Don't bother removing the loader, but place the gounding clamp as close to the welding area as possible has worked for me. But, Jrli's advice is probably safer.
Yes as Oakie said. Never let your ground path for the welder go thru a bearing. It can ruin the bearing by burning places on the rollers/balls/races. Damage may not be immediately apparent, but get into your billfold in the near future.