"Speedbleeders" are one-way check valves that replace the bleed valve(s) on brake calipers.  The one-way check valve does not allow air to get sucked back into the brake caliper, allowing you to loosen the brake caliper bleed valve and not have to tighten and close it during brake bleeding.  This allows for basically one man brake bleeding of the brakes; this makes them very popular with the autocross and racing crowd, as it allows quick brake bleeding at the track.  Keep in mind that "Speedbleeder" is a trademark name.  Russells also sells their version of a brake bleed check valve - easily available from Summit Racing or Jegs.

One cavaet on using the Speedbleeders:  constant use of them for bleeding brakes will wear out the (orange) thread sealant on the threads.  The thread sealant will wear to the point where air will start to get sucked in around the threads, negating the effectiveness of the one-way check valve.  Be aware of this when using them extensively.

FC3S stock front brake bleed valve threads:  8mm x 1.00
FC3S stock rear brake bleed valve threads:  7mm x 1.00

Note:  FC3S stock rear brake calipers have two bleed valves per brake caliper.  You really don't need to replace both bleed valves on the rear.  If you are going to use one Speedbleeder™ per brake caliper, replace the "top" bleed valve rather than the bottom one.

Questions?  Comments?  Send mail to:  reted@fc3spro.com