Is there something he didn't do right?

He should not have rotated your tires without first asking you especially if are using different sized tires. Secondly, replacing a wheel bearing does not require a wheel alignment. Personally I would question his integrity and honesty in this case. If the car is shaking I would definitely take it back and demand he put the tires back as they were before rotating them. Rotating tires is a good thing to do to get even wear but only if you are using the same sized tires.

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If the tires on the front were in better shape than the rear, then you did need the rotation. The best tires should always be on the front of any vehicle.

Two things could be causing the front wheels to shake. One is an out of balance tire. The rear tires may have been out of balance prior to being moved but you did not notice or feel it until it now. Rear tires that shake are felt in the floor and back seats. When moved to the front, it becomes obvious because it is transferred to the steering wheel.

Another source to check would be an incorrect bearing installation. If the bearings are not installed right, the car will shake and the bearing will not last very long. Lift the front wheels of the ground. Now grab the tire at 9 and 3 o clock and attempt to force the wheel to wobble back and forth. A loose bearing will allow the tire to move slightly. There should be no play at all in the wheel.

I would have the tires balanced first, if this doesn't solve the issue than look into the wheel bearing. Also wheel bearings should not be replaced one at a time. Always do both sides. When one bearing is new and the other one is not, the older one will put up more resistance while the new one spins properly. This will cause the car to pull to one side and shake.

Automotive tires should certainly be rotated to prolong the longevity of the tires. This should be done approximately every 6 to 8k miles. However you have different sized tires on each axle? If your vehicle was not design to run staggered sized tire this could be a major problem for you. Lastly, Jay is dead wrong on where to mount new rubber. The best tread should always be on the rear axle of your vehicle to lessen your risk of lose of control and hydroplaning.

http://blog.tirerack.com/blog/hot-seller/two-new-t...

You need to find a better mechanic, who does not do work that you do not request (tire rotation), and try to upsell to work that you do not need (alignment).

You might need to get your tires balanced, though, to get rid of that wobble. If he's truly the dodgy type, he may have knocked off one of the wheel weights.

To avoid this in the future, you should really take a beginning automotive repair class at your local community college. You will save a ton of money during your lifetime. (Replacing a wheel bearing on most cars is really easy, by the way.)

Definitely if you are facing any unusual problems...you must consult him again..that will be better...

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