I have an issue I can't seem to shake.
My 85 BRAT vibrates when I drive over 45 mph like clockwork. The vibration sounds like a low, constant rumble. And I can feel it on my back. The vibration seems to ease a little when I let go of the accelerator (above 45 mph), but it does not go away. It then eases again when I make it past 70 mph, but doesn't go away entirely.
I have brand new u-joints in the drive shaft (it clicked as I moved) and the vibration was there before and after I changed them. It also has brand new inner & outer tie rods, ball joints, front wheel bearings, front axles, shocks in the rear, front rotors, rear brake shoes. I had a tire alignment (needed to anyways after the tie rod change) and even though my tires have maybe 1,700 miles on them, I rotated the tires and balanced them anyways, but the vibration stayed the same.
Other than the rear axles, which for the life of me I can't find at all, new, used refurbished or any at all. I can't figure out what could be the cause.
I keep seeing almost everything pointing to either the tires or the axles, but with no new rear axles to be found and tires already rotated/balanced, I'm out of ideas.
Any and all help is appreciated!