What could cause this?

AT THE END OF THE SUMMER I COULD SOMETIMES HEAR A WOOP WOOP RUBBING NOISE FROM THE BACK RIGHT WHEEL AREA.  ONCE IT WAS LOUD SOMETIMES NO SOUND AND OTHER TIMES FAINT.

WHEN I PUT THE VETTE ON A LIFT FOR A GREASE JOB AND TURNED THE LEFT REAR WHEEL--THE RIGHT WHEEL WOULD HOP UP ABOUT ONE AND A HALF INCHES EACH TURN.  NEITHER I NOR MY MECHANIC (SEMI-RETIRED IN HIS 60'S BUT REALLY KNOWS OLD CARS AND IS VERY DETAIL ORIENTED) COULD READILY SEE WHAT CAUSED THIS.

ANY SUGGESTIONS ON WHERE TO LOOK OR WHAT TO LOOK FOR.

THANKS IN ADVANCE FOR ANY HELP

DICK

Pull the halfshaft off on that side and check the u-joints for binding.

Then grab the wheel and try to move it side to side and up and down.

You will should be able to find out the problem.

If the wheel bearing is bad, have both sides redone. And if the u-joints are bad, just redo all of them.

Good luck and let us know what you find.

Sarge

 

If the wheel is actually moving up (vertically) 1-1/2 inches, then I would bet it is the u-joints on the half shaft. If so, I would change all of the u-joints. Also look for any broken supension members and loose fastners. That is a heap of movement just to be rotating the wheel.

Good luck,

Scott

I had the same sound coming from mine before I rebuilt my rear suspension.  I replaced the bearings and u-joints and the sound was gone.  Sorry I can't pin point it to exactly which one it was for you though!

That kind of movement, my money's on the U joint

Usually if it a u-joint one way to tell is take the car for a short drive.  Maybe a couple of miles.  Bring it back and park it, get under and check the tempature on the u-joint crosses on the side that has the movement.  If the joint is going bad, that cross will be considerably warmer than the good one.

If you turn the wheels(rear) with them "hanging", as on a lift, the u-joints will "bind" as you turn them. This will explain the "hop" as you turned the wheel. If the alignment is off(camber), you could have more "bind" one one side than the other, because the u-joints are the upper links in the suspension. Always check u-joints with the car on the ground, or on a drive-on lift, for this reason.(or take the axles off, like Sarge says)
A "whoop-whoop" noise could be a u-joint, or a bearing on the way out. Does it make this noise only turning, going straight, or it don't matter