Undoing bolts

[Tapitha]

Nice sunny day but cold so I decided to fit new seat belts. No problem unscrewing the floor bolts and the ones under the windows but failed to unscrew the lower ones in the lower sides. They seemed to be very solidly screwed in and rusty. The thin bolt head prevented me from getting a good purchase with ring spanner or socket. Any ideas as to how to get them unscrewed without snapping the bolt or rounding the corners of the hexagon!
Thanks,
Mike

[beero]

I assume the bolt threads are hidden in a cavity in the sill area. You could drill a hole to allow you to spray some plusgas on the threads and then fill the hole with a rubber grommet.

[bmcecosse]

Good hard clout with a hammer to shake up the threads.... plus heat and release oil.

[mike.perry]

How about a photo of the location of the bolts?

[drivewasher]

Impact gun is the only way. Get bolt out a little spray plusgas on exposed thread then drive bolt back in. Keep repeating this you'll get it further out every time. If you use a long bar you'll just snap the bolt or rip the welded threaded nut part out of the cill steel

[aupickup]

or try tightening a tad to free the rust then undo

[Tapitha]

Thanks for the advice. I have had WD40 and some release fluid on the bolt for a few days. Had another go at unscrewing this afternoon trying some of your suggested tricks. The passenger side bolt came out but no luck on the drivers side. The problem really I think is that the corners of the hexagon are rounded off (not originally by me but I have probably made it worse!). I cannot get a Stilson wrench on it as there is not enough space because of the metal end of the old seat belt being in the way. When the car was restored in 2004 I think the old seat belt bolts were reused with the original 1969 belts and not replaced by new so I expect they already had some rust. There seems to be some kind of natural law that says all screws and bolts can be undone EXCEPT for one (usually the last!). This is the third time I have had this experience doing work on Tapitha.
Cheers,
Mike

[Tapitha]

Still failed to undo the seat belt bolt. Tapitha went for MOT yesterday and failed surprisingly needing lots of welding here and there near rear spring hangers and offside door hinge pillar. Also to my surprise the handbrake failed although I know everything is OK with the cylinders and shoes. The examiner came up with a solution for removng the seat belt bolt. While doing welding next week they will weld a large nut to the head of the bolt so a better grip can be obtained. They did try spanners etc. but like me he failed. Cost for work to get MOT cert looks as if it will be about £500. Anyway Tapitha is worth the expense. Car repairs for safety ought to be on the lower rate of VAT.
Cheers,
Mike[frame][/frame]

[bmcecosse]

Goodluck with the weld repairs - hope it's not just 'cover patches' to scrape through an MOT for another year....... The handbrake should be able to lock the rear wheels on a dry road at 20 mph.... The cables need to be free moving - the cylinders need to be able to slide in the backplates and of course both halves of the pistons must be free... And the shoes must be oil free of course!