ing the complete spool assemblies and the four (4) O-
rings and spring in the dual circuit supply (dual check)
Refer to Fig. 10 for numbers in parentheses.
Remove the screws from the cover plates (1)
(four screws in each plate).
Carefully pull on the knobs to remove their
respective spools from valve body.
Cross Section of Dual Circuit Supply
1. Plate Cover (2)
2. Knob Control
3. Valve Spool
4. Valve Shuttle
5. Spring Return
Remove roll pins which retain the control knobs
on spool stems. The cover plates (1) can then
The dual circuit supply (double check) valve,
located in the tractor control (parking brake)
body i disassembled by grasping the web in the
top of the valve spool (3) with a narrow nose
pliers, twist and pull the valve spool out.
The shuttle (4) should also come out with the
Remove the shuttle return spring (5) and O-rings
(6), (7), (8) and (9).
CLEANING AND INSPECTION
The acetal components which comprise most of the
parts of the MV-2 valve should not be immersed in any
solvent type cleaner. Old lubricant should be wiped off
parts to be reused and the bores of the body wiped out
with a clean dry cloth.
Lubricate O-rings, bore and sliding surfaces with
lubricant listed in LUBRICANT SPECIFICATIONS, Item
Place the shuttle return spring (5) in the dual
circuit supply valve bore in the body.
Install O-rings (6) & (7) on the shuttle (4), and (8)
and (9) on the valve spool (3).
Insert the small end of the shuttle in the spool
and insert the assembly into the valve bore, flush
with top of body. The dual circuit supply valve
spool is retained in the body by the same cover
plate which also retains the tractor control
(parking brake) spool.
New service replacement spools will be
Place cover plates over each plunger stem. The
cover plates are identical and are installed
convex side up.
Place the red knob on the longer spool (for trailer
air supply), matching the groove in the knob with
the tongue in the cover plate (where applicable),
and secure with the roll pin.
Place the yellow knob on the shorter spool (for
tractor air supply), matching knob and cover
(where applicable) and secure with the roll pin as
before. A new roll pin will be found in each spool
Insert the shorter spool assembly with yellow
knob in the tractor supply bore (housing with the
dual supply valve). If the entire valve assembly
has been removed, position the assembly so
that the tractor control body housing is at 3
oclock. With the open bore (trailer supply) at 9
oclock, rotate the button until wording on top-
center is horizontally readable. The stepped side
of the cover plate should be covering the dual
supply valve. Secure the plate with the four flat
head Phillips screws; torque to 2.Nm (25 in. lbs.
CTS - 4079 - CHAPTER IX - Page 10