Thursday, 24 March 2016

Clippies

In spite of the distraction caused by the arrival of a little brother, these have actually been a productive few weeks for 270 KTA.



I'm very pleased that one little task in particular, added to my loo roll list many sheets ago, has finally been wiped off. Let me explain.

Since I rebuilt them five years ago, 270 KTA's brakes have required regular adjustment to keep them at peak performance. Brake adjustment has always been key with SUs; a former Royal Blue Inspector once told me, "the brakes on 'em were either really good or there weren't any". Consequently I've become paranoid about keeping them well-adjusted and couldn't help but worry that one adjuster always needed more turns than the others....

For the uninitiated, drum brakes work by means of 'shoes' which, when the brakes are applied, are brought into contact with the inside of the spinning brake drum to slow it down. Over time, both the lining of the shoes and the drum itself become worn, and therefore the position of the shoes must be periodically adjusted so that the movement of the shoes continues to take effect on the drum.

It turns out that this was 270 KTA's problem. This spring-clip, fixed to the brake adjuster, is designed not only to give definition to the positions of the brake adjuster (which turns to move the shoe up or down relative to the drum, by means of a thread), but also to lock the adjuster in position. Without it, vibration can cause the adjuster to turn and, in this instance, wind the brakes off! As you can see, the end of this one has broken off.

Don't panic - we're talking millimetres over hundreds of miles here - but it's certainly enough to have made me suspicious over time and feed the paranoia about brake adjustment. With a new clip now fitted, the adjuster should maintain its position over time. On the Inspector's binary measure, the brakes should henceforth be "good".


This was a straightforward job, made easier because I was re-tracing my own steps. Everything came apart easily because I'd put it back together with grease and copper-slip last time. For the first ever time, 270 KTA came quietly and a simple job was even easier than I'd anticipated. Perhaps our friend is finally becoming tame - or perhaps the presence of a sibling role-model is having an effect.


I don't believe either for a minute. This weekend 270 KTA will be in action (for one day only: Saturday) at the South Devon Railway Easter Gala. Immediately afterwards, that nasty crack in the offside lower windscreen will finally become a memory - another little job that's only been waiting for six years....