Winfield Fixture Bleeding Procedure


  1. Remove Clamping Head from fixture by removing its four Attaching Screws.
  2. Position Clamping Head in a vise or similar clamping device with Master Cylinder Screw facing up. Remove Master Cylinder Screw & Retaining Plate by removing the four Retaining Plate Screws.
  3. Using a large snap ring pliers or similar tool, remove the Master Cylinder Piston by grabbing hold of its counterbore & pulling straight up. Damage to the counterbore in the piston can be minimized by lining the counterbore with shim material or abrasive cloth. Be careful not to damage the Master Cylinder Bore. The piston may begin to draw vacuum while being pulled out & offer some resistance. If this occurs, open the Bleed Screw located at the end of the Valve Body closest to the Master Cylinder & continue removing the piston. Close Bleed Screw once piston has been removed.
  4. Open all valves & push all the Anchor Pins in and then close all valves.
  5. Fill Master Cylinder to brim with S.A.E. 10 Weight Hydraulic Oil.
  6. Open valve #5 & using a snap-ring pliers. Slowly pull anchor pin #5 fully out (pin will come to a stop and cannot fall out) and then push fully back in. Repeat two more cycles and then close valve #5.
  7. Repeat step #6. for remaining valves & anchor pins in sequence #4 to #1, being certain to close each valve before moving to the next.
  8. Repeat one more cycle for all valves & anchor pins, #5 to #1.
  9. Open all valves and refill Master Cylinder to brim with Hydraulic Oil.
  10. With its o-rings installed, lubricate piston with Hydraulic Oil and install into bore until flush with Clamping Head Surface. Some pins will partially extend while piston is being installed.
  11. Rotate Master Cylinder Screw fully back in its mounting plate (counter-clockwise as viewed from the knob side) & install into the Clamping Head.
  12. Position the Clamping Head on a benchtop or in a clamping device with valves facing up and in such a manner that all (5) Anchor Pins can be compressed simultaneously. You may want to use a block of wood or aluminum to bridge across all of the Anchor Pin Faces.
  13. Crack both Bleed Screws located on the Valve Body (one at each end) approximately (2) turns each and push the Anchor Pins in simultaneously until flush with the face of the Datum Plate. Close Bleed Screws. Be certain that the Clamping Head is supported from below during this step as very little pressure is exerted against the Clamping Head once the Anchor Pins are flush with the Datum Plate.