Taylor:
Thanks, but I've bought both the RockAuto kit and the Crown kit from Summit Racing. Although both are listed as correct for a 1984 Eagle, neither one fit; they are both too small.
VanGremlin:
I had tried AMC LIves but not Kennedy American. I looked, and they have this listing for a MC:
clutch master cylinder- 3/4" (81 after eng#011C03) 3238493 $129.00
However, I know my cylinder is larger than 3/4", because that's the size of the o-ring thing in both of the rebuild kits I've bought, and I already know they are too small. I should have measured the bore on my cylinder while the mechanic had it torn apart, but he has already put it back together. Kennedy also lists a rebuild kit, but don't say what size it is. I will call them when they are back in the office Monday and try to get someone to measure the o-ring in their kit; if it's bigger than 3/4", there is a chance that it will fit my cylinder and I'll buy it.
For that matter, maybe the 3/4" MC they have in stock could be fitted to replace my larger MC... I just have no way of knowing. It just freaks me out that no vendors anywhere have ever heard of two different sizes for the MC, and it makes me reluctant to buy any more parts with no assurance that they will fit. I've already got a nice collection of worthless rebuild kits.
I went to car-parts.com (thanks for that tip!) and found a MC and reservoir from a 1982 Eagle for $125, but again, who knows if it will fit? It would cost me $125 to find out...
If the Kennedy rebuild kit doesn't pan out, I will have the car towed home. It was drivable (but flaky) when I took it to the mechanic, but he tore the original o-ring removing it, so now it's undrivable. Which really sucks, because I could have sold it and told the buyer it had a flaky clutch, but now I can't even demonstrate that the rest of the car is working.
Thanks to everyone for your ideas. I'll offer it for sale to Den members before I list it anywhere else, but you'll have to arrange transportation from Sugar Land, TX.
JB