Any dirt or grease can be cleaned off with Naphtha, available at a hardware or paint store. Scrape off any dirt on the wheels with an X-Acto knife or the blade of a screwdriver, then finish cleaning the wheels with Q-Tips dipped in the Naphtha. A drop of oil on the axles where they enter the wheels will allow better rolling.

The coupler opening is caused by a weak spring 480-38
http://www.ttender.com/weblistpictures/480-38.jpg

You'll need the rivet to hold the spring in place, #2343-66
http://www.ttender.com/list/num8.htm

Replacing these parts will keep the coupler from opening in use.


Larry