Yamaha RD400 Binding Brakes. The most common Reason Why.

This is my 1976 RD400C - when I first had it in 2005 and got it on the road I came to a stop after a couple of miles. Back brake disc was red hot and locked solid. This seems to effect a lot of owners and causes a lot of debate on various forums and now Facebook. Both master cylinders have a .5mm pressure relief hole that allows pressure / fluid to return to the master cylinders. With age this hole can become bunged up - if it get blocked completely the pads will stay touching the disc which then gets hot and expands and pads will press harder on disc bringing the bike to a halt. I used a sewing needle held by a pair of pliers to brake the blockage. It can be rammed hard in the little hole. My bike does not have the pad shims behind - anyway as per on the video you will see I can move my pads. I had just returned from a ride and discs were warm from brake use. The tiny hole on the front master cylinder is hidden below the plastic reservoir. A lot of people seem to have trouble getting fluid to pump into the system when refilling. Forget the reverse filling and syringe filling - its a load of tosh. There is a simple fix to the problem - better do another video