Fixing a shop vac

Factual Questions
1

I recently spent ten whole dollars on a used shop vac. It worked for a few weeks without trouble. Now, however, it pops a 15A circuit breaker after a few minutes. It starts fine and still produces plenty of suction.

The filter definitely needs replacement, and I vaguely recall that motor brushes wear out as well. Would replacing either of those help? (That’s like… another twenty dollars!) Or is the motor burning out in which case I’d give up on it?

2

I don’t know.

3

Hard to say, do you smell anything burning/getting hot?
Most motors in consumer products are one time and non-serviceable.
Causing a breaker to pop could be a sign the windings are shorting out. If there is no burning smell ((YET)) it could be the motor bearings are worn or just need a little lube. Remember ((non-serviceable)) ? Most electric motors in consumer grade stuff has a permanently sealed type bearing. Once the lube runs out, you throw it away and buy another.
I just checked Wally-World, and they seem to start out around $20.00. I personally wouldn’t have paid anything for a used shop vac, even if it were a High dollar brand. Even the high dollar stuff is made with off the shelf motors mostly.

My opinion is to cut your losses, go get a new one and chuck the old one. If you only use it a few times a year, a cheap $20.00 one should be fine. Weekend shop/diy’er you might do some homework and look for something better.

4

Yes, with Black Friday and all, places like Home Depot and Lowe’s are selling brand new name brand shop vacs for less than $30. They must be loss leaders. Pick one up and if it fails take it back for a replacement.

Yea, it’s a few buck but rid yourself of the headache.

5

Try just removing the filter and see if that helps. Severely blocking the airflow can cause it to trip the breaker*. If not, just chuck it. Unless you can tinker with it yourself there’s no getting them fixed. I just bought Home Depot’s littlest shopvac, a short oval model called Stinger (its black & yellow). Was listed on the shelf as $29 but it rang up on sale for only $19! Walmart has several actual ShopVac™brand ones cheap too…

  • But not for the reason you think: It doesn’t make the motor work harder, the partial vacuum it creates causes less drag therefore *less *strain on it (that’s why the motor’s RPMs increase and the pitch goes up). But it’s damaging because the lack of airflow causes the electric motor to overheat.
6

The motors usually burn out on the brush end rather than a winding because the brushes wear and even break. A brush set should be under $5 at most. I used to keep a crate of old ones around and never purchased any. The expensive pleated paper filter can be replaced with a bag made of paper or cloth. They don’t work as cleanly, but they are cheap and reusable. Maybe that costs $5 too. It costs you only your labor to inspect the brushes. If they are not worn, then the motor bearings may be ready to quit. Check for side play on the shaft particularly at the brush end. The key is always diagnosis first before any spending.

PS> The fuse blowing could easily be due to a short on the plug end or elsewhere. You might not need to take any of the actual vacuum apart. Run the vac and wiggle all the wire from end to end vigorously. If the breaker goes, you know what to do.

7

Thanks, this turned out to be exactly the problem. Tested it earlier this morning, and it ran just fine without the clogged old filter. After buying a replacement filter I was able to vacuum the entire basement.