Operation and maintenance manual

Section 250-0070
SM 2165 Rev 1 11-03
5
11. With valve assembly horizontal, remove capscrews
and separate pilot valve body (8) from upper valve
body (9). Remove capscrews (10) and separate lower
valve body (11) from upper valve body (9).
12. With the pilot valve body (8) upright on the work
bench, hold with one hand and push the actuator
piston (7) down with the other hand until piston guide
(6) pops loose.
13. Turn pilot valve body (8) on its side on the work
bench and remove piston guide (6) and actuator piston
(7) from pilot valve body (8).
14. Remove glyde ring assembly (20) from actuator
piston (7).
15. Remove 'O' rings (21, 23 & 26), backup rings (22,
25 & 27) and Polypak seal (24) from piston guide (6)
and discard.
16. Turn upper valve body (9) on its side on the work
bench and remove piston return spring (19), regulator
spring (18), spring seat (17) and upper regulator spool
(16) from upper valve body (9).
17. Turn lower valve body (11) on its side on the work
bench and remove lower regulator spool (14) and
spool return spring (13) from lower valve body (11).
Remove and discard 'O' ring (15) from counterbore in
lower valve body (11).
18. Secure lower valve body (11) upright in a table vice
and remove plug (12) and 'O' ring from lower valve body
(11). Discard 'O' ring. Remove lower valve body (11)
from the vice.
INSPECTION
Numbers in parentheses refer to Fig. 1.
1. Clean all parts with a suitable cleaning solvent.
2. Inspect actuator piston (7) and piston guide (6) for
damage and wear. If axial grooves are seen or if any
wear is evident, replace actuator piston (7) and piston
guide (6) as a matched set.
3. Lightly lubricate regulator spools (14 & 16). Place
upper and lower regulator spools (14 & 16) into
corresponding regulator bore in valve body and push
the spool lightly through the bore. Each regulator spool
must be able to move freely and smoothly the entire
length of the regulator bore. If it cannot, regulator
spool and valve must be replaced as a matched set.
Note: Never replace just the spool or valve. 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 replaced.
Also, if the treadle valve was not reaching proper
regulated pressure, replace all regulator springs.
5. Inspect threaded inserts in actuator cam, actuator
base (3) and pedal assembly (1). If any of the threads
are damaged, the inserts must be replaced.
6. Clean pilot valve body (8) thoroughly to remove all
residual adhesive or particles of boot (5). Using a knife
or suitable scraper, thoroughly clean the sides of pilot
body (8) by scraping the lip where the pilot body
contacts the boot (5).
SUB-ASSEMBLY
Numbers in parentheses refer to Fig. 1.
Note: All metal parts should be thoroughly cleaned
with a suitable solvent, dried, and lubricated with a
light weight oil before assembly. This valve is built to
extremely close manufacturing tolerances. Great care
should be taken to keep components protected from
contamination prior to and during assembly.
Threaded Inserts
1. Position actuator base (3) upside down on the work
bench and support directly under each of the four floor
mounting holes. Install threaded inserts into actuator
base (3) by tapping lightly with a small hammer until
insert flanges become flush with actuator base (3). Be
sure actuator base (3) is supported to prevent
breaking. Thoroughly clean actuator base (3)
assembly and set aside.
2. Position actuator cam upside down on the work
bench and support it at the centre hole. Insert
threaded insert by tapping lightly with a small hammer
until its flange becomes flush with actuator cam
surface. Be sure actuator cam is supported to prevent
breaking. Thoroughly clean actuator cam assembly
and set aside.
3. Position pedal (1) upside down on the work bench
and support it directly above the two holes near its
centre. Install threaded inserts by tapping lightly with a
small hammer until their flanges becomes flush with
pedal (1) surface. Be sure pedal (1) is supported to
prevent breaking.
4. Install oval point screws into inserts and screw down
Braking System - Treadle Valve