Lee,

You can inspect the old/new tensioners by clamping them in a vice and deflecting them 30 degrees. Bad ones stay there...

If you look at the flats on the aluminum shaft of the old one, you will find that they are worn, and maybe also those on the steel adjusting bolt plate, but much less so. The problem is one small section on the shaft.

One trick that got me home and lasted quite a while is to reverse the order of the bolt plate and the spacer when you reinstall. (You might need to flip the plate over, but it is symmetrical.) Reversing the installation order will put the plate on an unworn section of the shaft. It will wear again, as that aluminum is a dumb choice of materials for the shaft, but this will give it a second life...

Gerry