to reiterate the above posts about the half shafts. Changing the ride height or angle of the axle with a 30 year old boot which has become set in its ways definitely causes the rubber the crack and eventually leak. Ive done this both ways, overloading the trunk on a sedan, and doing exactly the same thing you did, trying to raise up the back end.

My reason was for towing, I put in new springs, heavy duty shocks, and the thickest spring pads I could find, with the result that in less than 5 thousand miles both boots on both axles cracked and leaked. I replaced them and it was fine for the rest of the time I owned that car, another 30-40 thousand miles.

You just needed some fresh rubber on those axles. This is really a warning though as you say, not because its a bad idea to change the ride height, just because it will cause failure of already ailing or old components, all you've done is given it its excuse to break.

Kind of like kicking the walker away from grandma and waiting for her to fall on her own.

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