Try deleting your groups.cache, cigen.package, and accessory.cache files. Sometimes they get corrupted and cause your game to have problems loading. The game will automatically regenerate them when you start your game up again, so they're safe to delete.
They can be found in My Documents\EA Games\The Sims 2
i just tryed it and started the sims 2 up it still stoped loading at replaceing the wheel bearings.

T_T