Komatsu 830E, Shop Manual

Page: 348 / 783

NOTE: Throughout the following steps, it is important
to keep the circuits and circuit components identified
as to which side of the unit they came from. For a given
circuit, all the components have a tolerance stack
which could vary. Keep the “B1” and “B2” parts sepa-
rate. Springs (8 & 9) are also different in “B1” and
“B2” bores.
21. Remove the spools (12), reaction plungers (21, 22)
and spool return springs (20) from the regulator
sleeves (19).
22. Remove the plunger return springs (10), regulator
springs (8 & 10), and spring seats (11) from the
valve body.
23. Remove the actuator plungers (3) by pushing
down (toward the bottom of the valve) on the
actuator plunger with your hand until the actuator
plunger slides out.
24. Remove the staging seat (6). Remove and discard
packing (5).
25. Remove the glyde ring assembly (7) from the
actuator plunger.
26. Remove the O-rings (14, 16 & 18) and teflon
back-up rings (13, 15 & 17) from the regulator
sleeves and discard.
27. Remove the wiper seals (23), poly-pak seals (25),
and the orange back-up rings (24) from the actua-
tor section of the valve and discard.
Cleaning and Inspection
1. Clean all metal parts with solvent and air dry.
2. Inspect the plunger (3, Figure 3-5) for wear on the
sides where it moves through the seals. If axial
grooves are seen or if any wear is apparent,
replace the plunger. Plungers with diameter worn
below 0.747 in (18.974 mm) must be replaced.
3. Place the regulating spool (12) into its sleeve (19).
Push the spool lightly through the sleeve. The
spool must be able to move freely and smoothly
the entire length of the sleeve. If it cannot, it must
be replaced. Never replace just the spool or
sleeve. They must be replaced as a matched set.
4. Inspect each spring carefully for cracks or breaks.
Any spring with a crack or break must be re-
placed. Also, if the valve was not reaching proper
regulated pressure, replace all regulator springs.
5. Inspect the threaded inserts (7, Figure 3-4) in the
actuator base. If any of the threads are damaged,
the inserts must be replaced.
6. Lubricate all parts with a thin coat of clean type
C-3 hydraulic oil. Take care to keep components
protected from contamination.
ASSEMBLY
Actuator Base Threaded Inserts
1. If any inserts (7, Figure 3-4) were removed from
the actuator base (6), position the actuator base
upside down on the work bench and support
directly under each of the four floor mounting
holes.
2. Install the threaded inserts into the actuator base
by tapping lightly with a small hammer until the
insert flanges become flush with the actuator
base. Be sure the base is supported to avoid
breaking the base.
3. Thoroughly clean the actuator base and set aside.
Boot and Cap
1. Examine the boot (2, Figure 3-4) for any cracks,
tears, or other damage. If damage is evident, the
boot must be replaced To replace the boot, follow
the procedure below.
2. Remove the boot from the actuator cap (1) and
discard the old boot. Thoroughly clean the sides
of the cap by scraping the lip where the cap
contacts the boot. Use a knife or suitable scraper.
Clean thoroughly to remove all residual adhesive
or particles of the old boot.
3. Apply a thin bead of Loctite Prism 410 onto the
upper sides of the cap. Apply the bead to the two
long sides only. Do not apply it to the rounded
ends, these must not be sealed to allow the boot
to “breathe”.
4. Carefully position the cap into the new boot groove
wiping off the excess glue.
5. Position the boot such that it conforms to the
contour of the cap, then set aside. Adhesive
requires about 30 minutes to cure.
J3-6 Brake Circuit Component Service J03022 1/99