Worn out motor brushes

Most pre 2010 washing machines have electric motors that use carbon brushes. Carbon brushes, like tyres on a car, wear proportionally to use. In other words, the more you use your washing machine the more regular you will need to replace your brushes. 8 years seems to be the average life of carbon brushes in front loading washing machines in Adelaide. The picture below is a worn out bosch carbon brush. They come in pairs and are always replaced as pairs.

Worn out Motor Brush

If you enlarge the picture you might be able to see the copper ferrule which holds the wire in the carbon brush. That ferrule can cause damage to the commutator (a bunch of copper segments harnessing all the wires of the armature). If the washing machine has tripped the circuit breaker; it is likely the motor is damaged beyond repair.

We offer a fixed price brush replacement service. Included in this service is the brush set, labour, service call and GST. In 80% of motor related faults, a new set of brushes will successfully restore the machine operation. However, where new brushes fail to restore the motor to service, other contributors can cause a similar condition. Items such as tacho, computer, wiring harness, motor fault can all in their own way cause the motor not to operate.

The catch to correctly diagnosing a motor fault is tangled in an economic reality. Motors and computers generally fall into the uneconomical to repair category.  Wiring harness faults are unpredictable and can take time to find. Tacho problems are normally terminal because they are not normally sold separate from the motor.

So when we are given the go ahead to replace the brushes, it is always based on the understanding that 20% of the time the repair will be unsuccessful, in that it will generally fall outside the “economical to repair” because a new machine these days is around $600.oo. Any repair over half the price of a new one is where most customers choose to buy a new unit.

However, we can continue with the repair until we locate the fault. But it must be made clear, that the next most likely cause will be the electronic controller. No one in Adelaide is capable of diagnosing electronic boards. The method employed to confirm a faulty electronic board is ‘reverse deduction‘. In other words we use a meter to verify the ohm readings of each and every device in the machine, ie solenoid valve, door switch, heater element, pressure switch, pump, etc. So the reverse logic is:- If all other devices are correct, then the electronic board must be faulty. However, that hasn’t included the wiring harness because the time to check each wire end to end is very time consuming.

Experience will normally guide which devices are tested. But the less devices tested means the less complete a diagnosis will be. Some tacho’s can be tested, but will be nil benefit because it can’t be bought as a discreet spare part, it comes complete with the motor. And so on, it might be solved by replacing the electronic control board, but the cost is normally prohibitive. So what we normally recommend is you pay to replace the brushes and cross your fingers! 80% of the time this will resolve the problem. However, in 20% of cases you will have paid the fixed price for replacing the brushes and lost the money involved.

No refund is provided, as the time to remove the brushes and the restock fee is equal to the credit you would receive.