You can try H&R they are located in eastern New York.The exact town I'm not real sure of.You can also try your local Cat dealer or any aftermarket track store.
You can try MacFaddens in Sharon Springs ,If they don't have the parts they will probably send you to someone who does.
www.macfaddens.com look at the sept 26 09 auction . a 52 cat D2 dozer with only 1500 original hrs