55.2-59 Truck bed bouncing

[popeyestruck]

Took the truck out for a shakedown and the rear end is bouncing pretty bad. It rolls good while pushing it . Seems to be worse once the clutch is all the way out and not as bad with the clutch partially pushed in. Would an out of balance driveshaft be that noticeable? I didnt mark it when I took it off because I figured with new yoke and u joints it would be off. I rebuilt the rear end ,rear brakes , new shocks , rebuilt transmission. What might cause this?

[nvrdone]

It could be the driveshaft. it could be the drive shaft angle. It could be the rear axle shafts if you had them re drilled to a new bolt pattern. It could be a bad tire.
I would think you need to get it up on a lift and have some one run it in gear while you look it over.

[popeyestruck]

Thats todays plan . Looking at it closer all the grease has been forced out of one of the pins holding the leaf spring on. These are one of the few things I didnt replace. They were solid with old grease and I had to heat them to get grease in. Maybe the hardened grease was holding it together. Once the sun comes up i'll get a better look.

[dsraven]

one piece driveshaft or 2 piece? if 2 piece check to ensure it wasn't assembled out of phase, the ujonts on the 2 shafts need to line up. also check the slip yoke to ensure it isn't bottomed out. is it a stock driveline? if the engine has been swapped check the driveline angles at the front and rear. eg: if the engine is angled downward 3 deg, which is pretty common, then the rear axle should angle upward 3 deg so the ujoints will cancell each others speed changes as they rotate. does iy do this in all gears? just one gear? does it have shock absorbers installed?
if you have a helper you could try having a helper drive while you watch the rear axle, springs etc as the helper torques up the driveline. check to see if the springs are moving a bunch allowing the axle to wrap, do the tires/wheels have a nunch of runout, is the driveshaft running true, that kinda stuff.

[popeyestruck]

I figured it out rear tire is split. Thank for your help. I guess sitting around for 3 years took its toll.

[dsraven]

good to hear. now, check all the other tires or replace them. you don't want that to happen again at highway speed on a front tire.
if you don't know about the DOT numbers stamped on the tires then it would be good to google that and then check the DOT stamping on each tire. it will give you a production date. tires aren't made to last forever, more like 10 years max. they may have been new tires for you but they may have been sourced as older tires, like new old stock, for the tire shop you got them at. it happened to me with my boat trailer. the tires had lots of tread left and were about 6 or 7 years old since I bought them. one blew out at highway speed, tottaly wrecked the tire but fortunately no other damage. I checked the DOT on the remaing tires and there was quite a difference in how old each tire was, like many years between them even though they were bought as a set of 4. also, they were much older than the 6 or7 years since I had bought them

[popeyestruck]

I just went down and ordered a new set(4) they'll be in a couple days. I knew they were old but I figured they'd last long enough until I got it on the road and all straightened out. They looked fine until I drove on them then they just destroyed themselves. Sometimes it the simplest thing

[dsraven]

Good to hear it was just tires and you got it before a tire blew and did some damage. A buddy had a tire blow on his 6th wheel and it destroyed a bunch of stuff on the trailer. Like thousands of dollars damage.

[mr48chev]

Originally Posted by popeyestruck

I just went down and ordered a new set(4) they'll be in a couple days. I knew they were old but I figured they'd last long enough until I got it on the road and all straightened out. They looked fine until I drove on them then they just destroyed themselves. Sometimes it the simplest thing

Actually a very wise move on your part. I have known all too many guys in the past 55 years who the first week they get a project rig run out and tie up too much money in a set of wheels and tires before they even get serious about the rebuild and they sit there and age out and the trick of the week wheels get outdated by the time the rig ever hits the street. Having it sit on the rollers and waiting until "the day" was smart.

[popeyestruck]

Dont need to worry about getting paint and other stuff on them either

[popeyestruck]

Turns out them tires were new in 2004. When the put the bead breaker on them it went right thru the sidewall. The tire was fused to the rim.

[mr48chev]

The tires that my 48 is sitting on are from around 2000 and I wouldn't trust them for a 2.9 mile drive to the tire store. I'm not going to use the Enkie 32 wheels this time anyhow but the wheels I have for it have tires about the same age.

[dsraven]

popeye, you musta had the polyglass tires. heavy on the glass part, lol.
when I had my utility trailer tire lose the tread (right down to the steel cords all the way around) on the highway through the mountains (Roger's pass, Canada) in the middle of nowhere I had to install the old spare tire I had thrown in just to say I had a spare. well, the old spare was likely from the '80's. it was also just a car tire. I got it out and took a look. it was aired up but the sidewall was cracked deep. down to the cords. I had no choice so I put it on and drove real slow in to Golden BC. trailer loaded. found no tire in Golden on a sunday so kept driving and hoping. I made it the whole way, 3 hrs driving at normal speeds so with that old spare it took longer. I couldn't believe it.
needless to say the trailer now has a new spare tire and a new set of 10 ply's on the axle. nobody got hurt and no damage to anything. it was a win.
don't mean to encroach on your thread popeye. sorry.

[mr48chev]

The tires on the wheels that I am putting on my 48 look pretty good and didn't have a lot of miles but are over 20 years old. Not trust worthy except as rollers.



In truth I'd trust an old set of 16 inch bias tires with tubes and more cracks on the side walls than a mud field after a dry heat wave before I'd trust a 20 year old new looking radial.

[G&R's57GMC]

Speaking of old tires , these are from 2010 and still haven't gone any where .
The plan now is IF this chassie ever gets built and is ready to hit the road the first thing after driving it around the neighborhood is to do a massive burnout and loose the tread . Then get a new set of tires .
Or take it easy on them until the nubs wear off Then smoke them .

[dsraven]

Before you do a big burnout let a bunch of air out of the tires and check for anything weird in the sidewalls. It would suck to blow a tire apart while doing a burnout and have something damaged.