M135 Shimmy trouble

[Brad]

It has been some time since I have been here, but still having problems with my Dad's 1952 M135. Hope someone has an answer to this.
Suddenly last fall it developed a very bad shimmy at certain speeds. At times really violent. But we havn't been driving it much due to covid and all that.
But since Dad passed my Son has inherited the truck, and these problems, as he is the only grandchild that's been in the service.
Last fall it suddenly seemed to develop a severe shimmy at certain speeds? We have looked for loose tie rods, etc with no luck. Last night we switched a couple tires around moving a rear to the front and vice versa. No change??
We are at a stand still and have no idea what it could be??
Any advice would really be a help?? Ben says he has seen this problem listed before as Death Shimmy? New to me.
Thanks

 

[NDT]

Did you move BOTH tires on the front or just one? While you have tires jacked up, spin them and look for wobble or tread separations.

 

[M37keppy]

Check the king pin bearings on the top and bottom of the ball at the end of the axle. There should be a slight preload on them. TM should say how much. It’s adjustable by shims. I know on Jeep’s if they are to loose and worn out it can contribute to a death shimmy.

 

[Brad]

Only switched the drivers side wheel and tire. I will look at the manual regarding the king pins. But everything is so big and so heavy it's hard to tell if all is tight or just hard to move cause it's so heavy? Gotta try though.

 

[williamh]

It has been some time since I have been here, but still having problems with my Dad's 1952 M135. Hope someone has an answer to this.
Suddenly last fall it developed a very bad shimmy at certain speeds. At times really violent. But we havn't been driving it much due to covid and all that.
But since Dad passed my Son has inherited the truck, and these problems, as he is the only grandchild that's been in the service.
Last fall it suddenly seemed to develop a severe shimmy at certain speeds? We have looked for loose tie rods, etc with no luck. Last night we switched a couple tires around moving a rear to the front and vice versa. No change??
We are at a stand still and have no idea what it could be??
Any advice would really be a help?? Ben says he has seen this problem listed before as Death Shimmy? New to me.
Thanks

When I had my M135 it shook bad with too low of air pressure in the tires. Those poor excuse of shocks ( hydrolock dampers ) didn’t do crap , even when they had fluid in them , definitely get those tires checked if they are starting to desperate they will really shake the truck , also If they are bias ply tires they will “shake” the truck until they warm up , just my personal experance. . Good luck

 

[williamh]

When I had my M135 it shook bad with too low of air pressure in the tires. Those poor excuse of shocks ( hydrolock dampers ) didn’t do crap , even when they had fluid in them , definitely get those tires checked if they are starting to desperate they will really shake the truck , also If they are bias ply tires they will “shake” the truck until they warm up , just my personal experance. . Good luck

.

I really hate spell check

 

[CMPPhil]

Hi

I assume your M135 has 1100x20 nondrectional these tires take a set (as mentioned) when the trucks sit for any length of time. They will thump for a really long time until they get warm enough to get rid of the lump out. If the tire are old they may never get round again. As suggested jack up the front end and turn the tires to look for out of round and or wobble. Old school take a piece of chalk held on a block or wood so it just touches and turn the wheel.

Have you found a stretch of road the truck will wobble at a particular consistently? Is it flat, straight, heavily crowned?

Another cause I found for speed sensitive wobble is air pressure, with tires warm air the truck up to the listed and see if the wobble is worse or less. If the wobble goes away as air pressure goes up, it is likely uneven wear of the tire tread is the cause.

