Fitting Hotpoint Carbon Brushes

It's the sparking that causes this burning. You are right to say they won't physically go in wrong on these motors, but the brushes are held retracted inside their holders (for protection in transit) and so there are some potential problems. When fitting them, you need to prize away the little tab on the brass bar at the side so that they are released. Two possible problems associated with this are -

releasing them before they are inserted into the motor

not releasing them at all, or not releasing them properly

Releasing them before inserting is OK, I sometimes do it myself, but with the brush sticking out it's possible for a brush to ride over the armature when inserted, or even snap, which causes excessive sparking and premature failure. (it doesn't sound like this is your problem though)

The second problem is to do with the little tab holding the brush retracted inside its holder. If this isn't prized fully away, then although it releases the brush, when the brush is inserted into the motor and butts up to the armature, as it naturually pushes back inside the holder it can stick there. Then, when the first millimitre or so of brush is worn away after several washes, the brush (which is spring loaded and pushing against the armature) can't move up and you get sparks jumping across the gap. It can cause the plastic on the brush holder to melt and failure occurs. Take the brushes out and double check that the brushes move freely in and out of its holder.

Another possible explanation for excessive sparking like this is if there's a partial blockage in the sump hose causing the pump to be unable to empty enough water out, but allowing enough out to go into a spin. The washing machine can then start spinning with too much water inside which puts it under strain.

The TOC (thermal overload cutout) will blow if excessive sparking or slowing of the armature causes the motor to overheat. It's replaceable on older Hotpoint motors, but a further unwanted complication and expense. As you guessed, once blown the motor will go dead, but of course a dead motor doesn't necessarily mean the TOC's gone. To test this, you need to test continuity between the blue wire from the brush and the tag on the motor and the yellow wire from the brush to the ajacent tag in the motor.

Related:

Hotpoint & Creda carbon brushes FAQ (diagnostics and fitting advice)

Fitted Hotpoint or Creda carbon brushes and motor still doesn't work

Many thanks for you reply. Can you advise why the brushes I took out had melted, and the new ones I had put in have started to do the same. Is this to do with the armature on its way out?

Could I have put the brushes in wrong? I thought it just a case of popping them back in, they can only go in one way! Also the TOC in the coil field - What is this? Once this has gone I take it the motor will stop altogether.

Thanks