20-year-old Shop-Vac

Maybe you can pull the rotor and replace bearings--depends on design. Unfortunately, imo by that time there's usually too much wear or the brushes have rubbed to the point of being beyond much hope.

You can either oil the motor, or remove your mother in law.

I'd go with oil the motor.

Only remove the mil if she's not paying her tithe (extortion) faithfully. Why not, your lieing leaders claim she'll never make that 'celestial' kingdom anyway.

-- Learn The Truth About Mormon Doctrine

When my 30 yo vacuum made bad noises I replaced one brush (the other was good) and put heavier oil on the worn bearings; way oil or chain saw oil or slick 50 grease all work well on worn bearings.

According to jhill :

Some of these bearings are relatively standard, so if there's a bearing supplier near you, it'll be worth a visit once you've checked them out and determined they're bad.

Bearing failures are often pretty obvious. Brush problems tend to be high pitched screeches, whereas bearing problems are more full-throated moderate-pitch howls.

Aha! A Shop-Vac? Remember what you had to do to get the motor apart?

Salut!

I called maybe 5 vac repair shops, asked if I could bring motor in, get a cost estimate. They all suggested I should pitch the old unit, buy new.

Not sure where to go from here ...

Cheers, Puddin'

That's true. These dfays its cheaper to just buy another one than repair. What I do with my old ones is to take them apart to see how they are put together. If I can fix it so much the better. If not I have learned something and I have a can full of parts even if they are only screws, nuts and bolts, and a powercord and switch. That something learned can be how to take things apart without gouging or wreaking it. How not to overstress or abuse the gadget when operating it. The wear limits of the various components, etc. Another learned skill is to recognize the extent of a problem as to whether a quick and simple fix can get it back to good condition quickly, a more difficult fix to be done later but in the meantime don't wreak it, to when you know its a tosser without having to disassemble something. I have equipment that are more than 40 years old and still working good.

....

Start experimenting...unless it's riveted, there's a way. There almost as many different motor can designs as vacs so it's hard to say specifically.