Worn Hotpoint Carbon brushes

Here is a picture of a pair of worn Hotpoint carbon brushes. Both carbon brushes are approximately 80% worn but the carbon brush on the left is still making good contact with the armature.

The difference between the two carbon brushes is that the faulty one on the right is charred and sooty at the tip. It's taken on a charcoal-like appearance and there is evidence of burning present. The good carbon brush on the left is smooth and shiny at the tip which shows no sparking has been occurring.

If both carbon brushes are smooth like the one on the left, then they are still making good contact and are not likely to be causing any symptoms. However, if they are as worn down as this they clearly need replacing, although maybe the fault you currently have is caused by something else.

Hotpoint carbon brushes Ok

This Hotpoint (or Creda) carbon brush is approximately 20% worn. It is the later (laminated type)

The tip of the brush (that runs against the armature) is shiny and smooth, with no evidence of burning and is therefore perfectly alright.

It is possible for a carbon brush that is not worn down significantly to stick inside the holder (which is spring loaded) If this happens, then as the brush surface wears through normal usage, the brush doesn't get moved up and stops making contact with the armature.

If this happens, then the tip of the carbon brush will look charred like the 80% worn one above.

Complications on Hotpoint carbon brushes

This Hotpoint carbon brush is approximately 50% worn but something has gone seriously wrong. If yours looks like this then there could be problems with the other parts inside the motor.

The tip of the carbon brush is charred but note the arcing damage to the brass holder which has been caused by excessive sparking and flashing inside the motor.

If the tip of the carbon brush is damaged to the extent that there is a chunk broken off, (not shown here) then there is a good chance that a raised commutator bar on the armature has caused the fault. This would require a new armature.

If the washing machine has also fused, then this is evidence of electrical shorting inside the motor which you need an insulation test meter and electrical knowledge to diagnose and repair.

Also, if there is damage like this on the brass holder (and especially if the washing machine fused) then the TOC could have blown also. This is then not a simple case of replacing the worn carbon brushes and no longer a straight forward DIY repair job.

Want to buy some Hotpoint carbon brushes? Hotpoint Carbon Brushes page

How to fit new Hotpoint carbon brushes

Do not attempt to repair a washing machine unless you are competent, and have read the washing machine repair safety advice. All motors and indeed the whole of the washing machine should be tested for insulation leaks to earth using a megger (at 500v DC)

Access to the brush next to the tub weight

The top tub weight can be removed to get good access to the carbon brush less than an inch away from it. It's possible to remove and fit a new brush with the tub weight in place but it's awkward. If I'm not removing the weight I use a flat bladed screwdriver bit to lever the old brush out. Some people prefer to remove the motor.

If removing the top weight you have to watch out for over tightening when replacing it, but if you don't tighten it enough it could work loose over time and cause damage. Don't use a tool that can generate too much leverage.

If removing the motor you need to ensure the belt tension is correct when refitting. Note the position of the motor by marking it against the tub fixing bracket. however, if the belt is already too slack through wear you would be better tightening a little when replacing. It should have a nice "ping" when plucked but not be so tight there is little movement. It should be tight enough to not slip under load but still have about a quarter of an inch play either side.

This is a new pair of Hotpoint carbon brushes. They are the later laminated type but fitting instructions are identical for the older (black) type.

Look at the picture (left) of a pair of new Hotpoint carbon (or Creda) brushes. Look at the main plastic body and compare the small brass lugs in the brass strips, which are in the centre towards the back. The top brush has had the small brass tag released (and the carbon brush has popped out) and the bottom brush is still held captive because the small brass tag is still pressed in.

You should receive the carbon brushes with both brushes held safely inside the holders like the bottom one. If one or both have come out of their holder then push them back inside.

The best way to fit them is to slide them into the motor with the brush retracted and captive inside the holder. Then, when the brushes are pushed all the way in the motor so that they click in place, you should bend the small brass lug away to release the captive brushes. Make sure you bend the lug as far as it will go (out to a 90 degrees angle) or the brush may stick inside the holder and cause problems. I personally use a Stanley knife blade to do this.

It is easier to release the carbon brushes before inserting them into the motor but this is not the proper way to fit them. The reason for this is that releasing them first carries a risk of the carbon brush snapping, or riding over or under the armature when you push it into the motor. You may not be aware this has happened until problems occur later. If this did happen, after some months the brush could break or be worn in half and the spring released into the motor causing extensive and expensive damage.

Cleaning the commutator

Professional washing machine repairers usually clean the commutator with a comm stick. The commutator is the ring of copper segments that the brushes run against. When new, the commutator is clearly copper-coloured but the carbon brushes deposit black carbon on them. In theory new brushes should run OK on an uncleaned commutator, after all, the carbon brush is made up of highly conductive material and the old ones ran Ok until they stopped making contact through wear.

In practice though, few engineers would be happy to fit new carbon brushes without cleaning up the commutator and it can make the difference between having the new brushes bed in successfully or not.

A comm stick can be purchased but it's an extra expense costing around £10. When I had no comm stick available I used to use a very fine emery cloth. NOTE: using sandpaper, or anything other than a very fine emery cloth can scratch and damage the commutator or embed grit or sand into the soft copper. This can cause sparking and big problems.

Is it safe to repair my own washing machine?

Although fitting Hotpoint carbon brushes is a very simple job physically, if you are a total novice I would not recommend trying to repair a motor on a washing machine. Even skilled and experienced repairmen can get electrocuted if they aren't careful. Please read the advice here is it safe to repair my own washing machine?

I fitted carbon brushes but there are problems

• I fitted carbon brushes but the motor still doesn't work
• I fitted new carbon brushes but the motor is sparking a lot

More on carbon brushes and buying different carbon brushes on next column ... Go to top of page