Just when everything was going to plan...

I thought that things were going well tonight. I guessed (correctly) which wheel had the leaking brake cylinder, yanked the drum off, pulled the seals out, stuck new ones in, bled it some, and got reasonable pedal.

Then disaster struck. I decided to bleed the rear wheels to see if that got a better pedal. The bleed screw on the wheel I tried was stiff, but eventually undid. I pumped some fluid through, wedged the pedal down, and did the screw up, or rather tried to. The thread in the wheel cylinder stripped with almost no force on it. On taking the screw out I found the reason - the screw had rusted in the cylinder, and when it was undone, it had removed most of the thread from the cylinder. The little that remained had failed when I tried to tighten it all back up.

The scary thing about this is that had I been a fraction more gentle, the little bit of thread remaining might have held... until such time as I hit the brakes really hard - when it might have blown out, which would cause total brake failure. I would now advise anyone who finds they have a stiff bleed screw to remove and check it properly - just in case it too is partially stripped.