you sir, just made my day

I cut the old idler pulley off, and removed the bolt with vice grips. I then drilled the threaded hole in the bracket for clearance for a 3/8" (? I think?) bolt. I put a washer under the head of the bolt that contacted the pulley hub (doesn't rotate) but did not contact the rotating part of the pulley. I put double nuts on the threaded end of the bolt at the backside of the hole I drilled in the bracket. Had to remove the bracket from the engine to get room to do all this, but that is easy to do.

well, I cut the pulley off. couldn't get a real good grip with the vise grips so I cut the bearing off. got the vise on would not turn, applied heat, would not turn.

cut a notch in the head, applied heat pounded with tiny sledge and chisel.

busted out the air chisel, applied heat. when all the dust settled the bolt remains intact.
only thing I can figure is the pulley was already replaced and they used thread locker.

I give up, I'm buying a new tensioner from rock auto
anything special I should know about replacing the tensioner?

pictures of the bolt that beat me ImageShack(TM) slideshow

A while back I had a bolt brake off in a tensioner. Remove it, put it in a vise. And drill out from the back side. Many times the bit will grab and spin the bolt right out. If not, drill all the way threw and use a easy out to remove it.

I agree with Danthurs. Center punch it and drill it out. Don't worry about cutting into the threads because you are going to drill the hole to a clearance for a bolt anyway.

Any parts store should have the assembly, or be able to get one in a day or so. Rockauto.com is also a good choice.

in my attempt to drill I cracked the housing, probably weakened it with all the heat I applied the day before. Then I went to our city'* only pick & pull no motors in the GM'* that were once supercharged..but did find some needed interior things for my Expedition.

finally pulled some strings at CQ and got the employee discount on a new tensioner at $51. all is good.
I have my angry Asian man sound back under my hood where it belongs

thanks for all your help fellas bs2

Glad to help. That'* what we are here for. $51 for a new tensioner is an excellent price. At that price you were better off than just changing the pulley.

Angry Asian man sound??? Never heard it described that way, but somehow it seems to fit.

Good to hear. Guess I have no reason to drive up there to walk around your pick and pull yard.