SWING BRAKE VALVES
SUB-SECTION 6F
protective jaws on the vise to prevent damage to the valve
REASSEMBLY. Reassemble the valve as follows:
body.
1. Install new O-rings in the O-ring grooves at each end of
2. Remove the fitting from the brake port, and remove the
the spool bore.
spring and check valve poppet from the valve body. Discard
the fitting O-ring.
2. Lubricate the spool bore and spool with clean hydraulic
oil. Carefully insert the valve spool in the valve body from
3. Remove the screws which secure the end cap to the valve
the end cap end. Position the end cap over the end of the
body. Each screw should be loosened a turn at a time until
spool and install the end cap screws.
the spring force is relieved. Remove the end cap, and slide
the spool out of the valve body.
3. Place the check valve poppet in the valve body as shown
in Figure 6F-1, and then install the spring.
4. Remove the O-rings at each end of the spool bore.
4. Install a new O-ring on the brake port fitting and install
INSPECTION. After the valve is disassembled, perform the
the fitting on the brake port of the valve body.
following inspection:
BRAKE PEDAL STOP ADJUSTMENT
1. Wash all parts in a clean mineral oil solvent and place
them on a clean surface for inspection.
A stop screw is provided to prevent overtravel of the brake
valve spool. This stop screw should be checked periodically
2. Inspect the valve spool and bore for burrs and scoring. If
to be sure it is tight and has not moved. If there is reason to
scoring is not deep enough to cause objectionable leakage,
believe that the adjustment has been disturbed, or if repairs
the surfaces can be stoned or polished with crocus cloth. If
have been made on the swing brake valve, readjust the stop
scoring is excessive, the valve body and spool must be re-
screw as follows (see Figure 6F-2):
placed.
1. Loosen the locknut and back the stop screw out.
3. Inspect the check valve poppet and seat for damage that
would prevent the check valve from sealing properly.
2. Depress the brake pedal fully, by hand, to pull the valve
spool out to the end of its stroke, and hdd it.
3. Turn the stop screw in until it contacts the brake pedal.
Then release the brake pedal and turn the stop screw an
additional 1-1/2 turns and tighten the locknut.
Figure 6F-2. Brake Pedal Stop Adjustment (100J4194-1-A)
6F-2
