could be wheel bearings, but check the springs well, something worn [from neglect of greasing times past] can allow the spring to shift a bit on one end and have similar symptoms

Bill


Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics