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Service & maintenance instructions for gas spring models:
CU 1000, CU 1800, CU 2900, CU 4700, CU 7500,
CU 11800, CU 18300
T-handles
Charging
armature
Lock ring
tool
Valve tool
Charging
adapter
Box 216, 573 23 Tranås, Sweden
Tel +46 140 571 00, Telefax +46-140-571 99
www.kaller.com
8100-2022-02
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SERVICE INSTRUCTION
J
H
G
F
E
K
D
C
B
A
L
A) Bottom
B) Lock ring
C)* Back-up ring
D)* O-ring
E) Tube
F)* Piston seal with O-ring
G)* Wear ring
H)* Scraper
J) Piston
K)* Valve
L)* Cover screw
* = Parts included in the repair kit
Warnings
z PED designed gas springs whose tube
and bottom are marked with a circular
ring have internal components which
differ from the design of the previous
model. Therefore you must never mix
PED and non-PED gas spring
components
together when servicing the spring.
z Always read the permanently marked
information on the side of the tube before
servicing to make sure you use the
correct Repair Kit.
z Failure to exhaust all gas pressure prior
to disassembling could result in serious
injury.
z The maximum charging pressure is 150
bar (2175 psi).
z Use only pure nitrogen gas, N
charging.
z Always wear safety goggles, when
servicing the gas spring.
for
2
z Only specially trained personnel with good
knowledge about the products should carry
out the maintenance.
z Once the cover screw is removed, never
lean directly over the valve. Always direct
the valve port away from yourself and
others.
z Never use extreme force on the gas spring.
Charged gas springs are under high
internal pressure and should be protected
against damage.
z Always use protective jaws when clamping
the spring in a vice.
z To achieve maximum service life, keep the
gas spring protected from dirt, drawing
fluids, and grinding dust.
For more information, also refer to
the“Instructions for service and maintenance of
KALLER Gas Springs”, Part No. 8100-2000.
Disassembly
1) Clamp the gas spring in a vice (fitted with
protective jaws). Unscrew the G 1/8" cover
screw (L) with a 5 mm Allen key.
If there is no gas left in the spring the
bottom (A) may rotate. If so, gently fasten
the tube at its lower end to clamp the
bottom slightly.
2) If there is still gas pressure in the spring,
release it by screwing the threaded end of
the valve tool into the charging port until
the valve needle opens. The valve (K) must
not be unscrewed until the bottom can be
pushed in by hand or be tapped in using a
plastic mallet. Then unscrew the valve with
the opposite end of the valve tool and
remove the valve using the needle nose
pliers.
3) Tap in the bottom (A) using a socket and
mallet until the lock ring (B) is exposed.
Remove the lock ring with the lock ring tool
(the tool with the concave tip). Bend the
lock ring upwards and inwards.
4) Pull out the bottom (A), using the
T-handle and then pour out the remaining
oil.
5) Clamp the gas spring in the vice with the
piston facing upwards and tap out the
piston (J) using socket and plastic mallet.
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SERVICE INSTRUCTION
6) Remove the piston seal (F) and the guide
ring (G) from the piston.
Note! Be careful not to damage the
piston seal groove when removing the
seal.
On smaller models it can be difficult to
remove the seal by hand. If so, lift the seal
and cut it loose using a sharp knife.
7) Remove the scraper (H) from the tube.
Please note! The same repair kit is used for
all stroke lengths of the CU 1000 and it
should always be repaired from the bottom
as the separate guiding for stroke lengths
32 - 50 mm is not removable.
8) Next, remove the O-ring (D) and the
support ring (C) from the bottom.
Inspection
9) Clean the tube, piston and bottom.
10) Closely inspect the inside of the tube and
the sealing grooves on the piston and
bottom. There should be no scratches or
dents on the inside surface of the tube, the
piston or the lock ring grooves. If these
parts are scratched or damaged in any way,
then they should be replaced.
15) Clamp the tube with the lock ring groove
facing upwards securely in the vice. Oil the
seals on the piston and the upper part of
the tube. Fit the piston by pressing it into
the tube and then tapping it down carefully,
using a socket and plastic mallet. Making
sure all of the stroke length becomes
exposed.
