First step, is always explain to a customer that anything 3" of edge is a critical repair. Which means the slightest additional pressure of any kind could posssibly cause it to run. When I find customers that don't believe me telling them this, I will joke with them and ask for their thumb so I can prove it. So far, nobody has ever taken me up on that offer.
Next thing I say, is from all my past experiences if this damage is left unrepaired it will spread on it's own 99% of the time within days or a few weeks. Now the customers expectations aren't so high and will just tell you to go ahead, do your best and try to save it. Takes alot of pressure off you and the customer in case something does go wrong. Being that your in Mexico I'd definately make sure the shield is cool before you even set up. Not a bad idea to call them up 1-2 hours before your scheduled appointment and ask them to park in shade or in garage. If it's 1" from bottom, chances are it's right on the frit or urethaned bonded area of the shield which makes it even more critical. These repairs should never be rushed or left unattended for even a second. Think of this repair like having your 3 month old in the bathtub unattended
Why ever chance it?Start out this repair by using the least amount of valve stem and piston pressure and just work your way up in very small increments. If you do need to use a probe with filling stubborn legs.... make sure it's also done in very light and increasing stages.
Good Luck....let us know how things turn out!
