[AT] OT truck tires/driveshaft?

[jtchall at nc.rr.com]

And the verdict is in, after over a year, it was the new, properly balanced, 
front tires. To those of you who remember this thread my grain truck had a 
horrible vibration, especially when loaded. I shuffled tires around on the 
back like crazy because they were old, mismatched and downright dangerous 
looking. Finally put a new set on the rear. I also put new shocks on the 
front. Studied driveshaft phasing and checked the truck. Jacked up one side 
of the rear so I could watch the driveshaft turn. It didn't matter what I 
checked, everything seemed OK. I was going to pull the driveshaft and have 
it balanced--would cost a little under $200 to do that. Dad convinced me to 
first put 2 old tires on the front that I had mounted for spares. Amazingly, 
those ancient, worn, mismatched tires got rid of the vibration. Put my new, 
balanced tires back on and it was back. I found a nice matched pair off a 
church bus on Craigslist, for less than I paid for one new tire. The dealer 
that sold me the tires switched them for free, the tire manufacturer would 
not give any refund. We hauled 8 loads of corn and everything seems to be 
working well. The only thing I can figure is a belt or something in the new 
tires was broke/breaking and the problem was steadily worsening. Anyway, I'm 
glad that is fixed, I was getting to the point I could swap those tires at a 
rate that a Nascar pit crew would call admirable!

John Hall

-----Original Message----- 
From: jtchall at nc.rr.com
Sent: Sunday, May 11, 2014 5:29 PM
To: Antique tractor email discussion group
Subject: [AT] OT truck tires/driveshaft?

Been a little quiet so I’ll throw a problem out looking for suggestions. Got 
a 74 Ford F-600 2 ton grain truck. Around 40 mph I get a BAD vibration 
(empty or loaded) It goes away around 50 or so. I put new tires on the front 
a couple years ago and moved one of the old ones to the back. Shortly 
thereafter we noticed the vibration. It seems to be getting worse. I had the 
front tires balanced last fall, didn’t help. I shuffled tires around on the 
back yesterday, can’t really improve the situation. I even tried driving 
with only the inside tire mounted, maybe some better, but not much. The back 
tires are not a matched set and are pretty old. I know it could use a set of 
tires but I’m trying to hold off a little while longer buying them. I jacked 
the truck up so I could look for runout and wobble. Some of the tires have 
wobble, some have runout on the diameter. One is perfect, but it is so far 
out of balance that with the truck in neutral, it settles to the same place 
every time—I even replaced this with a spare, still haven’t solved the 
problem. Would a set of new tires solve my problem or are big old trucks 
like this forgiving enough that I have other trouble? All the u-joints feel 
tight and I only notice a faint bit of runout on the driveshaft. An old 
timer told me he thinks I have a u-joint trying to lock up or a twisted 
driveshaft. Dad says they once twisted a driveshaft on a truck we had by 
popping the clutch when it started rolling backwards. Whats your opinion?

John Hall
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