Recently bought a reasonable-looking 1990 240 as interim drive to the temporarily retired 93 which needs a good rebuild. Started a proper service on it which revealed a neglected car with all sorts of hiddens horrors that was meant to be run on pennies and driven into the ground then sold off just before the end. There are some daft idiots in this world, you just don't do that to an old brick. Found silicone seal on both M47 filler and drain plugs which should have warned me. Managed to save the threads on the drain plug hole and got the drain plug out and leak tight again with two copper washers but the threads on the filler plug are all stripped. Has anyone attempted a good repair on this? Is the only worthwhile repair a helicoil insert and if yes, what size should I go for ? I need to repair this threaded filler plug hole in situ as I am off on a roundtrip soon and have no time to remove the gearbox. Is the gearbox under internal pressure as I was thinking of plugging the hole with a plastic or alloy plug as a stop gap measure or use a conical plug.
Any idea or suggestion of a good repair would be greatly appreciated, I already like this neglected old bus.
Oh, by the way, this car came with full Volvo main dealer service history ...
Thanks a lot for your help, guys
Goggiman