Today I took my C55 to the local Discount Tire to have new tires put on. Driving there the car was fine; no problems, no indication that anything was even getting ready to go wrong. The car goes up on the lift at Discount Tire, new tires go on and they take the car down off the lift and start to back it up. Immediately everyone notices this grinding noise as soon as the car stops to move. Now I have had this happen before. Last time I got new tires, I also got new rims and they put the long size lug bolts in the rear. They were too long and coming in contact with the parking brake. So thinking they might have switched the front and rear lug bolts, or over tightened them, we pull the car forward back on the lift (still making the grinding noise as it rolls), take the wheels off again, make sure the correct lug bolts are with the correct wheels (short ones in the back, long ones in the front), and hand tighten them down with my torque wrench to 81 ft/lbs. I have taken the wheels off and on numerous times using this method (though with the trunk jack) since the first incident with no problems. We spin the wheels while the car is up in the air off the ground. No noise. Put the car back down on the ground, back it up and the grinding noise is there again and when I drive forward. Does anyone have any idea what could possibly be wrong? When standing next to the car the grinding noise doesn't seem to be coming from any of the wheels, more from the center. As I was driving the car 50 feet to the tow truck the noise seemed to be coming from the passenger's side front, but my friend walking along side the car said it still seemed to becoming from the center. The Discount Tire manager was worried that his lift had damaged part of the underbody, but nobody knows. Anyways I had the car towed to the dealership that worked on the problem last time and fixed it, but they can't look at it until Monday. Does anyone have any idea what could have possibly gone wrong. I mean the car goes on lift fine, comes off broken. No change in lug bolts, no change in wheels, just new tires and I have taken the wheels on and off before without any problems. The only difference was that I always did it one by one and Discount Tire put it on a lift and did all four at once. I am nervous because last time it was $900 to fix the parking brake and the tires were already $1000, plus the tow to the dealership was $100. So this has the potential of being a $2000 tire change. I don't want to have to pay for a problem that either Mercedes didn't properly fix last time or that Discount Tire caused. So any thoughts about what could have happened in the 30 minutes that the car was being worked on just having its tires changed would be greatly appreciated. Thanks a lot for the help.

 

where were the jack points

thats also why i put my car up on stands at home and use another car to drive the wheels themselves to the shop

 

I am not sure where the jack points were. I think right behind the front wheels and in front of the rear wheels, but they put "soft blocks" in between the lift and the car, so supposedly the car was never in contact with the lift.