Just a very general hint: IIRC the Durst RCP units were at the time (late 70s?) engineered and manufactured by German company Thermaphot. Later Thermaphot started producing their own brand table top RT processor (the ACP series). As the owner of Thermaphot is still around and offers parts and service for his machines, those of you who are looking for specific parts like cogwheels, pumps, rollers etc. might contact him. I have no idea if he is able or willing to support the RCPs, but in desperate cases one could at least give it a try. The contact details / email address can be found on the Thermaphot website.