Bush Hog CBH70, CBH80, CBH60 manual Service, Beginning of Season, Bleeding Backhoe Hydraulic System

SERVICE

! CAUTION

To avoi d p ossible injury, observe t he following safety rules WHEN SERVICING the backhoe:

1. ENGAGE safety locks as shown in Fi gures 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. ESCAP ING F LUID u nder
pressure ca n have suffic ient
force to penetrate the		ski n
and cause serious i	njury. Be
sure to relieve all	pres sure
before di sco nnect ing line s.
Be sure all connections are tight and that lines, pipes
and hoses are not damage			d b efore ap plying pres-
sure to the system.
5. FLUID ESCAPING from a very small hole can be
almost invi sible. Use a		small pie ce of cardboard or
wood - not your hands - to s earch for suspected
leaks.
6. SEE A DOCTOR AT ONCE if injured by escaping
fluid. Serious in fection or			gangrene can develop if
proper medical treatment is not administered immedi-
ately.
7. PROTECT Y OUR EYES - Wear safety gla sses.
Guard against injury when d riving 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 r eplace,
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 tee th a nd, if neces sary, sharpen or
replace them.
Operate the backhoe slowly for a s hort time before
placing the unit under full load.
Bleeding Backhoe Hydraulic System
If the hydraulic hoses have			been disconnected from
the bac khoe or tractor,			all trapped air must be

removed after the hoses are connected. Start tractor engine and operate b ackhoe through all movemen ts fully several times to purge the system of air.

15

Hydraulic System Hoses
Oil leaks in t he pressure side of the system can be
located by carefully i nspecting the extern al area of
the hoses and fittings.		stem for leaks by
Check the return s ide of the sy
examining the oil in the reservoir. If air is being drawn
into t he system, the oil wi ll contai n a ir bu bbles and
appear to foam.		ways		us e t wo
When ti ghtening connections, al
wrenches.
IMPORTANT: Do not over-tighten fittings. Make them
just tight enough to eliminate leaks.			ad fittings.
NEVER use tefl on tape on pipe thre
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 sho w signs o f failure. Pay car eful atte ntion
to the r outing 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 pu mp systems, maintain the reservoir oil at
the p roper level by loo king at t he di pstick. T he di p-
stick/breather cap is located directly behi nd the right
side of the f	oot plat form on the backhoe. When
checking o il le vel, the back hoe s hould b e ext ended
to full reach with the bucket rolled back an d resting
on the ground . All cylinders a re retracted except for
the boom cylinder. Do no t 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 tracto r engine. Drain o il
from reservoi r and replace drain plug.			Refill reser -
voir with 4 ga llons of fres h oil followi ng g uide-
lines 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 h ydraulic sys tem, check oil level in				reservoir
with backhoe extended to full reach and bucket rolled
back and rest ing 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 oi l may be
forced out th	rough breather ca	p during bac khoe
operation.

If th e tracto r syste m su pplies the hydr aulic pow er, service according to the tractor instruction manual.