F type - Tech Tip 1
photo One of the many problems on an MMM car is the braking system. This is what I do now to get it working as it should. It is obvious that every part in the braking system has to be in good condition but there is always the problem of worn brake drums. When the inside of the brake drum has got bigger through wear or machining, the brake shoes and linings will not match up perfectly.
Over the last few years I have tried different methods to skim the non-asbestos brake linings to a perfect fit with the drums.
You have to use a slightly thicker brake lining than original to compensate for the worn drums. So I made a dummy backplate with shoes and linings to put in the lathe and turned everything down to a perfect fit with the brake drum. One has to be very careful and take precautions that nothing comes loose when turning this contaption in the lathe. This worked quite well but I noticed some differences in the backplates. photo
I tried the usual method of putting a back-plate with shoes and linings in a big lathe and turned everything down that way. The results were a lot better but the work involved tripled.
So now I use a skimming device based on talks with other fellow MMM enthusiasts. As the picture explains you need a small slide from an old lathe or milling machine with a good cutting tool.
photo The top bolt is used to move the cutter downwards and cut the exact diameter you want. When holding the bottom pulley and turning the device on the hub the slide will move forward and the cutter will slowly progress. If you want the cutter to come back then turn the belt. There is no point in giving exact dimensions as they need to be adapted to the slide.
It is a good idea to put two pieces of cardboard (0.5 mm thick) under the brake shoes before you start cutting.

The brake lever will then have a minimal movement before it pushes the whole brake lining against the drum.The big steel cylinder at the bottom is just a balancing weight. It now takes about half an hour to do the brakes on one car. You will see that now the drums will move easily over the shoe and that there is no more cursing involved.

Happy Braking,

Stefaan Vernyns
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