Hotpoint washer WF540 – stopping and starting

Had this weird fault this afternoon, owner says the drum was turning and every now and then refused to start. Left it a while then it started up when pressed.

Checked the heater and it is sound, insulation is sound.

Checked the machine and found the brushes were worn, replaced the brushes and cleaned motor. Good as new and refitted to the washer. Spins nicely when I was there. Left the house then a phone call few hours later saying the fault returned.

Been a while I worked on Hpt WF540 machines, used to do quite a number of bearings change on these. Anyway the machine clearly showed that it was repaired several times over. Owner is keen to keep it going.

Any ideas?