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The morning after a fast drive home my SMG hydraulic pump suddenly stopped working. I checked the fluid level and all seemed OK. As I lowered the car and shut the bonnet the pump started working again. A week or so later after another quick drive back from Kent the same thing happened it wouldn't work the following morning. I wanted to check the voltage at the motor end but the morning I was going to do it, the pump was working again! It seemed to me that the most likely cause was the electric motor that drives the hydraulic pump.

I took the motor off the pump - It took quite a while to do this as the earth lead bolt to the gearbox was difficult to remove. A new motor is £230. I thought I might as well open the motor and see what state it was in. Quite a lot of carbon dust fell out and one of the brushes was worn more than the other and had burn marks on it. The commutator was not scored but had burn marks around it.
I cleaned the commutator and ordered new brushes (had to order bigger ones and adjust to fit) and eventually put it back together.

Touch wood it seems to work fine now. For £5 not a bad result. If I have any more issues I will probably invest in a new motor.
Many thanks to Firebobby for the loan of his jack.

Good work OP ! Touch wood my SMG has so far been faultless. Thanks for the heads up.

Likewise, will keep for future reference none the less!

Update. The refurbed motor had been working well - did the national meet and was used daily until 2 weeks ago. We went to Brighton and as I was pulling into the car park I had trouble selecting gears. Luckily I manage to get it into neutral and pushed it into a space. I couldn't hear the hydraulic motor spinning again and so I called for recovery back home.
Out of interest I took the motor off again and opened it up. I found the brushes weren't making good contact with the comm and it looked like the brush spring weren't really man enough. I decided to bite the bullet and buy another motor @ just under £205 which I have just fitted today and all is now fine again.
So, I think refurbing the old motor is still possible but the brushes need to be equivalent of the originals.

The things people do to keep the mileage down on their cars
Glad it's fixed

firebobby wrote: ↑Thu Aug 09, 2018 6:51 pm The things people do to keep the mileage down on their cars
Glad it's fixed

and save petrol too.

Glad you got it sorted Bladeowner and thanks for the info.

Good effort, shame the original fix didn't last

Would this be an age or mileage related issue? Just out of curiosity. My SMG is 15 years old by only on 64k and everything is fine just now, but getting maintenance info on the gearbox before I bought was pretty tough so wasn't sure what to expect.

parabolica wrote: ↑Sat Aug 11, 2018 1:12 pm Would this be an age or mileage related issue? Just out of curiosity. My SMG is 15 years old by only on 64k and everything is fine just now, but getting maintenance info on the gearbox before I bought was pretty tough so wasn't sure what to expect.

Mine had only done 50k but others have done well over 100k without issue and so I think I was just unlucky.