I have an older Wagner Power Roller Model # 0156030. Just recently, I lost a plastic nut which holds the pump assembly in place (part #0156417). I have been uable to find the Wagner web page and try to order the part. This machine is very dependable and saves a lot of time. I don't wish to buy another system when all I need is a small plastic part. Can you either provide me the Web address or phone number in which I can order this part?