HYDRAULIC SYSTEM GRT880 SERVICE MANUAL
2-32
Published 10/19/2017, Control # 618-00
Checking the Service Brake Accumulator
Charging Valve Pressure
1. With engine off, discharge all of the pressurized fluid
stored in the accumulators by depressing the service
brake pedal on the cab floor 12 to 15 times.
2. Install pressure check diagnostic quick disconnect
(9999101806) with gauge onto test nipple at the brake
accumulators (see Figure 2-11).
3. Start engine and idle. The charging valve will
immediately start to charge the accumulators. Watch the
pressure gauge, the high charge limit should read
2320 +72/-145 psi (160 +5/-10 bar) (when the pressure
stops rising).
NOTE: Accumulator charge valve is non-adjustable.
If the pressure is under specification and the valve does
not stop charging, perform the pressure check in the
procedure Checking the Service Brake Accumulators
Pre-charge, page 2-33, then repeat this procedure.
If after performing the procedure Checking the Service
Brake Accumulators Pre-charge, page 2-33, the valve
does not charge to the high charge limit specification,
turn the accessory manifold pressure reducing valve
clockwise a half turn at a time (see Figure 2-9) and
repeat step 3. It may require adjusting the accessory
manifold pressure reducing valve by a half turn several
times before the pressure is set high enough to allow the
brake valve to fully charge.
4. With the engine still at idle, repeatedly depress the
service brake pedal on the cab floor until the gauge
pressure reads approximately 2100 psi (145 bar). Once
this pressure has been attained, push the brake pedal
again. The recharge cycle should start again (this could
take two pedal applications). Watch the gauge and verify
the low charging limit (the pressure at which the valve
begins to charge) to be 1950 ±145 psi (134 .±10 bar).
5. Stop engine. Remove the pressure gauge.
Reference Only
To Next Page
Loading...
Need help?
General
