Nexen BC288A 835200 - Manual (Page 7)

7
FORM NO. L-20066-C-1209
MAINTENANCE AND REPAIR
NOTE: Periodically inspect all airline connections
for leaks. Inspect all fasteners to make sure they are
tightened to the torques recommended in Table 1.
NOTE: Depending upon the Brake Caliper accessibility,
friction facing replacement and piston seal main-
tenance can be performed without removing the brake
from it’s mounting.
2. Replace the Friction Facings (Item 5) when they are
approximately 3/16 inch thick:
a. Spring Actuated Unit: Apply 90 PSI hold-off pres-
sure at the air inlet or manually release the brake
as described in paragraph B.1 of the OPERATION
section.
b. All models: Remove the Shoulder Screws (Item 11).
Remove the facing/shoe assembly (Items 4 & 5) and
Spacer (Item 6). Remove the Machine Screws (Item
9) and replace the Friction Facings.
c. All models: Reassemble the Spacer, Shoe/Facing
assembly, Springs and Shoulder screws. Tighten the
Shoulder Screws to the torque recommended in Table
1.
d. Spring Actuated Unit: Reset as described in paragraph
B.2 of the OPERATION section.
3. Air Actuated U-cup and O-ring replacement (Items 10
& 14):
a. Disconnect the air supply to both cylinders.
b. Remove the clamps (Item 8) and end caps (Item
2).
c. Pull the Pistons (Item 3) out of the Cylinders (Item
1) and remove the U-cups (Item 10). In spect the
Sleeve Bushings (Item 15) for wear and replace
if necessary.
d. Lubricate the new u-cups with O-ring lube and
place them, with the seal lip upward, over the small
diameters of the pistons and into the grooves.
Slide the pistons into the cylinders.
e. Lubricate the new O-rings (Item 14) with 0-ring
lube, place them into the end cap grooves and
re install the end caps and clamps. Tighten the
clamp bolts to the torque recommended in Table
1.
4. Spring Actuated u-cup and O-ring replacement (Items
10 & 21):
a. Disconnect the air supply from the air inlet.
b. Manually release the Brake Caliper as described
in Section IV, paragraph 2.
c. Loosen the clamp bolt and carefully remove the
Clamp (Item 8) The actuating springs will push the
End Cap (Item 2) away from the cylinder. Remove
the Springs (Item 19).
d. Slide the Piston, Spacer, Set Screw and Hex Nut
as sembly (Items 3, 18, 20, 17) out of the Cylinder
and remove the U-cups and O-rings.
e. Lubricate the new U-cups with O-ring lube and
place them, with the seal lip upward, over the small
diameter of the pistons and into the grooves.
f. Lubricate the new O-rings (Item 21) with O-ring
lube and install in the O-ring grooves.
g. Slide the Piston, Spacer, Set Screw and Hex Nut
assembly back into the Cylinder. Install the springs
and place the end caps on top of the springs. Push
down on the end caps until they are flush with the
Cylinder Flange; install the clamp and tighten the
clamp bolt to the torque recommended in Table
1.
NOTE: A ‘C’ clamp, used to compress the End Cap
against the Cylinder Flange, will facilitate assembly.
h. Reset as described in the OPERATION section.
CAUTION
Working with spring loaded or tension
loaded fasteners and devices can cause
injury. Wear safety glasses and take the
appropriate safety precautions.