Bush Hog BH850 Lawn Mower User Manual


 
Hydraulic System Hoses
Oil leaks in the pressure side of the system can be
located by carefully inspecting the external area of
the hoses and fittings.
Check the return side of the system for leaks by
examining the oil in the reservoir. If air is being drawn
into the system, the oil will contain air bubbles and
appear to foam.
When tightening connections, always use two
wrenches.
IMPORTANT: Do not over-tighten fittings. Make them
just tight enough to eliminate leaks.
NEVER use teflon tape on pipe thread fittings.
Always use a paste-type sealer.
Hoses on any backhoe are very severely worked and
will fail in time. Examine them regularly and replace
any that show signs of failure. Pay careful attention
to the routing of hoses so they can move fully and
freely without kinking, and cannot be pinched or cut
by any part of the backhoe.
Hydraulic System Reservoir
On PTO pump systems, maintain the reservoir oil at
the proper level by looking at the dipstick. The dip-
stick/breather cap is located directly behind the right
side of the foot platform on the backhoe. When check-
ing oil level, the backhoe should be extended to full
reach with the bucket rolled back and resting on the
ground. All cylinders are retracted except for the boom
cylinder. Do not overfill; oil may be forced out of the
breather cap.
Fill with:
SAE 10W40 engine oil with API “SF/SG” classifica-
tion in northern climates.
SAE 40W engine oil with API “SF/SG” classification
in southern climates.
Change oil every 200 hours or more often if neces-
sary. To change oil, extend backhoe to full reach with
bucket rolled back and resting on ground. Turn off
tractor PTO and shut down tractor engine. Unseat
breather cap from fill tube and remove drain plug
from left rear underside of hydraulic reservoir using
1/4” hex wrench. Drain oil from reservoir and replace
drain plug. Refill reservoir with 7 gallons of fresh
oil following guidelines listed above for proper oil
selection. Reseat breather cap and start engine and
PTO. After cycling all backhoe functions several
times to remove any air from hydraulic system, check
oil level in reservoir with backhoe extended to full
reach and bucket rolled back and resting on ground.
If oil level on dipstick is below “ADD” line, add
enough oil to bring level up to “FULL” line. DO NOT
overfill reservoir or oil may be forced out through
breather cap during backhoe operation.
If the tractor system supplies the hydraulic power,
service according to the tractor instruction manual.
14
SERVICE
CAUTION
To avoid possible injury, observe the following
safety rules WHEN SERVICING the backhoe:
1. ENGAGE safety locks as shown in Figures 1 & 3
before servicing the backhoe.
2. DO NOT oil, grease or adjust the backhoe while it
is in motion.
3. DO NOT change any backhoe relief valve settings.
They are factory set for best performance and safety.
4. ESCAPING FLUID under
pressure can have sufficient
force to penetrate the skin
and cause serious injury. Be
sure to relieve all pressure
before disconnecting lines.
Be sure all connections are
tight and that lines, pipes and hoses are not dam-
aged before applying pressure to the system.
5. FLUID ESCAPING from a very small hole can be
almost invisible. Use a small piece of cardboard or
wood - not your hands - to search for suspected
leaks.
6. SEE A DOCTOR AT ONCE if injured by escaping
fluid. Serious infection or gangrene can develop if
proper medical treatment is not administered immedi-
ately.
7. PROTECT YOUR EYES - Wear safety glasses.
Guard against injury when driving connecting pins or
performing any repair in which particles can chip
from work piece or striking tool.
BEGINNING OF SEASON
Remove all protective coverings.
Check hydraulic hoses for deterioration and replace,
if necessary.
Lubricate all grease fittings and oil handle linkages.
Check hydraulic system for loss of fluid and, if neces-
sary, fill to proper level.
Tighten all loose bolts, nuts and setscrews.
Inspect bucket teeth and, if necessary, sharpen or
replace them.
Operate the backhoe slowly for a short time before
placing the unit under full load.
Bleeding Backhoe Hydraulic System
If the hydraulic hoses have been disconnected from
the backhoe or tractor, all trapped air must be
removed after the hoses are connected. Start tractor
engine and operate backhoe through all movements
fully several times to purge the system of air.