http://stravaiger.com/blog/tags/bleeding/ Recent content in Bleeding on eBothy Blog Hugo en-us Wed, 10 Sep 2008 00:00:00 +0000 http://stravaiger.com/blog/2008/09/10/the-power-of-instruction-bleeding-your-brakes/ Wed, 10 Sep 2008 00:00:00 +0000 http://stravaiger.com/blog/2008/09/10/the-power-of-instruction-bleeding-your-brakes/ <p>I&rsquo;ve got a task to perform which I&rsquo;ve never done before. Bleed my mountain bike disc brake. On a trip to the &lsquo;gorms I was cycling out from Red Bothy and the front wheel locked solid. I had to stop every couple of minutes to let the caliper cool down and prise the pads from the rotor. I&rsquo;ve since found out it&rsquo;s because I haven&rsquo;t changed the fluid in ages and you should ideally bleed them every 6 months. The slightest rubbing of the pads on the rotor causes the calipers to heat up, which in turn transfers heat to the brake fluid, which being rather old and hydrophilic by nature, had been contaminated by minute amounts of water. The water then heats up and expands, causing the pressure in the cable to increase, pushing the pistons out and the pads to contact the rotor, which increases the heating effect and creates a vicious cycle, quite literally. The net effect is a wheel that is increasingly difficult to turn and so I had to stop every couple of minutes all the way back to the Linn of Dee. I suspect the crossing of the Geldie Burn on the way to and from Carn an Fhidhleir and An Sgarsoch had made the problem worse as the water was knee deep and the caliper had been submerged. The cycle back to Red Bothy was fine but in the morning, the brakes had become locked up as soon as I left for Linn of Dee.</p>