I don't think a 12” Brake drum could cause this much hop at 40mph. The rear hubs are
driven by the axle with the full floaters and they roll on their own bearings on a spindle
which is part of the axle housing. All of the has been indicated with very little run out
well within acceptable limits.
No she doesn’t dog walk and alignment is good. Also have had it up on sturdy jack stands
several and run it up to speed to check vibration with the tires off the road. Vibration is
definitely coming from the tires for some reason even though they run true and are in
balance.
As I said, speeds pre and post 40mph are fine, no hop and just the normal road noise and
vibration normal to a truck of this era with stiff leaf springs and beam axle. In fact if you
accelerate up thru 40 mph to 50 or 55mph you don’t even notice any hop or shudder.
Only manifests itself when you hold her at the speed.
Made the commitment and ordered eighty bucks worth of Dyna-Beads so we will see in a
week or two if they can work miracles. If we get snow I might have to wait till the spring
thaw to test them out.
I’ve always felt that this vibration was some sort of a harmonic that is set up in the
frame/suspension at that speed. Something like a speed wobble of a tire which you can
drive out of if you encounter it.
Dennis Graham
Sandwich, IL
Last edited by Denny Graham; 01/08/2012 4:48 PM.
