Ati, with something that old, you would probably be better off to replace it rather than try to repair it. I doubt you will be able to find parts. Good luck.
Looks like Sears has some parts but not the one I need. http://www.searspartsdirect.com/partsdirect/part-model/Jensen-Parts/RV-appliance-Parts/Model-747E/1558/0418020/00023026/00002?blt=06&prst=&shdMod=[/url]
Trying to fit a new model would be too much plumbing work for a $1000 RV.