JLG 1100S Service Manual - Manual (Page 271)

SECTION 5 - HYDRAULICS
3121256 – JLG Lift – 5-49
9. Remove the spring cover hex cap for the ”outer”
flow regulation adjustment this requires a 19-mm
wrench.
10. Remove the spring disc.
11. Remove the adjusting springs (two springs, one
”nested” inside the other) and spring follower.
12. The flow regulation spool should slide from the con-
trol housing, (a magnet should aid in removal). If it
does not, remove the hollow hex head plug at the
rear of the flow regulation spool and carefully push
the spool from the housing - do not scratch/mar the
spool’s bore.
13. Remove the spring cover hex cap for the ”inner”
pressure compensation adjustment – this requires a
30-mm wrench.
14. Remove the spring disc.
15. Remove the adjusting springs (two springs, one
”nested” inside the other).
16. Remove the spring follower.
17. The pressure compensation spool should slide from
the control housing, (a magnet should aid in
removal). If it does not, remove the hollow hex head
plug at the rear of the flow regulation spool and
carefully push the spool from the housing - do not
scratch/mar the spool’s bore.
18. The spools are identical.
19. Wash the housing and all parts in a clean JLG
approved solvent such as non-chlorinated brake
cleaner, Stoddard solvent, etc.
20. Blow off all the parts with clean, dry compressed air.
21. Inspect the housing for contamination or plugged
orifices. Clean orifices carefully with a dead soft steel
wire to insure they are open. Inspect all parts for
burrs, scoring, debris, etc.
NOTE: On the mounting surface of the control housing,
between the oil ports is what appears to be a slotted
head screw. IT IS NOT A SCREW. This is a bleed
orifice, which must be orientated to allow proper con-
trol operation. The slot in the head should be ori-
ented to fall in-line with the oil ports, NOT
PERPENDICULAR to the oil ports. If the slot is ori-
ented perpendicular to the three ports, the pump
pressure will not return from load pressure to stand-
by pressure at the end of operating a function! The
pump pressure will remain at the last highest pres-
sure generated.)
22. After all parts are clean and dry, lightly oil a control
spool and install in its bore. The spool must slide
smoothly and easily within the housing. If it does
not, check for contamination. If contamination can-
not be found check for ”scoring” or ”burring” of the
control housing. If the spool does not slide smoothly
& freely, the control must be replaced with a new
unit.
23. Lightly oil and check operation of the second spool.
The spools are installed correctly when there
”pointed” end faces the spring followers
24. Re-assemble in reverse order.
25. Bench set the pressure adjustments.
NOTE: The pump control can be equipped with either O-
rings or a sealing plate. These components are NOT
interchangeable.
26. Re-install on the Function Pump, insure the ”0”-rings
are installed properly and tighten the four (4) M6
socket head cap screws to 105 inch pounds.