BRAKE TECH

Igot a bunch of promo stuff from Repco the other day, talking about their Radial Chamfer Technology for brake pads. Hot new stuff, eh? Well, not exactly. The idea is the leading and trailing edges of your disc pads are chamfered a little, which can help to reduce brake squeal. Well, they must have been talking to a 60-year-old mechanic, because people like me in the trade were doing this decades ago. Which isn’t to say it’s a bad idea, as it does work.

Back in the day when discs first becamse widely-used, the pad technology was way behind where it needed to be. The compounds really needed work to fine-tune the compromise between longevity and grip. Believe it or not we had similar problems with drums over the years.

This might sound familiar: a cheap component in this area will often deliver bad results. Given the minimal cost premium, I’m keen to use known reliable brands in a brake set.

If you’re doing disc pads at home, everyone carries on about having a perfect surface on a disc rotor, but truly it’s not that important. The odd groove is nothing to stress over. If they’re shiny and looking a little glazed, hit it with a bit of emery.

While you’re in there, clean out the calipers. And yes, the chamfered pad designs do work. You hear all sorts of alternative theories on elimninating squeal, such as using a tiny amount copper grease behind the pad, but I’m not a fan of that. It doesn’t work, and nor does the alternative theory of using a bit of silicone.

Since we’re on the topic of brakes, let’s talk about doing a simple f luid change to celebrate the coming of warmer weather. It’s not actually a huge job, and brake f luid does absorb water which eventually causes trouble.

So, the simple meathod is pop the top off your master cylinder, and remove as much of the old f luid as you can (a couple of throw-away rags will do), then top it up with fresh stuff.

Place a hose and catch bottle on the bleed point furthest away from the master, open the bleed nipple and have a cup of tea. Gravity and atmospheric pressure will do the rest.

It will take a while, and make sure you don’t allow the f luid in the master reservoir to run out. Stop when you start to see fresh f luid coming through.

Then you repeat for the remaining wheels. Simple! There’s no need to pump pedals, or bleed the system, so long as you keep an eye on it.

Generally, for older vehicles you now use DOT4 f luid. Don’t be tempted to try DOT5 as it’s not compatible with the earlier f luids.

You can switch an old system to the later synthetic f luid, but you will need to change all the seals. Really, DOT4 is fine and I’d be happy to leave it a few years between changes. Five tops.

If you want to keep an eye on the quality of the f luid, you can do that by getting a cheap f luid meter from your nearest Bursons or Repco or similar, and that will tell you how good or bad the water contamination is.

Last tip, place some damp rags under the master cylinder, to catch any unintentional spills. If you do spill some on paint, use heaps of water to wash it off and throw away any clean-up rags.