I used to suck and blow on the distributor vac advance diaphragms to test them. My old '83 had a blow-through/suck-through one, and I found a simple junkyard replacement that didn't.

I've since gotten wise and have been taking my Mityvac to them. This time, the gauge showed a slower leak on my new to me '82. So I went to Rock Auto while also buying a replacement parking brake cable, while I was at it to save on shipping by buying several items.

They only sell whole distributors. That's fine, I may get one, but not right now. I just wondered if, since there are remanufactured whole distributors, if somewhere in the parts stream leading up to the remanufacture, there were just a couple vacuum advance diaphragms available by themselves.

I once did take apart the dual diphragm module fitted on these distributors just to see what was inside. I thought of how nice it would be if instead of being crimped together, they instead had a few bolts around the edges with a ring hold down and instead of a staked fastener in the middle of the arm that the diaphragm pulls on, another small nut. Then when they go bad, all you'd need would be a diaphragm gasket. I guess the whole planned obsolescence scheme is the reason it isn't that way. Cheaper to manufacture with the crimp fitting and melt the sun'bitch down, rubber and all when it goes bad into new steel. Whatever.

Anyways. VACUUM DIAPHRAGM ADVANCE UNITS!

 

I got one from LCE. But I think the price has gone up:

http://www.lceperformance.com/Distri...-p/1081123.htm

 

Looks like you tried to lift that fold too quickly, ya have to baby it. Think one could leave the lip up all the way around and glue in the trimmed water valve diaphrams, drill about 16 small holes for screws and nuts? might work... I had no problem folding it back and sealed well. Best for others is to buy new I think.