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Bosch Rexroth Corp.
Industrial Hydraulics
RA 17 041-DT4SM/06.09
Service Manual for CDT4-CDG4
Seal Replacement
General:
1. Always drain the pressure from a hydraulic system before per-
forming any service work. Disconnect hydraulic lines from head
and cap ports of cylinder.
2. Completely disassemble the cylinder using the exploded and
assembly views as reference. No special tools are required ex-
cept internal snap ring pliers. The piston rod assembly consisting
of piston, piston rod and head cushion bushing (where used) are
locktited and secured at the factory and are not to be disas-
sembled.
3. After disassembling the cylinder, wash all metal parts in a
non-fl ammable solvent. Rinse each part thoroughly and blow dry
with a low-pressure air jet. Arrange the parts on a clean surface.
Examine each part carefully. Replace all seals and any other
worn or damaged parts.
4. Particular attention should be given to the piston rod (item 10)
since cylinder leakage can result from a damaged rod. A scored
rod might damage the rod bearing and, subsequently, the rod
packing. Rod cartridge kits come with a new rod bearing plus
seals (see Seal Kit table on page 6 of this manual.)
Old Rod Cartridge Kit Removal
1. Remove the hex head bolts (item 15) from the head end (item
1). On the ME5 mount only, the rod cartridge retainer plate is
held in place by socket head cap screws, which must also be
removed.
2. Remove the retainer plate or fl ange (item 5) from the head end.
Locate the screwdriver slot along the top of the rod bearing (item
16). Using a fl athead screwdriver, carefully pry the rod cartridge
loose from the head in a fashion similar to opening a can of paint.
The rod bearing assembly includes the wiper (item 19a), the rod
seal (item 19b), the bearing o-ring and backup ring (items 19c-d),
and the rod bearing (item 16) itself.
New Rod Cartridge Kit Installation:
1. Lubricating the new rod bearing will ease installation into the
head end. A rubber mallet may be required to push the rod bear-
ing into the head end. Caution must be taken to not cut the new
seals when passing the bearing over a male threaded rod.
2. Once the rod bearing is completely seated in the head end, the
fl ange or retainer plate and tie rod nuts / hex head cap screws
can be replaced onto the head end. Torque the bolts / screws to
the specifi cations on page 3.
Piston Seal Installation:
1. Insert the energized piston seal o-ring onto the piston in the
center groove. Do not roll the o-ring; rather, slide it into place.
Slide piston seal into the center groove, directly over top of the o-
ring. Heating the piston seal in 175°F to 212°F warm oil or water
would assist in installation by hand. While still warm, the piston
seal can be reshaped by means of a ring compressor or other aid.
Courtesy
of
CMA/Flodyne/Hydradyne
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Motion
Control
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Hydraulic
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Pneumatic
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Electrical
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Mechanical
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(800)
426-5480
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www.cmafh.com
