Stuff: Motor brushes

Washing machines, at least mine, use a universal electric motor to provide high torque at low speeds; the disadvantage of this is that brushes are required, and brushes wear.

So if your washing machine - or power tool, or food mixer, or something - has stopped working, it might simply need a new set of brushes!

Motor, botttom right, drives the drum via a belt.

My particular washing machine, a Bosch frontend loader, announced "F43" error code, which a quick look at the internet told me "faulty motor" and in particular motor brushes. So long before you get someone in or buy a new machine, have a quick look!

The back came off easily, a belt connects the motor to the drum which slips straight off. In my application it was going to be easier to take the motor out, this required removal of two bolts and disconnection of the electrical plug. Note that electrical plugs will have catches on them, you will have to squeeze some part to pop it off. This is so that vibration under operation doesn't cause the plug to fall off.

Looking at the back of the motor in this photo you can see two white holders the brushes go into. They are on a slight angle, so the brushes are cut at the same slight angle - take a careful look and think about which way they come out so that you can put the new ones in the same way.

Back of electric motor, brushes go into white slots at an angle.

The brushes are held in with springs, they will clip in somehow, you will work it out. Upon inspection it was pretty clear that one had worn down below the minimum limit. So now you know, where do you get new brushes from when wifey wants to put a load of washing on in the afternoon?

I checked with my local electronics shop, toolshop and auto shop. The auto shop had something that was the same but it was not carbon it was more of a brassy thing. So basically nothing. The tool shop said that they do have a lot of carbon brushes but unless I quote them the exact part number they won't match them, they've been burned too many times.

Worn brushes versus new brushes.

But online, there they were. The exact brush I needed, about twenty bucks...but in a different state, about a week away in delivery time. Can't go for a week without the washing machine, not with three kids!

This is what I did. Do this at your own risk. I'm not saying to do it, but it worked for me.

While you are waiting for your brushes to be delivered, put back in the one brush that still has a bit of meat on it (they will wear at different rates, I'd be surprised if one wasn't clearly shorter than the other). The other brush, put it back in backwards. Since the brush is on an angle, that means there is a bit more brush on the other side. I filed the tip of it so it had a slightly flat surface rather than to a point, I don't think you really need to.

What this will give you is a bit more operational time, the brush will make contact again but across a much smaller surface area. This "should be okay". After a week of operation my new brushes came in, I installed them, no worries, whe'll be right for another decade :-)