Allmand Brothers Allmand 7.5 FT BACKHOE - Manual (Page 15)

15
POSSIBLE CAUSE CORRECTIVE ACTION
17
Oil leakage past spool
seal into spool cap
If spool cap contains oil, replace spool
seal o-ring. If o-ring retainer is “belled”
check for restriction from “out” port
reservoir. See item 30.
18 Broken return springs Replace springs. See item 30.
19 Bent spool.
Return for factory repair or replace with
new spool section. See item 30.
20 Foreign particles. Clean system and valve.
21
Misalignment of control
handle linkage or spool
bonnet. Check linkage for binding condition;
loosen bonnet, operate valve to realign,
and retighten.
22
Spool not moved to full
stroke. Spool travel should be 5/16" either way or
5/8" total. See item 30.
23
Relief valve setting in
control valve too low or
defective. Clean or overhaul relief valve or replace
cartridge. Refer to VALVE SERVICE
section for proper PSI settings
24
Overload relief valve in
control valve stuck open
or malfunctioning.
Clean relief. Do not disturb pressure
setting or replace cartridge.
25 Worn control valve. Replace control valve.
26
Check poppet in control
valve not holding.
Clean check poppet(s) carefully. Ensure
free movement and proper seating or
replace check poppet(s). See item 30.
27
Damaged or worn spool
seals.
Replace spool end seals.
28
Check ball in anti-
cavitation is stuck or not
seated properly. Clean anti-cavitation valve carefully.
Assure that checks move freely and seat
properly or replace cartridge. See item 30.
29
Valve cap and center
return mechanism
binding.
Loosen screws holding cap on valve (ref.
Item#2 P.22). Operate
valve spool and
retighten screws.
30. This valve is a precision device and is
not intended for extensive field
adjustment or repair. Field replacement
parts are limited to seal kits, cartridges,
valve sections and tie rod ends. Beyond
replacement of these parts, opening of
check cavities and certain relief valve
cavities to examine for trapped dirt, or
resetting main relief valve with the use of
a good pressure gauge, valve should be
returned for service.
Dirt and shreds of packing material are the usual
causes of valve malfunction. Be sure that oil
supply is kept clean. Use only factory supplied
packings in cylinder repair. Fittings and hoses
must be clean before being removed.
Pages 20 & 21 explain proper valve repair
procedure. Pages 22 & 23 illustrate valve and lists
repair parts.
NOTE: Pay close attention to all caution
warning notes so valve will not have to be
returned to manufacturer for reconditioning.
Troubleshooting guide is designed to help
qualified individuals, with valve service training,
correct minor problems which may develop. If
valve is under warranty do not attempt
disassembly for repairs. Contact your authorized
dealer.
HYDRAULIC TROUBLE SHOOTING