Help w/timing belt - bolt head issue on tensioner for timing belt

Not a good situation. New 12mm timing belt tensioner bolts are on backorder with Toyota.

Whoever did the timing belt before mangled the fan nuts Had to get new ones and went ahead and got a new fan clutch. The timing belt tensioner bolts weren't perfect but looked OK. However, my open wrench slipped and I'm afraid the heads are almost stripped. There wasn't enough room to get the ratchet end on.



I was finally able to get a socket on when I dropped down to a 3/8 inch socket. But it starts turning enough where it's hard to get the socket back off. Worried that continuing will strip the head


I've been soaking it with PB blaster. They seem tighter than the recommended torque setting Other than trying to file the edges, however I'm worried that's Just going to make it more loose on the corners and repeat the same problem

I know one option is to file it down and try to get an 11 mm on it but that also scares me

 

How about using an extractor socket?

 

Thanks I've honestly never used one but sounds like the best option

what made it worse was I was doing it from the top and I thought it broke loose. I couldn't see the wrench just turned.

 

That got it. thanks

I can see where my wrench slipped and made it worse, but you can tell from the older markings it was already in rough shape