The Feb. '07 issue of Mopar Action Magazine has a "Tech Topic" letter regarding replacement calipers for cars and trucks. The writer has an '88 Diplomat which has a brake caliper leak at the sealing washers, where the hoses go into the caliper.
According to Rick Ehrenberg, washers supplied with calipers these days are often times less than 1/2 the thickness of washers we saw even a few years ago. This is due to higher commodities costs (copper and some other metals are in high demand these days), and the fact the newer washers are made in China. The old thickness was .057", versus .022" for the newer washers. These washers have to compress a little when tightened, in order to provide a good seal.
Thus we have issues with sealing when replacing calipers. Ehrenberg recommends Mopar P/N 6030084, and there are two washers per caliper. I would imagine these washers are also available in the aftermarket, perhaps in the "Help!" section (or a similar line) of the local auto parts store.
Also, Ehrenberg covers newer brake fluids versus older ones. Basically, DOT 4 and DOT 5 work fine in Mopars, and most older cars (going back to the earliest days of hydraulic brakes) will have better performing brake systems when properly flushed and filled with the newer stuff. Only owners of 60's GM vehicles need to be concerned, due to a port in the master cyl. having a problem with the slightly higher viscosity of the newer stuff.
The newer stuff is corrosion resistant, will not harm your car's finish, and has a super high boiling point. Also, steel piston calipers no longer freeze in place due to corrosion, when the newer stuff is used.