Seized seat rail bolt, help!

Ok, so one of my sub strap belt buckles popped out of the eyelet because I was stupid and forgot to put a cotter pin in place.

I tried to get the buckle back on with the seat in place, but just couldn't get it. So, its easy to remove the seat, only 4 6mm allen bolts.

Three bolts come out no sweat, the fourth bolt is turning out, but very slowly. I take care not to strip it, but it does anyways. So I cut a slot in the bolt head and tried to turn it out with my 18" long screwdriver. Nope. Putting an adjustable wrench on the screwdriver I could turn it just a little bit.

I don't have a socket that's the proper size to fit over the end of the screwdriver. I tried using a hammer and my screwdriver blade to turn the bolt out. No go. I figure I have it half way out now, maybe another 5 threads to go?

Any suggestions? Unless I remove the entire seat with seat plates from the car, then remove the seat/side plates off the bottom plates there's no way for me to get heat on it....

Since it looks like its into aluminum, you are gonna bugger up the threads and need to helicoil them anyway when this is all done - so - pull it apart, weld a hex nut onto the end of the allen, pull out your muffed up fastener, fix the threads in the aluminum, and reassemble.

Other option is to get a large screwdriver bit that goes onto your ratchet and use that,

First get some anti-seize/liquid wrench on the threads and try to turn it back and forth a bit to work it in, to maximize your chances of getting this out.

Honestly this sounds a lot like the last bolt I broke the head off of, which was crossthreaded by a mechanic using a too-big socket wrench.

Yup, those base plates are aluminum. I'm not too concerned with them, I can retap the threads in that hole, or just move the entire sliders up or down one hole if I can't retap them.

Bolt doesn't really turn at all right now, so I'm not going to be able to work penetrant in, although I can certainly hit it with some PB Blaster and let it soak.

Do you have a good old fashioned hammer strike impact driver? And if you do, can you get it on there? I've had good luck in the last year using this more and more on stuck screws.

Looks like you've got enough access to drill the head off the shank. Then with the seat out of the way you should have enough space to weld something to the shank, or use a chisel or vice grips to remove it .

If you can fit a drill in there, go buy a left hand drill bit (Fastenal, Granger, Mc Master Carr, Etc...) and drill it out. Either the bit will bore the head off that bolt, or it will grab and spin it right out of there.

Good socket head cap screws are hard enough I'm not sure a HSS drill will get through one easily. I'd go with mazdeuce's suggestion of the impact driver (a handy tool if you don't have one already), or just try hitting it with a hammer directly.

In reply to BrokenYugo:

Looking at how it's started to round out and the fact that he's already been able to cut a slot in it, I don't think it's an overly high quality cap screw. But yes, an impact driver would definately be worth a go if it proved to be to hard to drill.

Well, I cut the slot with my dremel and a reinforced cutting disc. That would've taken me forever to do with a hack saw. Pretty sure its a grade 8 bolt.

I don't have great straight on access to it from above, the seat is just in the way of me getting on it properly with a drill bit.

Also complicating matters is I don't have a welder and don't know how to weld.

I got my screwdriver on it and was beating on it with a 4 lb hand sledge to turn it out more and got nothing.

I need to buy an impact driver that MazDeuce suggests, then I suppose my next go is to cut/drill out the head of the bolt so I can move the seat out of the way.

I'm a little wary of that tho, as in my main line of work its a whole lot easier to remove a tooth if I have the entire tooth to play with leverage wise...

Is there enough clearance to cut the head off of the Allen Bolt then just thread a nut onto what's left?

The screwdriver takes up a lot of shock, hit it directly with a smallish ball peen hammer, then put a screwdriver on it.

What about one of them there new fangled air chisel setups? Like for taking rotor retaining bolts out. What they're called escapes me at the moment. Might be just the ticket. A shake and break! That's what it's called!

In reply to sesto elemento:

If you're really good and/or have an air hammer that can be turned way down (CP714 is my favorite) you might be able to catch the slot with a normal chisel bit and walk it out that way.

Gonna pick up an impact driver and see how that works...