403 rear axle strap bolts

[Bristolian]

I fully agree with both Guymd and Stefan so add my view in support. I have seen this many times - my advice would be to continue with the remaining screws. Some many come out especially if you apply some heat using an electric paint stripper heat gun which is possibly the safest. Make sure you shield the petrol pipe feed which, I believe, runs along the nearside chassis rail. Those that break I would then drill out using good quality HSS drills or, better still, cobalt drills in a couple of size changes. You will no doubt damage some of the existing captive nuts internal threads (I think they are 1/4 whit dia) so could try retapping first to clear the threads. If this fails,the next step is to drill and tap these out using a metric size possibly 8mm dia tapping drill size .250" (1/4) tap 8mm dia x 1.25 pitch. I suggest this as the pan head screws are probably easier to get. The alternative would be imperial 5/16" dia whit 18 TPI tapping drill 1/4 (.250). This is by far the cheapest alternative to cutting out and rewelding which would be my last resort.
PS. All drills and taps are available from Tracy Tools, Devon. Best of luck - you will prevail. You can also contact me on Pegasus@...........org.