A Deep Dive into the Sanitaire System Pro (aka Eureka Mighty Mite)
Hey folks, Matt here with House of Vacuums. Today on the bench, I’ve got a Sanitaire System Pro—also known to many of you as the Eureka Mighty Mite. This little canister vacuum has been around forever, and it’s earned a bit of a cult following, for better or worse. Let's crack it open and take a look.
First Impressions
This one came in for a basic check-up—nothing obviously wrong, though it had a bit of a musty smell. That’s pretty standard with older machines. Fired it up and yep—loud as all get out. But that’s just how these things are. They’re loud, brash, and totally unrefined—but they do pack a surprising punch in the suction department for their size.
The switch was working fine, no cracks or signs of damage on the housing where these things are known to break. The only usual suspect showing wear was the caster system. Honestly, these vacs have terrible wheels from the get-go. They're just cheap plastic-on-plastic designs that wobble and grind themselves down over time. It’s a known flaw, but kind of baked into the DNA of the machine.
What’s Under the Hood?
So let’s get into the guts. This specific model is the S3681, assembled in Mexico, and it’s got a 12-amp motor inside—a bit of a rarity for small canisters. What’s even more interesting is why that motor’s in there. Turns out it was originally designed for upright vacuums, like the Victory series or early Whirlwind models. Instead of designing a new canister motor, Eureka/Sanitaire just reused the same one with a few minor modifications. It’s a bit of an overkill in a compact frame, but that’s where the power comes from.
Inside, it’s as simple as it gets—cord, switch, thermal reset, and motor. No fancy electronics or sensors. Just raw, unapologetic vacuuming.
Deep Clean Time
The customer wanted a full clean-up, so I went the extra mile and disassembled the motor for a deep clean. There was a ton of red dust built up around the fan—classic Virginia clay. I carefully cleaned the motor fan, made sure not to damage the plastic housing (which can be brittle), and checked the carbon brushes and commutator. Everything looked solid—plenty of brush length left, and no wear on the commutator.
Bearings were surprisingly smooth too. I added a drop of Teflon oil to lube things up without breaking the seals. If you break those seals, you’re just inviting dirt into the bearing and accelerating failure—best to leave them be if they’re still running smooth.
A Word on Filtration
This unit had a HEPA filter, which sounds nice, but it’s honestly more cosmetic than functional. The vacuum isn’t sealed in any way—air leaks out around the switch, the wheel mounts, and basically every seam. So while the HEPA looks impressive, it’s not doing a whole lot. Still, it was in good shape, so we reinstalled it rather than replacing.
Final Thoughts
These little beasts are like the blunt-force hammers of the vacuum world. They’re not refined, quiet, or elegant—but they’re simple, cheap, and pretty powerful for their size. They’ve got known issues that have never really been addressed, but if you don’t mind the noise and quirks, they can be solid workhorses.
Thanks for coming along for the ride! If you enjoyed this breakdown or found it helpful, go ahead and beep boop that like button. And as always, I’ll catch you in the next one.
—Matt 👋
House of Vacuums
