Tires: Tire with Plug is leaking air, ford mustang, slow leak

Question
Barry,

I drive a 2001 Ford Mustang (without anti lock breaks) that has a slow leak in one of the tires. The tire with the leak had a plug put in about two months ago.  Aside from the slow leak, my tires seem to be in good shape.  I had all four replaced about 20 thousand-miles ago and these are supposed to be 40 thousand-mile tires.  They have been used under normally conditions and I've rotated them regularly (no racing or anything like that).

Would it possible for me to have the plug repaired?  Would fixing the plug be a smart decision, assuming that the leak is actually coming from the plug?  If I need to replace that tire should I have 4 new tires put in?  As you can imagine I don't want to spend the money on buying 4 new ones if I don't have to.  

By the way, my steering wheel shakes when I break.  This could be a separate problem, but I just thought I'd let you know in case it's somehow connected to the leak.

Thank you for your help...it is truly appreciated.  

Answer
Not only is it possible to have the plug repaired, it is strongly suggested.  Plugs by themselves are not proper tire repairs - they are considered temporary (and your leak probably is the proof to that statement.)

If you replace it, will you need to buy 4 tires?  Maybe.  If the tires are approaching wear out, then yes, it would be a good idea.  Even though the tires may be rated for 40,000 miles, the actual wear on a set of tires can vary greatly, depending on the alignment, and how much time you spend on the freeway (basically driving straight ahead), as opposed to making turns, because cornering is where most of the tire wear occurs.

The vibration during braking is warped rotors, and they ought to be fixed as well.

Hope this helps.