Filling Station and installed, too loose. My temporary fix consisting of rubber bushings I bought at lowes, and trimmed held in place by larger washers was much tighter. I will install tube shock kit but vibration after a large bump is nearly gone, just feels like a truck up front.

After reading all of this, a question comes to mind. I have a 1937MD, and was wondering what the adjustment is on the ball joints for the tie rods and drag link?? I see there's an adjusting plug with a cotter pin through it on them! Any help will be appreciated.
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Joes37

The instructions are on page 75 of the 1938 shop manual.......should be close to that in the 1937 manaul

Thanks Gene, I just have to find my manual now! Also, could I change out the old ball joints that are welded in now, to the ones that have threads on them? or no? Thanks.
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Joes37

My suggestion would be to disassemble the stock set-up and adjust. It is designed for the springs to cushion the road shock. There were some modern style replacements made that did not have that feature. As long as the center balls are not worn the other parts are available as a kit if required.

Thank you Gene for your suggestion. But, can just the BALL'S themselves,
be replaced with new ball's with the THREAD'S on the one end for the castle nut? Since I don't have a welder to weld in the ball's without the threads. Or would there be a problem with clearance? Thank's PS, The filling station has these!
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Joes37

The balls were not seriviced as a part by Chevrolet.

I realize this is an older thread. I remember following it with a lot of interest when it was active. It motivated me to make sure the front end and steering were in good shape on my car.

The reason for this post is that for the first time I experienced the "Death Wobble" the other day It really caught me by surprise because I have driven car over 3300 miles and never had an issue. And most of that driving was with very bad lever arm shocks. I converted to telescoping shocks just before the Fall Southern Tour this year.

Winter here has been fairly mild so I have been able to drive the '37 quite a bit. Last week I was driving along one of our busier through streets at about 45 mph. Obviously I hit a bump and boy did the steering wheel go crazy! It went away after I had slowed down to about 20 mph. My first thought was a flat tire so I pulled into a high school parking lot. Everything looked fine. I pulled at the top and bottom and sides of the front tires and everything felt fine. The rest of the drive was normal.

So it appears that I have another task for the winter project list. I have to wonder if one of the springs that cushion the road shock to the balls in the joints has broken. I had to replace a broken one before I started driving the car. I do have a NOS steering shaft and bushings for the steering gearbox so will go ahead and install them if i do not find another problem.

Tube shocks cured mine. It'll be interesting to see what you find.

I had a loose drag link end joint, that fixed mine.

I also had a link joint that wobbled in the arm. It had been welded instead of crimped but didn't hold.

Hi Tiny, Uncle Ed, and Chipper,

Thanks for the responses to my revival of this old thread. I thought it might be of interest especially considering that it happened after I did the shock conversion.

It will be a while before I get to this work. I was called to the southwest office location for some remedial training with my supervisor. Interpretation: I am in Scottsdale for a coupe of weeks enjoying time with Doris and the slightly warmer weather. I do plan to visit a couple of the auctions next week.

I will post my findings.

Rusty,

Sure fix. Slow the h..l down. Those ol' 37's and 38's weren't meant to travel over 35 MPH. The speedometer may indicator may suggest a higher speed but it won't go over 45 without something falling off and entering the "Death Wobble" zone.

Suggestion. Jack it up and strongly grab the wheels at four alternating points and see if you have play. If not then it may be the shocks. Back when the ffactory boys wind tested those critters, they thought the wind tunnel was just acting up so they got an airoplane to drop one car with no parachute from 6 thousand feet AGL (above ground level). Result the darn things still wobbled and reached termenal volocity of only 40 MPH. They thought that was good enought so they stuck with the c®itter for two years. Go figure.

If the above wabble happens again then for everyones safety, sell the car and get yourself a 41 SD coupe. End of problem unless you ignore regular maintenance like lube jobs, etc.

You're welcome,

Charlie

After ten tears with my 32 and a completely rebuilt steering system I also encountered the "death wobble". I adjusted all the tie rod and drag link ends and it cured the problem. And seeing it's been another ten years it's probably time to do it again rather than wait for the problem to re-appear.

Totally agree,

Charlie

"Sure fix. Slow the h..l down. Those ol' 37's and 38's weren't meant to travel over 35 MPH. The speedometer may indicator may suggest a higher speed but it won't go over 45 without something falling off and entering the "Death Wobble" zone."

I drove my stock '37 coupe from Rochester, NY to Wyoming and back, mostly on I-90, at or above the legal speed limit. Drove 3K-miles on that 2-week trip and never had a problem of any kind, including parts falling off ! Sure glad I didn't know it beforehand.

I agree with Bowtie Bob, back in the '60s and '70s when my '37 was my daily drive to work car, the speed limit in Iowa was 70 mph and that is what I drove it!

