How can you tell when the haft shafts need replacing, both of mine are out of the car and one will collapse and the other will not. And there is grease all over, Do the seals leak, can they be rebuilt?
Original Post
The half-shaft splines are only protected with a dust seal. You should be able to unscrew the seal collar with waterpump pliers. The two pieces should then pull apart pretty easily for cleaning & inspection of the internal splines. Sometimes, owners never grease the halfshaft splines, or drag-race their Panteras, and big sticky tires with repeated dumping of the clutch at high rpms will twist the internal splines in the half shafts, which then binds up the sliding action. The halves must slide in and out freely for proper operation of the rear suspension. Look very carefully-if there is lots of wear or twisted splines, both halves must be replaced- they are balenced as a pair and there is no economical fix. The good news is, there are lots of used half-shafts around at decent prices.