Why a Phillips screw head for this I'll never know. But apparently when my son last filled the shaft with grease he tighten the screw so much it cannot be unscrewed without stripping the head. What would you do?

Depends on if I was drinking....if I were, I'd beat the crap out my son ensuring he didn't do it again. Then I'd get a flat head screw driver and a hammer, and removed the stripped Phillips head screw.

Craig has a very good point and solution.... And you sure do blame alot of shit on your son.... Im guessing he is not the sharpes tool in the shed, or you fuck up alot of stuff and blame it on your kid.... Which one would it be????

Prolly what happened is it was screwed when it was cold and now that it's warmed up, the screw expanded and seized. Better explanation than my son's fault. He's actually brilliant, but has to put up with my bull.

get a pd we use allen heads lol

Put it on ice and see if it comes loose.

Beat the flat head in to the screw, then turn it. Coonass easy-out...

When you get it out replace it with a allen head screw

Left hand drill bit and an extractor.

Needle nosed vice grips & replace it with a allen head.

Did you try a hand impact? The kind that you hit with a hammer. Works great on the tight phillips screws on motorcycles.

If all else fails, Take a hacksaw are a dremel tool and make a slot to fit a flat head screw driver across the screw head. Then tap on it with the screw driver inserted and work it in and out (not just out). Also make sure you use the right size screw driver, you want it to fit the slot snuggly.

And replace it with a BUTTON head allen screw.

Got it out. My what a difference the right sized Phillips screwdriver makes. Looked for a hexed headed screw to replace. You'll need a 10 sized 32 machine threaded 3/8 inch screw. Very hard to fine. 1/2 inch is too long. A small o-ring is needed as well or use the old one. Get assortment at autozone.