Recently AddedToday we have had in our workshop this Bosch washing machine WAE24367GB/40 showing an error code of F21 this will apply to many if not hundreds more different models of Bosch machine, how to replace carbon brushes on a bosch washing machine.
A fault code of F21 displaying in the digital display of a Bosch washer usually indicates a fault with the motor, most commonly the carbon brushes, they may have worn down so much that they are not completing the electrical circuit through the motor.
These are the steps we took to repair this machine.
Disconnect the machine from the mains supply
Disconnect the water and drain hoses from the supply
1, To make this easier for ourselves we leant the machine against a wall so we had access to the back panel, we removed the screws holding the panel in place and now we can see the drum pulley and the belt going around it and the around the motor pulley, we gently removed the belt being careful as the machines cabinet has very sharp edges.
2, We now remove the 2 bolts holding the bosch washing machine motor on, in our case these were 10mm, it’s a tight area to work in but is easily enough to do with a little patience, we are being careful of the sharp edges on the cabinet.
3, We can now gently remove the motor off the locating lugs on the washing machines outer drum assembly and lower the motor to the floor being careful as the motor is fairly heavy and we don’t want to drop it otherwise we could damage it, now we can remove the earth cable and the motor wires from the motor so we can totally remove it from the machine.
4, Now we can inspect the motor and the worn carbon brushes, on this particular motor type they are spring loaded and held in by little clips that are not instantly noticeable. We just press in the clips and remove the electrical tag, then there is a cut out where the brush sits we just move this forward and the brush springs out.
5, Having removed the old brushes we can see they have totally worn down, comparing them to the new motor brushes that we will be fitting its very obvious, we now simply replace the carbon brushes in the motor the same way as we removed them and put the machine back together ready for testing.
Sometimes after replacing the brushes the machine will need resetting.
After the carbon brushes have been replaced and we then turn the machine back on, sometimes the same fault code will still be there, now we have to reset the programme
1, Turn the dial to the off position 12 O’clock,
2,Turn the dial to spin setting or 6 O’clock and wait for the lights to flash.
3, Press and hold the spin button for 5 seconds.
4, Turn the dial one position clockwise while still holding the spin button.
5, Keep the button pressed in for another 5 seconds.
6, let go of the spin button and then turn the dial back to the off position this should now have reset the machine, if it doesn’t repeat the process.
Once the machine is working again there might be some noise coming from the motor, this is common as the new brushes start to bed in.
Carbon brushes on a washing machine are there to transfer current to the motor through the armature, they sit on what’s called a commutator.
During normal use of the washing machine due to the friction caused they are worn down gradually over time, the more the machine is used the faster this will happen, some machines with a very fast spin speed over 1200rpm tend to wear the motor brushes down faster.
Some indicators that the carbon brushes are ready for replacing.
