Posted for Bill Hannahan <wfhannahan@yahoo.com>:

  Several years ago my nylon brake lines displayed brittle failure during the
annual inspection when I flexed them vigorously by hand. The failures occurred
around the knee joint where the tubing was exposed to UV. I replaced them with
1/8 inch nylo-seal NSR (2500 psi) tubing. It slides through the existing 3/16
tubing which serves as a guide tube and shield. From the gear well to the
caliper I added a layer of black polypropylene heat shrink, to stop the UV,
and a white outer layer to keep things cool.

  The critical part is getting the right torque, which is not much on the
small tubing. I suggest getting a few extra nuts and experimenting  to get the
right feel. It is supported down the gear leg and casting to avoid vibration
and stress on the connection.
  There is no delay in application or release of the brakes even in cold
weather and the pedal is noticeably firmer.

  So far, no problems with the 1/8 inch tubing.
  
 BILL HANNAHAN
 WFHANNAHAN@YAHOO.COM