Service and Repair Manual

AN 01-25CN-2

PARAGRAPH 4

     d. Hold the spring in this position and lift the yoke to clear the spring guide and pull it out of the housing through the window. The spring and guide can now be removed by releasing the pressure on the arbor press.

     e. If an arbor press is not available, a vise that will open far enough can be used to apply pres. sure horizontally.

   (h) TO ASSEMBLE THE MASTER BRAKE CYLINDER.

     1. Before startinz to reassemble the master brake cvlinder, examine each part thoroughly and replace all worn parts.

     2. Reassemble the transfer valve as follows: Hold the transfer valve upside down, drop in the disc and make sure that it lies flat on its seat to avoid damaging the disc when the retainer is screwed into place. Be sure that the gasket is in place at the bottom of the well in the cylinder and that it is in perfect shape, before installing the transfer valve assembly. This gasket has no function to perform during the filling and bleeding of the system, but it must hold tight against the pressure in the system when the unit is in operation. It may be found easier to reinstall the valve assembly if the gland and two packings are removed from the valve. Screw the valve in part of the way so that the start of the thread is approximately flush with the top surface. Install the two packings in the well one at a time and screw the gland on.

     3. Before reassembling the housing, grease the entire inner surface of the housing with a heavy grease of high melting point, preferably a rocker arm lubricant for corrosion protection. When installing the parking spring be extremely careful not to let the spring snap up against the light bridge on the yoke as it may cause serious damage to the yoke.

     4. To reassemble the housing, reverse the pro. cedure outlined above. Do not install the housing end until the housing and cylinder are assembled together.

     5. To reassemble the cylinder, reverse the procedure outlined above. Wet all cups with hydraulic brake fluid to facilitate their entrance into the cylinder. Do not install the upper end fitting until after the housing and cylinder have been assembled together.

     6. Assemble the housing to the cylinder by slipping the housing assembly over the piston rod

protruding from the cylinder assembly. Insert a clean wooden hammer handle into the open upper end of the cylinder and push the piston down until the rod has protruded far enough through the yoke on the bottom of the housing to engage the nut on the threaded end of the rod. Turn up the nut so that the rod threads do not protrude through the nut more than 1/32-inch to 3/64-inch, to insure that the rod will not foul the end fitting. Install the cotter pin in the nut.

     7. Grease the threads on the lower end fit. ting and the thread face of the housing assembly with a heavy grease and screw the end fitting onto the housing assembly. The last few turns will produce considerable drag as the heavy parking spring is being depressed. Line up the lock screw hole on the housing and end fitting and insert the lock screw.

     8. Grease the threads on the upper end fitting to protect the threads against corrosion and to seat against slight seepage during the filling and bleed. ing operation. If it is desired, a non-hardening sealing compound such as key paste may be used. Apply the waling. compound sparingly so that it will not mix with the brake fluid which is in contact with the upper end fitting.

     9. If the nipple on the elbow installed in the 1/4-inch pipe tapped hole in the cylinder has been removed, or a new replacement fitting is being installed, use thread lubricant to seat the connection.

   (i) TO DISASSEMBLE THE HYDRAULIC BRAKE CYLINDER.

     1. GENERAL. - The double-end hydraulic cylinder is mounted near the top of the torque plate by two cap screws. The cylinder is attached to the brake shoe at each end by levers attached to the two cy. linder piston rods. To remove the brake cylinder from the torque plate, proceed as follows. (See Fig. 61.)

     a. Unbutton the 4 Dzus fasteners attaching the outer fairing to the wheel.

     b. Pull the cotter pin and remove the nut on the end of the axle.

     c. Pull the wheel and tire assembly from the axle, exposing the brake shoe and torque plate. Hold a clean cloth over the center of the wheel as it is being removed, to prevent the bearing from failing out and collecting dirt.