The Stovebolt Site Forums The Shop Area General Truck Talk Back to the vibration problem

Several months ago I got my '53 3/4 ton fired up after a restoration. The first time I took it out, it was for a drive of just a couple of blocks. No vibration on that short trip. Several weeks later, I took it out for the second time. After a very short time (a block or two), I noticed a vibration at slow speed. Turned around and headed home. Vibration was worse by the time I got there. After advice from a previous post, I pulled the driveline today and checked for being in phase. It was out slightly, so I brought it into phase and took it out again. Still the same bad vibration at slow speed. The truck has all new tired and the wheels were balanced at the same time. I double-checked the motor mounts for tightness. I'm not seeing anything loose. It doesn't vibrate in neutral even revving. it is only under power. I have not tried increasing the speed to see if a faster speed ends the vibration because I'm afraid to do it. The vibration is significant at slow speed. It also has new u-joints and with it jacked up and in gear, I see no vibration in the driveline.

Can you feel the vibration in the steering??? if so I'd check the tierod ends and the drag link...

mayby the tires have flat spots from setting

That is an excellent point. Do you get a vibration when you're sitting still with the engine running? If you only get it when rolling your problem my not be drive line related. Bias ply tires flat spot when sitting & it's worse in cold weather.

Okey dokey Rick, here we go. Ya gotta tell us what kind of tires ya got on there. If they are bias plies then that's your problem. I went all through this with my 1950, 3604 and there was a rather lengthy thread posted on the forum last fall.
I had 15" split rims that were in very nice condition, blasted and repainted with PPG two part taint. Mounted up 7.00x15LT Power King tires, tubes and flaps all were new and balanced them at three different dealers. The last one used the latest equipment that puts a load on the tire when they spin it up. New gas shocks all round and the front end completely, totally rebuilt and in it’s original configuration.
When I would start off in the morning the front clip looked like it was going to jump right off the frame. It took a bout five or ten miles of driving to round out the tires. If I parked it for a half hour while I ran into the Jewel I had the same problem till I was a few miles down the road. I tried tire pressures from 65psi down to 25psi, I tried putting a half-ton of sand bags in the back to see if some weight would help, NG.
In the end I finally threw in the towel and got a set of tubeless 16.5” rims and a new set of Cooper radials, vibration gone!
I still get a little cyclic shudder at around 45mph but I attribute that to the frames natural resonance and I think the only way to get rid of that is to box the frame between the cab and the box, where it is the weakest. This shudder is not there before 45mph nor after and it was also present with original tires, and the new bias plies at the same speed.
If you want avoid a lot of headaches and get over this 3/4 ton hurdle, call The Wheel Smith or Stockton Wheel, on Monday and have them make up four 15” wheels with the proper center and offset and you will be money ahead and ready for the summer driving season. Talked to literally hundreds of people that have been through this with the 3600 and that’s my conclusion.
Denny Graham
Sandwich, IL

had same problem years back with flatspots,but on a passenger car. they would round out at about 2 miles.

Denny, this is NOT what I wanted to hear. I've got about $600 invested in brand new tires for this truck. But, after reading your post, I am inclined to think you are on the right track. My local Les Schwab dealer installed new Nanco Super Highway tires. These are 8P.R. Load Range D tubeless 105/101L 700-15LT tires. First off, I didn't think tubeless tires were supposed to be used withy tubes, but they are also also new tubes and flats and the original two-piece wheels. I tried for some time to get something that would clear the front workings behind the rims, but no one could come up with anything. So I guess the next question is, does anyone see significant problems if I try to increase the speed and drive though this? I would really like to be sure the tires and wheels are the issue before dumping $600 and investing a bunch more into this. Also, would it make sense that I would not have had the vibration the first time I took it for a spin and now have it? The tires have been on the ground for about 6 months is all.

I thought about this a little more and if I'm understanding the issue correctly, I could keep the tires I bought and maybe even run them tubeless since they are tubeless tires to begin with. That's if I change the wheels out to Stockton. Am I right about this? I'm trying to get a feel for exactly what the problem would be if it turns out to be the wheels. Is it the wheels themselves or the tires and tubes I bought?

