While you wait for answers, we may have found some information which could help you.
Click here for Changing Belt ChangeEureka Model 4870 Motor Replacement?
Eureka 4870 vacuum?
Eureka "boss" #5893 stops sucking after 10mins?
how can i fix eureka boss capture?
how can I fix my Eureka 431?
eureka 4870B smartboss, upright vaccum?