Tractor Repair: TB Super Bronco will not crank, petroleum jelly, earth connection

Question
My tractor will not turn over.  I have tested the battery, changed solenoid, and checked the pinion on the starter.  When I turn the key from off to on position, I hear a click, but when the key is turned to the start position, nothing happens.  Oil and air filters have been maintained.  I'm looking for suggestions before I take it to a repair shop.

Answer
Hi John.
This tells me that you have a poor electrical connection somewhere! could be the battery connections them selves. remove  the main bat leads and and wire brush the terminal and the clamps apply some petroleum jelly to the terminals on reassemble --check all the other electrical connections down the line right up to the starter.

There should not be a trace of any green corrosion on any of the fittings carrying the currant !
Also spray the switch with WD40 inside AND OUT IF POSSIBLE!
make sure the EARTH CONNECTION IS ALSO CLEAN AND TIGHT.
Let me know how you get on.
Martin