Tubeless- - - - -no way! Your split-rim wheels are not airtight without the tubes and flaps, so there's no option but to run tubes, other than swapping to a drop-center wheel, and those won't clear your brake drums unless you go to a larger-size tire like a 16.5" tubeless.

Just drive the thing! After about 5 miles at normal highway speed, or as fast as the shake will allow, the flat spots will warm up and go away. My son's Dodge-chassis motorhome with 16" tube type tires does the same thing, rattles teeth for the first 5 to 10 miles, depending on temperature and how long it's been parked, and smooths out after that. If the tires happen to have nylon cord, it's worse, the dreaded "nylon thump" that all commercial-rated tires used to have.
Jerry

Bias belted tires take longer to "round out" in the cold weather. Funny how the entire planet put up with this nuisance all those years.

Well guys, I took the truck out and ran it up a little in speed. It evened out a little and wasn't vibrating as bad. By the way, it still vibrated with the clutch depressed (that was a question someone had asked). I'm thinking a combination of the tires and the driveline that I put in phase yesterday may be the issue. I noticed that the accelerator is sticking a little and I have to hit it with my foot to get the rpm's to back off. Oil pressure and temp are doing fine. Quite a bit of blue smoke on start-up and until I got it out on the road. I guess that's probably normal since the engine is rebuilt and only right now has maybe 5 miles in it. The engine runs a little rough. I had a mechanic friend time it for me when we started it up, so it probably needs a little further adjustment. I have sdome other issues such as hood alignment as it wants to keep popping open on me. Doors are rattling since I don't have the weatherstripping in yet. No door glass either for that matter. It has to be floorboarded to get close to 55, but I remember that from back before. Still alot of odds and ends to fine tune, but it'll get there. It snowed here this morning (we aren't supposed to have snow), but the roads are clear and just wet, so I'm sure the tires didn't warm up much on this short jaunt. At any rate, I feel a little better knowing I can run up the speed and it evens out a little on the vibration. Thanks for all of the posts and the recommendations gentlemen.

have you checked the driveshaft balance? mighta dropped a weight

Bill

Hey Jerry I think Rick was talking bout just getting a new set of rims and remounting the tubeless tires he has on them. That would be a real nice set up Rick and you could use the tubes for the kids when you go to the beach.

My problem was that I live about a mile from town and when I would pull out of the garage I couldn't get over 25 or 30 and it was real embarrassing with the front end shaking like all get out. I found that I could drive thru the vibration so if I headed the other way, out to the country and ran it up to 40 for 8 or 10 miles then I could drive back into town with my head held high.

I just talked with one of the local guys who contacted Stockton Wheel and they are building him a set of wheels for his 3604 AD. I believe he said $125 each and then the shipping.

I used 16.5" wheels, from a junkyard, $50 plus blasting plus PPG DBU that was another $100. I have limited choice of tire sizes and had to spend close to $300 for front spacer/adaptors to clear the tie rods. But I can use the stock hubcaps and the wheel spokes look like the original!!!! Take a look: http://rides.webshots.com/photo/2513755820098611668CgdlbK

Denny Graham
Sandwich, IL

The 16.5s are prone to vibration & shaking. It is hard to get the tires centered on the rims.

Wow Denny, that one heckuva spacer, did a local machine shop make those up for you? The truck looks pretty good though and I bet the ride is just right.

Birge

Nope Birge, those are from a manufacturer in California. The ride is about as good as your gonna get with a 1950 3/4 ton truck.
Denny Graham

I see you said you are flooring it to get to 55 mph. Is that a good idea to go full throttle with only 5 miles on rebuilt engine? Just curious.
Jeff

Hate to put a damper on these bias-ply tire comments but I just put a set of Firestone 650-16 on my 49 and they are as smooth as can be. Even after sitting overnight the are not flat spotted.
Old bias-ply were made with a lot of nylon, the new ones are not.
My old bias ply tires bumped when cold and had a vibration at about 45 mph. After putting on the new ones I figured there may have been something broken in the old tire casings.
Would I put bias-ply on a stock old vehicle again. Definitely.