I don't believe the OP said whether BOTH tires on the axle had the same wear pattern. A toe problem will cause the mirror image wear on the other side of the car. Toe out will wear the inside edges of both tires, while toe in will wear the outside edges. since the OP thought he has a negative camber problem, I assume the wear is on the inside of the tire. If it is on the inside of both tires on the axle, a toe problem is a real possibility.

Camber is easy to check with a 2' level. When on level ground, see if the wheel is standing near plumb. You will probably need a couple of small identical blocks on the rim edge so the level can clear the tire bulge.

Worn lower ball joints can cause both negative camber and toe problems on front wheels. If your steering rack is behind the axle the toe problem would be a toe out problem which would wear the insides of both front tires. Ball joints are checked by jacking the wheel up using the front jack point, behind the wheel to be checked. Grab the wheel at 12 and 6 o clock and push in and out to see if there is any play in the ball joint, or either ball joint, if you also have upper ball joints.

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'97 E 300 D