M5OD frozen fill bolt

[RangerX]

Went to check fluid on my 94 B4000 and find I can’t turn the fill bolt. I used a 15/16” socket and a lot of force, and started to bend the faces of the bolt head so I quit. This is a new to me truck so it wasn’t me that overtightened it. Or maybe it’s rusted in?
What’s my options? Can something be tack welded to it to get a better grip on it?

 

[Brian1]

I rounded off a fill plug on my m5od because it was stuck. It took a few tries but I welded a nut to it and finally got it off. Putting heat into the plug helps to free it up. It also should take a metric socket but I don't recall the size offhand.

 

[RangerX]

Thanks Brian. My metric only go up to 19mm, not big enough.
I thought about heating it up, maybe I’ll try that before I go bug my neighbor to try welding a nut onto it. What was the difficulty in welding onto it?

 

[Brian1]

What was the difficulty in welding onto it?

There isnt much space to get the welding gun in there to get a straight shot and laying on my back under the Explorer trying to do it as well. If it was up on a lift it would probably be a little easier.

 

[RangerX]

To follow up on this, I left it alone for a month, and finally got the bolt out today.
I just got an air compressor again, so I broke out my old old Harbor Freight impact with a six point socket, swivel, and extension and, no go. Borrowed my neighbors HF Earthquake air impact and that did the trick!
Bolt head is not in the best shape, but should work fine from now on with just a socket and ratchet, since it only needs to be snug tight.