The lower shock mount 12555201 on my 73 Eldorado, is the one that threads into the final drive housing the same as the opposite side on the L/H swing arm, Parts manual is not very descriptive for this and do these have a history of breaking, I cant find much info about them , Im about to set off on a couple of thousand kilometre trip that involves a fair amount of Australian unsealed back roads and wondered if I should acquire a spare to take with me. Thanks Ray