Big celebration here; we finally got them out. All 8 of them and not a single breakage. I think I have discovered the secret:
1. Trick - take your time. My bolts had been in for at least 25 years and it has taken me 2 weeks to get them out. Not 2 weeks of total work but a little bit every day.
2. I think the magic formula was a concoction of 50% brake fluid and 50% cellulose thinners. Brush this on twice a day. Mine came out after 3 days of this.
3. Don't be afraid to do some impact driving. I had hex bolts holding my exhaust in and it took me a while to find the right combination of driver bits and 3/8th inch and 1/2 inch converters. Give them a good whack. Do it a couple of times a day. Keep adding concoction.
4. Don't stick on the one bolt, try them all. I spent the first week on one bolt. Nothing moved. Then today I tried another bolt on the other side of the engine. It came out quite easily. So I did some of the others. The first bolt was the worst. See the photos and you understand why. I had spent all that time being put off because the first bolt I tried was the worst.
5. Take your time. Don't expect to do it in a day.
6. My next trick was going to be the blow torch (I ordered them from Ebay but they have'nt arrived yet) but in the end they weren't needed.
7. Trick - try tightening them as well as unscrewing them. My first discernable movement on the first bolt I got out was when I screwed it in. Even the smallest movement is good. Add more concoction and keeping screwing it up (until it's very tight) and then unscrewing it a little. For a time it seemed to me that it got tighter the more I unscrewed it. That was the sign to screw it back in and add some more concoction and wait a little.
8. From the photos you can see that the concoction penetrated the bolts by about 50% (see the darker part of the bolt) which is quite amazing.
