My wifes car has still got its original axle shafts, with both sides rebooted a few times. They run quiet, even when driven hard on full lock - the standard rough and ready test for a bad cv joint. The car (and the axles) has a quarter of a million miles behind it. I hadn't necessarily spotted a leaking boot straight away, maybe as much as a month possibly, and the car has been used as a cab for nearly all its life.
In fact I've only had one car with noisy cv boots out of maybe 15 fwd cars I have owned, and I drove that for about 8000 miles before I scrapped it due to rust. The conclusion I draw from this is that cv joints have a massive safety margin built into them.
Way back in 1966 a British consumer magazine deliberately tested some to destruction, they had to clean out all the grease and repack the boots with abrasives added to shorten their lives.
They tested 4 cars, in every case it was immediately apparent something was very wrong, from knocking noises, stiff steering, to severe vibrations. When the joints did fail typically after 150 miles or so, it had no adverse effects on the cars steering or braking, the car simply lost drive and rolled to a stop.
So replace your torn boots, repack with proper cv grease, and stop worrying.
Claud.
