Ok, i doing a brake job on a 380SL, and when i went ahead to install the brake disc assembly, i tightened the bearing nut. But unlike in the 420SEL, when i got it tight and the disc turned with great difficulty, and when i backed off the nut 1/4 of a turn, it was free. But on this, when i got to this point, the disc would have trouble turning, but after the first few degrees, it spins just fine. The bearings are fine, no discoloration or nicks, ditto for the spindles. I'm using the conventional way of servicing wheel bearings. Do i need to borrow a dial gauge to check bearing play? Do i need new bearings?