16) Fill the spring with the appropriate amount
of oil (see table below).
ledoM liO
mm52-6ekorts,0001UClm2
mm05-23ekorts,0001UClm4
mm52-6ekorts,0081UClm4
mm05-23ekorts,0081UClm8
mm52-01ekorts,0092UClm4
mm05-23ekorts,0092UClm8
mm52-01ekorts,0074UClm6
mm05-23ekorts,0074UClm01
mm52-01ekorts,0057UClm01
mm05-23ekorts,0057UClm51
mm52-01ekorts,00811UClm02
mm05-23ekorts,00811UClm04
mm52-01ekorts,00381UClm03
mm05-23ekorts,00381UClm05
Assembly
11) Unpack the repair kit. Check to make sure
all parts are contained in the kit by
comparing the contents to the picture in
this service instruction. Discard all parts
that are to be replaced with new ones from
the repair kit.
12) First fit the scraper (H) into the top of the
tube. Make sure the scraper sits correctly in
the groove with the lip pointing upwards.
13) Clamp the piston in the vice and mount the
guide ring (G) and the piston seal(F) with
the O-ring facing downwards (nitrogen
side).
14) Mount the support ring (C) and the
O-ring (D) to the bottom. Note! Check that
the O-ring is fitted correctly (nitrogen side) .
Warning! When servicing a PED
designed gas spring, make sure the tube
and bottom are both either marked or
not marked with a circular ring. Do not
mix marked and un-marked
components.
17) Oil the O-ring (D) on the bottom. Tap down
the bottom (A) into the tube until the lock
ring groove is exposed using the socket
and plastic mallet.
18) Fit the lock ring (B) into the lock ring groove
by pushing one of the ends into the groove,
then either press or hit the other until it
snaps into the groove.
19) Pull out the bottom (A) using the
T-handle until the bottom and the tube are
flush.
Warning! If the bottom and tube are not
flush, the assembly is incorrect. DO NOT
charge the spring. Charging an
incorrectly assembled spring could
result in serious injury.
20) Mount the valve (K) into the charging port
using the valve tool. Tighten only finger
tight. The gas spring is now ready for
charging.
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SERVICE INSTRUCTION
Charging gas
We recommend that a replenishing armature
with pressure regulator is used
(Order No. 3415075-2000).
Z
N
GAS
2
Y
100
Bar
0
315
V
X
100
200
300
200
300
Bar
0
315
U
P
N
O
Q
R
M6
P
S
G 1/8” charging adapter,
3014016, valid for
CU 1800 to CU 18300
T
N
0
21) Check that the evacuating valve (P) and the
shut-off valve (Q) are closed (turn in a
clockwise direction). The release pin (S)
should be inside the M6 thread on the
armature (turn knob (O) in a counter-clockwise direction).
22) Check that the M6 thread at the end of the
armature is equipped with the sealing
washer (R).
For G 1/8” port: connect G 1/8” adapter
3014016 to the replenishing armature.
23) Connect the replenishing armature to the
gas spring, by means of knob (N), turned in
a clockwise direction.
24) Open the Nitrogen bottle using knob (Z).
Regulate to the desired charging pressure
with handle (U) on the regulator (V).
Note! maximum charging pressure is
150 bar (2175 psi).
The manometer (X) shows the charging
pressure and manometer (Y) shows the
bottle pressure.
25) Open the shut-off valve (Q) slowly on the
armature and charge as slowly as
possible. After charging, the manometer (T)
shows the pressure supplied to the gas
spring.
26) After charging, empty the gas inside the
armature by first closing the shut-off valve
(Q) and opening the bleed valve (P) until
the gas is released.
27) Unscrew the armature fully using knob (N).
Check to make sure that the valve does not
leak. If the valve is leaking, it must be
replaced. For safety, never lean over the
valve!
28) Fit the cover screw (L) on the gas spring,
tighten with 2 Nm for M6 cover screw and
5 Nm for G1/8” cover screw. Note that it has
a sealing function and must always be fitted
and tightened.
29) When finished with the armature, empty the
gas inside the armature and hose by
closing the nitrogen bottle using knob (Z)
and opening bleed valve (P) and shut-off
valve (Q) until all gas is released.
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