SPYDERLK said:Bob, put a jackstand or something else substantial - wood blocks, from the FLAT ground all the way up to the axle case on the side you are working on. As the tire deflates that side of the tractor will rest on this and the tire will not fully flatten and [perhaps] de bead. The valve core screws out CCW using a core tool. Some metal valve caps have them built in-a little forked spanner at the end. You may want to have a new core on hand to replace it with. There are 2 kinds. You will want the type without the exposed spring.
larry
Thanks for the details! I assume this core tool is something I can get at a local car parts store???
Bob
PS I will brace the tractor as you suggest.