Click here to make tpub.com your Home Page

Page Title: CONTROL VALVE
Back | Up | Next

Click here for thousands of PDF manuals

Google


Web
www.tpub.com

Home


   
Information Categories
.... Administration
Advancement
Aerographer
Automotive
Aviation
Construction
Diving
Draftsman
Engineering
Electronics
Food and Cooking
Logistics
Math
Medical
Music
Nuclear Fundamentals
Photography
Religion
   
   

 

TM 10-3930-644-14&P
Include  your  purchase  order  and
full
information
J. CHECKING CONTROL VALVE INLET PRESSURES
regarding the nature of the breakdown.
In some cases where a pump is inoperative, it may be
possible to repair it in the field. Satisfactory repair can
be accomplished, provided a clean, well equipped repair
shop manned by a competent mechanic is available.
I. CONTROL VALVE
The function of the control valve is to direct the flow of
the hydraulic oil, under pressure, to the appropriate
cylinders. The control valve requires very little attention
with the exception of keeping the hydraulic lines and
hose connections tight.
There are normally, two operating plungers in the valve.
One is a single acting plunger which operates the lift
cylinder.  The other is a double acting plunger :  o
operate the tilt cylinders.
When the control lever is in "neutral" position, the oil is
being circulated through the open center of the valve
and back to the reservoir; but is not entering any of the
Figure 1-4. Relief Valve
cylinder ports.  As the control lever is moved to its
operating position, the cylinder ports begin to open and
1. Relief Valve Adjustment
the open center passage begins closing. At the extreme
limit of control lever travel, the cylinder ports are open
Whenever the control valve or hydraulic pump
and the open center passage is closed. The applied oil
has been repaired or replaced, check the relief
pressure then opens the check valve and allows the oil
valve and adjust to open at specified pressure.
to flow to and/or from the lift or tilt cylinders.
Check and adjust the relief valve (Fig i-4)
located in the lift section of the control valve as
An adjustable relief valve is Incorporated in the control
follows:
valve.  It is used to relieve extreme pressures when
maximum tilt or lift position, or overloads are reached, to
a. Gain access to the control valve; actual
prevent damage to the hydraulic system.
location varies between truck models.
1. Linkage
b. Some adapters nave a plug in them where
a pressure gauge can be installed. If unit
Improperly adjusted or out of adjustment linkage
is not equipped with this type adapter.
can result in binding or bending of the control
Disconnect the hydraulic line at the inlet
valve linkage.
port of the control valve.
Ensure that tilt and lift control levers and
c. Install a tee fitting on the end of the
associated linkage travels freely and smoothly
hydraulic line and connect the tee fittings
through forward and backward movement of
to the adapter in the inlet port.
each lever and that the control valve plungers
respond accordingly.  Adjust, repair or replace
d. Install a pressure gauge with a 0 to 3000
as is necessary.
psi range in the tee.
Be certain that pivot points or other mating
e. Place shift lever in neutral position, turn
surfaces are free of accumulated sludge and
key switch ON and start engine.
remain lightly lubricated to function smoothly.
f. the tilt lever back to retract the tilt
cylinders and hold lever in this position.
2-88

Privacy Statement - Press Release - Copyright Information. - Contact Us

Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business