Komatsu 930E-2 Shop Manual page 426

b. Verify housing I.D. does not exceed 8.002 in.
(203.25 mm).
c. Check dimensions frequently during honing
operation to prevent removal of too much ma-
terial. Do not hone gland seal area.
4. If housing defects can not be removed within the
above limits, replace the housing.
Repair of the housing by welding, machining or
plating to salvage a worn area is NOT APPROVED.
These procedures may weaken the housing and
result in serious injury to personnel when pressur-
ized.
5. Clean parts thoroughly to remove abrasive residue
after honing.
Assembly
Assemble the accumulators in a dust and lint free
area. Maintain complete cleanliness during as-
sembly to prevent possible contamination.
1. Install a new seal (8, Figure 6-4) on piston. Install
new bearings (7). Coat seal and bearings with a
small amount of petroleum jelly.
2. Install the piston with the concave side toward gas
end (gland end) of accumulator cylinder housing
(9). Push the piston to the center of of the housing.
3. Install new O-rings and backup rings (5) on gland
(4). Coat seals with a small quantity of type C-4
hydraulic oil.
4. Install gland and tighten to 850 ft. lbs. (1152 N.m)
torque using tool as shown in Figure 6-5.
5. Install charging valve (3) with new O-ring. Tighten
charging valve large hex nut to 16.5 ft.lbs. (22.3
N.m) torque.
6. Install pressure switch. Install pressure test fittings
in bottom of housing. (See "Testing" below.)
L6-4
TESTING
To carry out the testing required, it will be necessary
to check for internal and external leaks at high pres-
sure. A source of 5000 psi (35 MPa) hydraulic pressure
and nitrogen pressure of 1400 psi (9.65 MPa) will be
required. A small water tank with the necessary safety
guards in place will be necessary for a portion of the
test.
Do not stand near gland during test procedure. A
box enclosure made of heavy steel plate is recom-
mended to contain the accumulator during oil
pressurization test.
1. Fill each end of the accumulator with approxi-
mately 8.5 gallons (32.2 Liters) of clean type C-4
hydraulic oil. Install an adaptor on the oil end to
connect to hydraulic power source. Plug remain-
ing ports.
2. Release pressure and remove oil side fitting.
3. Drain oil. Leave port open.
4. Pressurize gas end of accumulator with approxi-
mately 100 psi (690 kPa) nitrogen pressure to
move piston to bottom of housing.
5. Submerge oil end of assembly in water.
6. Apply 1400 psi (9.65 MPa) nitrogen pressure to
gas end and observe for 20 minutes. No leakage
(bubbles) is permitted.
7. Release nitrogen pressure and remove assembly
from water.
8. Drain any remaining oil or water.
9. If the accumulator is to be placed in storage, add
3 pints (1.5 L) of rust preventive oil in the nitrogen
side of the accumulator. Add 1 pint (0.5 L) in the
oil side. If the accumulator will be used immedi-
ately, type C-4 hydraulic oil may be used instead
of rust preventive oil. Plug all open ports.
10. Verify all warning and caution labels are at-
tached and legible (Refer to parts book if re-
placements are required).
Steering Circuit Component Repair
a. Apply 5000 psi (35 MPa) oil pressure.
b. Verify no external leakage exists.
c. Verify no structural damage exists.
L06021