I'm having one of those days :(

This concerns my 1980 Volvo DL (240 N/A) with about 143k miles (odometer broke). I read the FAQs carefully.

https://www.brickboard.com/FAQ/700-900/Cooling.htm

Questions:

It's hard to find water pump gaskets (my water pump is fine, just needed a new gasket and o-rings). I had a leak and tear with auto store-recommended gray (rubber-fiber). What's the best gasket material to use and to avoid?

Also, you're not supposed to reuse the water pump bolts, but I'm having trouble finding replacement bolts, absent buying a new water pump. It looks like the bolts are M6 maybe 30 mm and 8.8 strength. I'm reluctant to buy regular bolts at Home Depot. Can anyone confirm the specs and place to buy them and/or other components of 240s that I could get from junkyards?

Are B21F water pumps harder to install than B230F? This is my experience. I changed a water pump on my 1988 240DL in a couple of hours, start to finish. I spent nearly 12 hours just trying to install the water pump without leaks. I followed the FAQs carefully.

Here's what's going on.

According to brickboard FAQs (see link above), I'm supposed to install the water pump straight into the engine block, then loosely attach the two nuts on the right, then use a lever to push up the water pump while installing the bolts. I tried that at least 3 times only to get the water pump's upper o-ring to compress funny and to leak. I *think* that I solved the problem by putting one bolt on the top left in as a guide, then used a putty knife to flatten and align the o-ring. Thoughts about how to do this properly if the FAQs don't work?

The upper water pump o-ring was swollen and had oil over the top, indicative of a camshaft oil leak. When I removed the o-ring, it was not really swollen, but had cuts across the top. What caused that?