The MGA With An Attitude
HEATER MOTOR TECH - ET-212 - Pg 1 of 7

This session shows the restoration (more like resurrection) of a defunct heater motor. The problem is, how do you make the one on the left look like the one on the right, and also run like new again?

Heater motor before & after restoration
Heater motor before and after.

Serial Picture Tour For Restoration of the MGA Heater Motor:
Just follow the green arrows.


About as broke
as it could be.

Cleaning before opening.

Parts layout, disassembled.

Filing the

Cleaning up the copper dust.

New brushes installed.

Assembly before closure.

Desired end

Update December 2001. Someone asked me how to get the fan off of the shaft, and the answer is:

As I recall, that is a compression collet. The hub of the fan has a tapered threaded split collar extending inside of the nut. The nut is a deep shell with a slightly tapered thread inside. As the nut tightens the collet is compressed against the shaft to secure the fan with an interference fit on the shaft. This makes the tapered thread a very tight interference fit, which is why it's so hard to get loose.

Start with a good soaking in penetrating oil, and let it sit for a few hours. Then you have to hold the fan to prevent rotation while you unscrew the nut. It has a standard right hand thread, so turn the nut anticlockwise to unscrew. Depending on how far the shaft protrudes you may need a deep well socket. Preferably use a six-sided socket, not a 12-point. Do not attempt to do this with an open end wrench, as it will most likely just crush the nut onto the collet and prevent turning. And try not to bend the fan fins or distort the hub in the process, as any of this would throw the fan off balance.

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© 2000 Barney Gaylord -- Copyright and reprint information