Its pretty easy on most machines for vac motors, normally a few nuts and some electrical connections, the hardest thing may be if you need to put new crimp connectors on the ends of the wires if your machine uses them. Just follow whats there.
Quite often pumps dont need replacing they may just need the pump head servicing, You can buy kits for pumptec pumps and there are instruction either with the kit or online. Its all fairly straightforward stuff.
