Hi,
Neil Jarrett here and can confirm I would send parts to Chile but have checked and generally it can be expensive. In the case of a set of replacment track rubbers it would nearly double the price. Please note this is only my hobby but should generally be able to assist.
Is it possible your MG5 was used for mining rather than agriculture as many accross the world were being small but very strong.
If you email me at njarrett@btinternet.com I will send you a copy of my available new spares list.
Neil