My team doesnt have enough money to buy new motors so we were thinking about fixing the broken motors. We have checked all the motors and sorted them out by the good ones and the broken on. How could we fix them to sound and work like brand new motors?
Get the motor refirb kit and some white grease (robosource has grease). Disassemble, clean, and reassemble each one, with a tiny bit of grease on each axle point and on the gear teeth. Be extra careful about where the wires enter the motor
Frayed motors and broken pins are a bit tougher to fix but very important. Exposed wire can cause nasty shorts.
You will want to make the wire lengths pretty much the Vex wire lengths to be legal. Also ensure the connectors are the same type to nest nicely with the others and are the same type. There are other connector types out there but to stay legal for competition use the same types.
See some parts at pololu for pins, and connector housings. These crimpers are rather frustrating to get right until you get good at it. The most expensive part is the crimper which you could buy a few motors for that cost.
https://vexforum.com/t/replacing-connector-pins-on-393/29946/1
As an experiment, I once repaired the black plastic section in which the motor mount threaded inserts are embedded. That part had snapped off and I superglued the pieces back together, and that fix has held for years.
I tagged the motor with red tape and told the kids to use that motor only for testing purposes, then at the end of last season, I found out they had used that motor on their drive base at Worlds. 