Jack up the wheels and spin them while watching if they wobble. If they do, look at the installation of the drums. If they are not centered on the studs, they won't sit flat against the hub surface.
There is an access hole in the hub to allow access to the mounting bolts. Water can get inside and create a rust spot on the inside of the drum by that access hole. If you don't install the drum the same way, that spot of rust will hold the drum away from the mounting surface making it appear out-of-round. Professional technicians will clean that rust off before machining them. If they were machined with that rust still there, the drums are definitely egg-shaped now.
Did you have the drums machined? Also, if they were rusted tight and you banged them off with a hammer and pry bar, they are likely warped and must be machined.
One thing that a lot of people do to cause problems is not use a torque wrench on the lug nuts. This wasn't important many years ago with heavy rear wheel drive cars, but with lightweight vehicles, proper lug nut torque is critical. Most Chrysler cars and minivans call for 95 foot pounds.
There are four reasons to torque lug nuts. First, over-tightening causes stripped threads that may not show up until the next time someone removes the wheel. Of course, the technician removing the wheel will get the blame. Often the lug nuts have to be cut or chiseled off and the wheel can be damaged.
Tightening the nuts to specs insures a 90 pound person can get them loose to change a flat tire.
Under-tightening lug nuts can lead to the wheel coming loose and wobbling out the friction surface the nuts contact.
Most importantly, lug nuts that are not torqued to the same value lead to warpage of the brake drum or rotor from the uneven stresses during the heat and cool cycles.
If I ever saw a technician installing lug nuts with just an impact wrench and not following up with a torque wrench, I would mention it to his boss, and probably never go back to that shop.
One final note about lug nut studs. Do not use anti-seize compound on the threads. The nuts WILL come loose. Some people insist on using grease. If you do, use very little, then thread the nuts on all the way by hand and torque them. Don't use air tools because the grease will build up on the friction surface from the centrifugal force and allow them to work loose.
Monday, March 23rd, 2009 AT 7:00 PM