Maintenance; Brake Disc Wear Indicator - Komatsu 930E-2 Shop Manual

MAINTENANCE

Brake disc wear should be checked every 1000 hrs.
using the wear indicator tool (Part Number EF9302),
included in the tool group shipped with the truck. Refer
to Figure 5-2.

BRAKE DISC WEAR INDICATOR

The brake disc wear indicator tool is inserted in a port
which is open to cooling oil. Removal of the inspection
hole plug to insert the brake disc wear indicator will
cause the loss of some of this oil. Advance planning
will help to minimize oil loss.
Consider scheduling front brake disc wear inspections
along with the recommended 1000 hr. change of hy-
draulic oil and filters. Rear brakes should be inspected
for wear whenever the rear tires are removed. Also
consider obtaining additional brake disc wear indica-
tor tools for permanent installation on truck. If all brake
assemblies are equipped with disc wear indicators,
future checks will not require installation and removal.
Before removing test port plugs, always bleed
down hydraulic steering and brake accumulators.
The steering accumulators can be bled down with
engine shut down, turning the key switch "Off" and
waiting 90 seconds. Confirm the steering pressure
is released by turning the steering wheel - No front
wheel movement should occur.
Open bleed down valves located on the brake
manifold. This will allow both accumulators for the
rear brakes and both accumulators for the front
brakes to bleed down.
Before disabling brake circuit, be sure truck
wheels are blocked to prevent possible roll-away.
J5-2
FIGURE 5-2. BRAKE WEAR INDICATOR
1. Cover
2. Indicator Pin Face (Ref.)
3. Housing Face (Ref.)
4. O-Ring
Removal/Installation
1. Place the selector switch in NEUTRAL, apply the
park brake, turn the rest switch ON, turn the key
switch OFF and allow the steering accumulators
to bleed down completely. Block truck wheels.
2. Open the bleeddown valves on the brake manifold
(in the hydraulic components cabinet) and bleed
all pressure from the brake accumulators. Close
valves after pressure is released.
3. Thoroughly clean the brake assemblies, espe-
cially the area surrounding cooling oil lines.
4. Remove the hex head O-ring plug from the port
(5, Figure 5-3) next to the cooling line opposite
the cooling line (3) with the adjacent brake apply
line (2) port. Quickly insert the brake wear indica-
tor tool and tighten securely.
NOTE: The front wheel brakes have a diagnostic
connector installed for measuring brake apply pres-
sure. The rear brakes do not have a diagnostic con-
nector installed on the brake backplate, but instead
have an O-ring plug installed. Do not attempt to install
the brake wear indicator in this port.
5. Start the engine and allow the steering system to
stabilize and the brake accumulators to fill.
Disc Brake Assembly
5. O-Ring
6. Tool Housing
7. O-Ring
8. Indicator Pin
J05018 03/01