Mamod SE2a whistle repair

The whistle on my SE2a was passing steam. I originally tried to fix this with a small O ring, but today I decided to have another look. This is an early version of the lever type whistle, using a taper on the bottom of the inner shaft to make the seal rather than the O ring found on later whistles;

I stripped it down by holding the upper section of the body in a vice, mine has soft jaws, and turning the lower part with a spanner on the hex. This was after a 48 hour soaking in Plus Gas. Both body parts are held together with a light interference fit.

This is the lower tapered section, which makes the seal;

I put a few drops of Brasso on the taper and turned the inner shaft inside the lower body a few times until there was a witness mark all the way around the shaft;

Re-assembly is just a matter of pressing the two parts together, not forgetting the separate plunger which acts on the top of the inner shaft (I did!).

Of course I had to test the whistle by steaming the engine, and there is an improvement although there is still a slight leak. But I can live with that.

Here it is driving a Wilesco piller drill;

A nice simple job for a tired Friday afternoon.

Paul.