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@GomerP , regardless the cause of the damage, there's a pretty simple way to prevent this if you have adjustable spring plates.
Just wedge a bolt with a half-inch head as shown in this photo before hoisting the car (one bolt on each side). This limits travel of the spring plates, and so, the axles and boots.
If I had to guess, I'd say your axle boots were already old and dried out when you lifted the car.
This trick was shown to me by an old, wizened, VW mechanic who does this every time he lifts a swing axle car. He's probably had to replace a few boots on his own dime after being blamed for the damage ("They were fine before you worked on my brakes.").
A note of caution: The bolts tend to get jammed when you lower the car, requiring some bouncing up and down on the suspension to free them.
Cheers!
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