I have an 86 bronco full size and the back window wont roll up,help changing motor?

the motor works but it just wont push it up,, anone wanna tell me how to replace the motor an easy way|||open the tailgate, take out all the screws , or pop loose the uphostery cover. you will have to have help manualy pushing or pulling up the window while someone is holding the switch. now you can get down into the tailgate to replace the motor.