Hi Norm,
I've had this problem on old Victa 18's there's a few ways that will work but depends how bad it's stuck. I just cut the bolts with
a hacksaw the problem here is the bolts are low grade steel so a bit of force to undo them will snap them and hammering
mushrooms them making them impossible to remove.
You can heat the bolts underneath with the oxy ,once the nuts are removed , heat then spray with crc ,heat again spray with crc
a few goes of heating and spraying crc can work to loosen the corrosion and rust.( you want the lot upside down to do this)
If you hammer the bolts put a block of wood on them and hammer one at a time
You can't hammer them that much as mentioned before they will mushroom and makes them impossible to remove.
You can drill the bolts from underneath ,I mostly have drilled from the underside just so the top can't be damaged if the drill was to slip.
I would usually cut the bolts from underneath close to the base so there is less to drill.( bolt cutters and grinder usually work)
Some engine I've got 3 bolts to move but can't get the last one to move and have to drill it from underneath .
You can cut the bolts above the base or body then arc weld the nuts underneath the base to the bolts and then see if they will
undo with the rattle gun but best to undo by hand if you don't want them to brake and any movement you get , you keep slowly
tightening then loosening backwards then forwards with crc until they come out.
Only other way I've done it is to turn the lot upside down then with the nuts removed from the bolts put white Vinegar around the
threads , you can put paper towel around the threads this will keep them wet but you will need to keep putting a little vinegar
on the paper towel every day and could take 2 weeks to loosen.
The quickest way I think if it's completely stuck is cut the bolts on the top side wire brush the threads you can get to with a brush in
a drill then arc weld the nut on close to the underside of the base ,do one at a time ,try tightening and loosening to get it to move
but look on the other side make sure it's moving otherwise it will snap the bolt, If that doesn't work you have to drill them but if you drill
from the top sometimes you only drill half way and the nut that you welded will turn ,the weld gets the heat in as well, lots of crc.
Cheers
Max.
