TIRE CORRAL INC

I have a 2004 Toyota Sienna with alloy rims.  The tires have leaked at the rims ever since I purchased the vehicle, including after I had 4 new tires installed.  I have gone to numerous places and no one seemed able to fix the problem.  I have only 42,000 miles on the car and am not about to purchase new rims, which may not solve the problem anyways.
I originally went to Tire Corral 1 year ago and was impressed with their repair of my back 2 tires..  After checking to make sure there were no holes in my tires, they thoroughly scrubbed the inside of the tires and the rims, and re-mounted and balanced them.  This is the first time in literally years that someone was able to fix the problem.  Usually the tires start leaking again within a few weeks.
In addition, the staff was so pleasant, and when I went to pay for the work, they told me, "No charge; Happy Holidays."  (This was the week before Christmas).
One year later, I returned for these same 2 back tires.  This time, I was not impressed.  I made a 500 mile trip right afterwards, and at 40 mph, the steering wheel started to vibrate.  At highway speed, it was almost unbearable, and so I made the trip at less than 65 mph.  When I got to my destination, a AAA rated repair tire shop told me that "your tires are not balanced correctly; there are weights all over the place."  They re-balanced the tires and solved the vibration problem that was created by Tire Corral.  In addition, within 2 weeks time, these same 2 rear tires are leaking again.