Operation and maintenance manual

Section 250-0070
Braking System - Treadle Valve
SM 2165 Rev 1 11-03
6
until 12.7 mm (0.5 in) of screws protrude below insert
flanges. Make sure that both screws are adjusted to
the same dimension.
5. If removed, install capscrews into pedal (1) and
install washers and nuts onto capscrews. Screw nuts
on flush with the ends of capscrews and set the
assembly aside.
Piston Guide
1. Install Polypak seal (24) and backup ring (25) into
seal groove of piston guide (6). See Fig. 6.
Note: Be sure Polypak seal (24) is installed so that the
internal 'O' ring will be facing the bottom of the valve
when the actuator piston (7) is installed into the upper
valve body (9).
2. Install 'O' ring (21) into seal groove above threads
on piston guide (6).
3. Apply a thin film of oil to Polypak seal (24) and outer
'O' ring seal of piston guide (6).
4. Install backup rings (22 & 27) and 'O' rings (23 &
26) into seal grooves of piston guide (6). See Fig. 6.
Actuator Piston
Note: Glyde ring (20) assembly consists of an 'O' ring
and a split glyde ring.
1. Install 'O' ring into the 'O' ring groove located at the
large diameter end of actuator piston (7).
2. Install split glyde ring over the 'O' ring. Twist and
squeeze the split glyde ring into a small circle before
installing to ensure a tight fit over the 'O' ring.
ASSEMBLY
Numbers in parentheses refer to Fig. 1.
1. Hold upper valve body (9) horizontally. Lightly
lubricate upper regulator spool (16) and insert into
regulator bore of upper valve body (9).
Note: Slide spool (16) back and forth in the regulator
bore to ensure spool will slide smoothly and freely.
Note: Remove upper regulator spool (16) from bore
and set aside for future assembly.
2. Hold upper valve body (9) upright and install spring
seat (17), regulator spring (18) and piston return
spring (19) into upper valve body (9).
3. Install actuator piston (7) assembly into piston guide
(6), hold upper valve body (9) assembly upright and
screw actuator piston (7) and piston guide (6)
assembly into upper valve body (9). Tighten piston
guide (6) assembly using a suitable spanner.
4. Secure pilot valve body (8) to upper valve body (9)
with capscrews. Tighten capscrews evenly to a torque
of 16 - 17 Nm (140 - 150 lbf in).
5. Lightly lubricate upper regulator spool (16) and
install into regulator bore of upper valve body (9)
assembly. The spherical end of regulator spool (16)
should be at the towards the top of valve body (9)
assembly.
Note: Set aside upper valve body (9) assembly for
future assembly.
6. Hold lower valve body (11) horizontally. Lightly
lubricate lower regulator spool (14) and insert into
regulator bore of lower valve body (11).
Note: Slide spool (14) back and forth in the regulator
bore to ensure spool will slide smoothly and freely.
7. Insert spool return spring (13) into regulator spool
(14).
Fig. 6 - Piston Guide Seal Installation
SM - 2406
25
27
26
24
23
22
22 - Backup Ring
23 - 'O' Ring
24 - Polypak Seal
25 - Backup Ring
26 - 'O' Ring
27 - Backup Ring