Shop Vac keeps burning out motor bearings

Has anyone else had a problem with their shop vac burning out the motor bearings?
This is my second one to do it. I built a ‘quite box’ as I use my cnc router in the house. I thought the problem was not enough air circulation at the motor so on the second one I installed two external fans to blow cooling air over the motor housing. I know this worked as I can feel the air rushing out of the quite box where the suction hose exits the box. Both shop vac’s failed about one year into their use.


Dust collector is the way to go, but if you use a shop vac don’t choke off the air flow this will kill you vac. It needs the air flow to cool itself.

Buy a dust collector or add a Dust Deputy, it will extend the life of the motor significantly. Also, don’t replace the whole vacuum, you can order a new motor for around $30.

if it’s a good quality shop vac it will have separate motor cooling fan and vacuum fans, so the vac air is not doing the cooling, the cheaper ones and household vacs use the vac air for cooling. dust collection system is made for long run times, the typical shop vac uses a universal motor, they are powerful (and loud!) and compact but run hot and are not designed to run for hours at a time.

Just a suggestion (that is, if you don’t buy a proper dust collector), get a dust deputy or some other pre-filter and also use a material “sock” over the internal paper filter. Then, when doing long jobs, turn the vac off for a few seconds and give it a few knocks.

My entirely unsupported hypothesis is that the really fine dust clogs up the filter significantly reducing the cooling airflow through the motor. Turning it off occasionally and giving it a few thumps, allows this dust to fall away from the filter and allow a little more airflow. Because the dust I’m talking about is so fine, it’s often not really noticed when you open the can, and by the time you’ve opened it, much of the dust has already fallen away anyway.

The solution as mentioned above, is to get something designed for doing this task, however if that’s not an option, my suggestion may mean you burn out the bearings every 18 months instead of every 12 months.

Just a suggestions…

This is what I used.

This dust deputy is connected to my shop vac.
I have the shop vac turn on when the spindle turns on.
I do not run the machine as much as others here but it works like a champ and the shop vac does not get hot.

if you can get a exhaust fan you can hook that up to a system and make a great dust collector.

There is a youtube video of a guy who made one out of a motor and wood.

This is pricy but you can see the exhaust fan in it and how it hooks up

I have a cheap harbor freight 1hp dust extractor hooked to a dust deputy, then exhausting straight out of the building. So far it’s worked awesome! Shopvacs, as noted, are simply not made with a 100% duty cycle, with the exception of a couple very nice (and very expensive) options from Festool and Fein.

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Okay guy’s problem solved and I thank you all for your comments and suggestions. I must have not made myself clear on my original text. For all that suggested I get a Dust deputy dust separator I have two of them. One for my garage workshop and another one attached to my shop vac on my CNC router. I also contacted shop vac customer service explaining my problem and they are/have sent me a replacement power head for my model shop vac. A pleasant surprise to say the least. My shop vac is enclosed in a silencer box as I use it in my house spare room and I needed to cut down on the generated noise. I also have added to the silencer box two fans blowing outside cooling air over the head of the shop vac to help with the cooling of the shop vac. According to shop vac it should not have died so soon. So I will re-do the same set up as before and see how long this shop vac works. Thanks again for your inputs.

In addition, my shop vac has no or nearly no dust in the canister. 90% or more of the dust is captured by the dust deputy and go into it’s container!

They really rock, don’t they? Interesting tidbit I picked up a while back when we had some flooding in the house: They work just as well or even a bit better on liquids!

Do you guys have shop vacs that use the “suck” air for cooling? the one i have doesn’t and I was under the impression that’s what made a shop vac a shop vac? Also when you block off the suction and the motor speeds up it’s because it’s working with less load (and lower current) because the fan isn’t moving much air anymore. I did a current check and my vac uses 10A with no restriction and 6.8A fully blocked off. sorry for the rambling don’t mean to hijack the thread :slight_smile:

I’m running a $29 shop vac, and dust deputy.

I have the 10 Gallon, 4 amp shop vac and it pulls (sucks) air with authority. If yours isn’t you need to return it to where you purchased it for an exchange, if it is a recent purchase. If not, contact shop vac directly and let them know what’s happening. I did and they sent me a replacement power head when my bearings failed after about a year’s use.

Seems like bearing failure is a common problem. I haven’t had a vac fail that way before, but I’ve had one which blew a thermal fuse and one which had a bad power switch. If a shop vac just won’t turn on, then it’s going to be one of those two issues. Those, at least, can be fixed by yourself.

Sorry in advance for the necro post but i’ve also had issues with bearing failure and i discovered the problem. Almost all of these “cheap” consumer grade shop vacs (shop-vac, ridgid, stanley, etc etc) are largely made by the same company named Emerson. As a cost cutting measure for a world that has become stuck on cheaply made, disposable products… Emerson has designed a motor with only one sealed ball bearing, and on the other end of the motor shaft is a bronze “Oilite” ( ) type bushing surrounded by felt that holds the lubricating oil. While i have nothing against such a bearing in general (they work just fine in my 100 year old GE table fan), the use of them in this motor design where they are not serviceable is clearly a way to make these vacuums have built in obsolescence. Or to put it bluntly, they self destruct once the oil is used up, overheating the bearing and motor causing a thermal fuse to break, disabling the vacuum. Typically such oil bearings are accessible in properly designed devices and can last many decades with very little maintenance but not in this case.

A while back I did take apart my 14 gallon Rigid shop vac when I heard a change in the sound of the motor and i’m kicking myself for not taking photos, but as I thought, the felt that once held a supply of il was dry. I gave it a good dose of 3-in-1 Oil for electric motors (comes in a blue can), put everything back together, and it ran like new again. Keep in mind, i did this well in advance of a bearing failure and was able to prevent the issue. The longer you run the motor, where it begins to squeel loudly, a re-oiling may not be enough because the friction smears the surface of the oilite bearing causing oil to no longer flow through its highly porous structure.

After a bit of searching, it seems a guy on youtube who was also having the same problem came up with a MUCH better solution than re-oiling, and that is to replace the bushing with a 608-2RS ball bearing which just happens to fit perfectly into the housing.

Check it out!

I will be doing this to my Ridgid 1450 vac in the very near future.

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