I agree...pay for it yourself, learn and get a cert if so awarded to become a certified repair tech.
Then, when they ask you to fix a reg, quote them a rate you feel appropriate for your time. If they don't want to pay for your services, so be it.
Then, when they ask you to fix a reg, quote them a rate you feel appropriate for your time. If they don't want to pay for your services, so be it.
I would suggest you pay for it yourself. That way the shop doesn't think they have an indentured servant and pay you peanuts. If they do then you are free to take your talents elsewhere.
Knowledge is power.