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Owner Service 19
MAN0450 (10/28/2005)
OWNER SERVICE
The information in this section is written for operators
who possess basic mechanical skills. If you need help,
your dealer has trained service technicians available.
For your protection, read and follow the safety informa-
tion in this manual.
Keep hands and body away from pressurized
lines. Use paper or cardboard, not hands or other
body parts to check for leaks. Wear safety goggles.
Hydraulic fluid under pressure can easily penetrate
skin and will cause serious injury or death.
Make sure that all operating and service person-
nel know that if hydraulic fluid penetrates skin, it
must be surgically removed as soon as possible by
a doctor familiar with this form of injury or gan-
grene, serious injury, or death will result. CON-
TACT A PHYSICIAN IMMEDIATELY IF FLUID
ENTERS SKIN OR EYES. DO NOT DELAY.
Before working on backhoe, extend boom and
dipperstick and place bucket on ground. Make sure
that all system pressure has been relieved by oper-
ating controls before maintenance, service, or dis-
connecting any hydraulic lines.
Always wear relatively tight and belted clothing
to avoid getting caught in moving parts. Wear
sturdy, rough-soled work shoes and protective
equipment for eyes, hair, hands, hearing, and head;
and respirator or filter mask where appropriate.
HYDRAULIC HOSES AND FITTINGS
IMPORTANT
■ Fittings with O-rings and flange do not require
additional sealant; replace damaged O-rings.
Hydraulic hoses are severely worked on a backhoe.
Examine them daily and replace if necessary. Hose
routing is very important. Make certain hoses can move
freely, without kinking, and cannot be damaged or cut
by backhoe action.
When tightening hoses and fittings, always use two
wrenches: one to hold hose and one to tighten fitting.
This will prevent hose from twisting and kinking.
Always back lock nut off and screw fitting all the way in
for fittings that use O-rings for sealing. Then hold in
position and tighten lock nut.
RELIEF VALVE
BH70-X
This valve is pre-set at the factory to prevent system
pressure from exceeding 2030 psi. Do not attempt to
reset the valve for open-center hydraulic systems. If
valve is malfunctioning, replace it with an authorized
factory replacement part or have service done by a
qualified dealer.
Figure 10. Relief Valve, BH70-X
BH80-X
This valve is pre-set at the factory to prevent system
pressure from exceeding 2470 psi. Do not attempt to
reset the valve for open-center hydraulic systems. If
valve is malfunctioning, replace it with an authorized
factory replacement part or have service done by a
qualified dealer.
Figure 11. Relief Valve, BH80-X
CAUTION