Help can often be found in the Xerox Online Support Assistant here on Xerox.com. The knowledge base articles contain step by step instructions, many with photos, to help resolve all sorts of problems. I have included a link below to the 6180 MFP Knowledge Base, should you need it in the future.
For your specific issue, you will need to contact Xerox Support directly to order the part(s) that you need. This number will always be available at the top of the knowledge base window so you won't have to memorize it. Here is the 800 number for contacting the Xerox Customer Technical Support (800-835-6100).