Uncle Ed and BB,

You may have entered the twilight zone. Seen any Yeties out on the wing of the airliner lately?

When we get older and our synopsis start to rust, we tend to remember things a bit on the fantsy side. Seventy mph couldn't be reached in a 37/38 with a long steep down-hill run with a tornado pushing the car east down an east-west road. You disremember. If you did manage to really think you saw the speedometer needle reach 70 mark you would have just woken up and had a bunch of crackling in your eyes. A believable explanation. 70! No way, Jesus! You both are just dreaming of what might have been but never was. Pity when reality and fiction get all scrambled up in the noggin ain't it.

Let the missus do all the driving from here on out. You'll swear she's doing a 100 mph on the straightaways but really only doing 35/40 which is as close to maximum sustainable speed for the ol' 37. While hanging your head out the passenger side door and enjoying the rush of air, keep your tounge in and close your mouth, Lots of bugs and neighbors out there. The bugs may be delicious but the neighbors may gossip. Wouldn't bother you none owing to your state of mind but might be rather embarrasing for her. You know. In church, on the street, quilting bees, barn dancing, rodeos, funerals, hog killings, canning, branding, corn shucking, etc. Mercy!

Best,

Charlie

You are dead wrong Charlie, I have seen my speedo well over 80 mph. I go on a charity cruise every year and cruise it at 60 mph for over 100 miles. The limit in Ia. is 55 mph now. The engine in a 37 is almost the same as the one in your 41 and my master has a 373 rear gear, not sure what yours is but probably a 410. Come on up to Iowa and I will race you!

I resent your insinuations, 41SpecialDeluxe.

My speedometer was checked against a GPS and is accurate within a couple of miles an hour. I have owned (2) '37 Chevys during the last 39-years and driven them on many tours, both with groups and alone, over that time and have been able to keep up and exceed traffic on all of them. I also have converted my cars to the 3.73 rear axle and changed the speedometer drive gear to read correctly.

I've drag raced, and hot rodded many cars in my youth and know what speed I'm driving at. Perhaps things might fall off YOUR car at higher speeds, but I asure you they never have on my mine, but then I maintain them.

Charlie has an ongoing goal to poke fun at 37 and 38's. I suspect it is actually his dream car since he is "stuck" with several 41's. I have to admit that Charlie's boasting about the 41's has gotten me to look closer at them and I find I do actually like them lol...

Back on topic...I am just starting full disassembly of my 38 chassis so am interested in this thread as I will be refreshing everything so curious what Rusty finds wrong...

I thought that a 37 had a 4:11 differential as does a 41. A 3:73 is cheating. Unless you have a lowly standard with leaf springs for the front. To lose to such a machine would be too embarrassing to live with.

I don't think I can outrun you. So, no to your challenge.

Best,

Charlie

BTW: I bet you're not running a regular 37 unmodified engine either.

The lower gearing in the 37 would be 4:22.

The '37 came with 4.22:1 gearing in the Master Deluxe and 373:1 in the Master model, which gives a considerable highr speed at the same engine RPM's. Surprised that you "KNEW" a '37 couldn't run at 70 mph without knowing that there were different axle ratios available, but then this is the internet where everyone can be an expert.........

My 1939 Mastter Deluxe with original 4.22 gears would cruise at 65 MPH and drove it to many meets and tours at that speed.
In about 2001 I installed the 3.73 gears and 70 MPH became my speed.
Gas mileage rose from about 15 MPG to 17 MPG.

With the 4.22 about 75 to 80 MPH top, 3.73 80 to 85 MPH.

The 1941 I had back in 1951 would run between 60 and 65 MPH, 82 about tops and gave 18 MPG at 60-65 MPH on on 3600 miles trip to Colorado.

BB, (another one. How many BBs are there?)

I agree completely with your statement about everyone being an expert. I sure got this one wrong so I ani't no expert but I'm not alone. (I had the parts manual right beside me but was too lazy to look up the information before opening my big mouth. That's never happened before.

Thanks for the correction to my post.

I apologize to Uncle Ed. I'm now convinced that that 37 of his is the fastest thing in Iowa. Is too! I can imagine seeing the dust trail rising up behind his 37 as he wheels and deals out there through the corn fields.

Best,

Charlie

BTW: This was taken out of the back windshield of his 37 as he is leaving for the grocery after having been told by the upset missus that he had forgotten the milk and bread again. See below.

I would have thought running a 216 with 4.11 or 4.22 geared rear end over 60 mph would be a little risky as far as the health of the engine is concerned. My '50 doesn't seem to care for it, nor did the '58 Chevy pickup I used to own with a 235. In fact I couldn't get more than 50 mph out of it on a downhill run with a good tail wind!