Cheers Phil

 

[Brad]

Friends, I appreciate all your replies. In answer to some of the questions, we only switched the driver side tire. Also, I will check the air pressure. We have always used just 55# per tire, but keeping them all even at that.
Yes they are the old military type tires. They appear decent condition. They have usually taken a time of running to get the flat spots smoothed. But they always do. This is not that, but a completely different wild wobble. It seems unsafe at that speed, I'd guess around 45 MPH.
Thanks again

 

[Brad]

Tow in wrong?
In looking this over closly today it appears to me that with the drivers side front wheel straight ahead that the passenger side is slightly turning to the right? I am thinking this could cause the wobble?
I checked the TM and it gave an approx. dimension of about 62 17/32", if I remember correctly cent to center. I measured best I could alone and come up about 3/16" short of that, which is in keeping with what I am seeing, I think.
Soon as I get some help I will try and adjust the toe-in. Should be about 1/4" or so wider at the rear.
Question is, could this be causing the shimmy??
Thanks

 

[dmetalmiki]

Google what causes a truck shimmy and death wobble.
You will find a plethora of information to go through.
Dodge Death Wobble: Causes and Cures

• March 25, 2019
• Story By Mike McGlothlin

 

[292FARMER]

PS Mag G749.pdf GO TO PAGE 17? TALKS ABOUT A SHIMMY ISSUE AND THE BOLTS TO CHECK...WORTH A SHOT

 

[G744]

There was an obscure MWO for the G749 trucks, entailing fabbing a steel brace that bolts on the bottoms of the front spring towers between both sides.

It looked like a two pieces of 1/2" flat, welded to a 1" dia steel bar. Hole in each piece of flat for the bolts.

I saw these on Guard trucks years ago, seems to work well.

Dennis

 

[Brad]

PS Mag G749.pdf GO TO PAGE 17? TALKS ABOUT A SHIMMY ISSUE AND THE BOLTS TO CHECK...WORTH A SHOT

Thanks, but I cannot get it to open?

 

[292FARMER]

Thanks, but I cannot get it to open?
PS – The Preventive Maintenance Monthly for the G749 | SteelSoldiers
TRY THAT LINK AND I COPIED THE PAGE, THERES IS MORE IN THAT PDF, BUT THAT ONE JUMOED TO MIND

 

[Brad]

I was able to doen load that. A lot of great information on ther, and things to look for and try.
Thanks

 

[Brad]

UPDATE.
Got to spend a few hours with my Son on this truck this afternoon.
First, It has that fabricated brace between the springs added.
We found a lot of play in the pitman arm so we adjusted it up snug plus a little. We do not have a scale to use per the TM. I will get something to use if I had to.
Also the gear box was low or maybe empty of oil. We added 90weight GO. Snugged it all uo, made all the tires 55# and too a ride.
Much better but at about 50 MPH it started again.
Went back and adjusted the end play on the worm gear per TM as best we could. Even removed the drag link and we had no detectable slop anywhere.
Took another ride and had no trouble till a little over 50MPH.
We are wondering if we are expecting too much and that it might be normal to get shimmy at 50MPH?? BUT, what is so frustrating is that we did not have this problem at all until sometime last summer or fall.
It had started that shimmy stuff and we were perplexed. We noticed it had a couple Broken studs on one front wheel so we replaced them, thinking that might have been the trouble. But not, made no difference.
We also checked the tow in best we could and it seems ok.
Will now check that better?
Man I sure would appreciate some help if anyone is in western Pa. Happy to pay.
Thanks

 

[NDT]

Truck should go 58 mph against the governor smooth as silk. I still think you have a tire coming apart inside.

 

[Brad]

I must have missed your earlier comment regarding a tire coming apart? But how could I find it? Would I just change the other front wheel? I already did the drivers side.
Thanks to all as always.

 

[lucydeuce]

not sure about bias tires but all the radial stuff i play with a seperation is usually a bulge. at the automotive shop we see it all the time. i chased a shimmy on a 300zx i own for a little while before taking a front tire off to roll it to the wheel balancer and it rolled a half a rotation then fell over from the massive bulge on the inside shoulder.

 

[williamh]

You could take the wheels down to almost any shop that does semi trucks and have them run them in the balancer. It may be a bad wheel or tire. When I had mine and had a bad tire that front end would “dance” almost pulling the wheel outa my hands. End end up replacing all the tires. All were old as crap but still looked good from the outside but were separating .

Look ma good spellin