Danfoss DDC20 User manual

Service Manual
Axial Piston Pumps
DDC20
powersolutions.danfoss.com

Revision history Table of revisions
Date Changed Rev
August 2017 change charge pump housing 0302
March 2015 add implement pump option CA
March 2014 Danfoss layout BA
September 2011 First printing AA
Service Manual
DDC20 Axial Piston Pumps
2 | ©Danfoss | August 2017 L1120413 | AX00000135en-US0302

Introduction Overview..............................................................................................................................................................................................4
Warranty.............................................................................................................................................................................................. 4
General Instructions........................................................................................................................................................................ 4
Remove the unit..........................................................................................................................................................................4
Keep it clean..................................................................................................................................................................................4
Lubricate moving parts.............................................................................................................................................................4
Replace all O-rings and gaskets............................................................................................................................................. 4
Secure the unit.............................................................................................................................................................................5
Safety Precautions............................................................................................................................................................................5
Unintended machine movement..........................................................................................................................................5
Flammable cleaning solvents.................................................................................................................................................5
Fluid under pressure..................................................................................................................................................................5
Personal safety.............................................................................................................................................................................5
Symbols used in Danfoss literature............................................................................................................................................6
Pressure Measurements Gauge Port Locations and Gauge Installation - with Aux Pad......................................................................................... 7
Gauge Port Locations and Gauge Installation - with Geroter.......................................................................................... 8
Gauge Port Locations and Gauge Installation - with Implement Pump.......................................................................9
Adjustments Pump Adjustment..........................................................................................................................................................................10
Standard Procedures.................................................................................................................................................................... 10
Charge Pressure Relief Valve......................................................................................................................................................10
High Pressure Relief Valve - HPRV............................................................................................................................................11
Loop Flushing Valve......................................................................................................................................................................12
Troubleshooting Overview........................................................................................................................................................................................... 13
System operating hot...................................................................................................................................................................13
Transmission operates normally in one direction only....................................................................................................13
System noise or vibration........................................................................................................................................................... 13
System will not operate in either direction.......................................................................................................................... 14
Sluggish system response...........................................................................................................................................................14
Minor Repair Charge Pump...................................................................................................................................................................................15
Implement Pump...........................................................................................................................................................................17
Shaft and Seal..................................................................................................................................................................................18
High Pressure Relief Valves - HPRV..........................................................................................................................................21
Charge Pressure Relief Valve......................................................................................................................................................22
Loop Flushing Valve......................................................................................................................................................................23
Bypass Valve.....................................................................................................................................................................................24
Optional Coupling.........................................................................................................................................................................26
Torque charts Fastener Size and Torque Chart - with Charge Pump.......................................................................................................27
Fastener Size and Torque Chart - with Implement Pump...............................................................................................27
Plug Size and Torque Chart - with Gerotor...........................................................................................................................28
Plug Size and Torque Chart - with Aux Pad..........................................................................................................................29
Plug Size and Torque Chart - with Implement Pump....................................................................................................... 30
Service Manual
DDC20 Axial Piston Pumps
Contents
©Danfoss | August 2017 L1120413 | AX00000135en-US0302 | 3

Overview
This manual includes information on maintenance, troubleshooting, and minor repair of DDC20 pumps.
Performing minor repairs may require removal from the vehicle/machine. Thoroughly clean the unit
before beginning maintenance or repair activities. Since dirt and contamination are the greatest enemies
of any type of hydraulic equipment, follow cleanliness requirements strictly. This is especially important
when changing the system filter and when removing hoses or plumbing.
A worldwide Global Service Partner Network is available for major repairs. Major repairs require the
removal of the unit’s endcap, which voids the warranty unless done by a Global Service Partner. Danfoss
Global Service Partners are trained by the factory and certified on a regular basis. You can locate your
nearest Global Service Partner using the distributor locator at www.powersolutions.danfoss.com
For more detailed informaion about DDC20 pumps, including operating parameters and technical
specifications, refer to DDC20 Technical Information Manual L1104976.
Warranty
Performing maintenance, and minor repairs according to the procedures in this manual will not affect
your warranty. Major repairs requiring the removal of the units endcap voids the warranty unless
completed by a Danfoss Global Service Partner.
General Instructions
Remove the unit
Prior to performing major repairs, remove the unit from the vehicle/machine. Chock the wheels on the
vehicle or lock the mechanism to inhibit movement. Be aware that hydraulic fluid may be under high
pressure and/or hot. Inspect the outside of the pump and fittings for damage. Cap hoses and plug ports
after removal to prevent contamination.
Keep it clean
Cleanliness is a primary means of assuring satisfactory pump life, on either new or repaired units. Clean
the outside of the pump thoroughly before disassembly. Take care to avoid contamination of the system
ports. Cleaning parts using a clean solvent wash and air drying is usually adequate.
As with any precision equipment, keep all parts free of foreign materials and chemicals. Protect all
exposed sealing surfaces and open cavities from damage and foreign material. If left unattended, cover
the pump with a protective layer of plastic.
Lubricate moving parts
During assembly, coat all moving parts with clean hydraulic fluid. This assures that these parts are
lubricated during start-up.
Replace all O-rings and gaskets
Danfoss recommends you replace all O-rings, seals, and gaskets during repair.Lightly lubricate all O-rings
with clean petroleum jelly prior to assembly. Grease must be soluable in hydraulic fluid.
Service Manual
DDC20 Axial Piston Pumps
Introduction
4 | ©Danfoss | August 2017 L1120413 | AX00000135en-US0302

Secure the unit
For major repair, place the unit in a stable position with the shaft pointing downward. It is necessary to
secure the pump while removing and torquing components and fasteners.
Safety Precautions
Always consider safety precautions before beginning a service procedure. Protect yourself and others
from injury. Take the following general precautions whenever servicing a hydraulic system.
Unintended machine movement
W
Warning
Unintended movement of the machine or mechanism may cause injury to the technician or bystanders.
To protect against unintended movement, secure the machine or disable/disconnect the mechanism
while servicing.
Flammable cleaning solvents
W
Warning
Some cleaning solvents are flammable. To avoid possible fire, do not use cleaning solvents in an area
where a source of ignition may be present.
Fluid under pressure
W
Warning
Escaping hydraulic fluid under pressure can have sufficient force to penetrate your skin causing serious
injury and/or infection. This fluid may also be hot enough to cause burns. Use caution when dealing with
hydraulic fluid under pressure. Relieve pressure in the system before removing hoses, fittings, gauges, or
components. Never use your hand or any other body part to check for leaks in a pressurized line. Seek
medical attention immediately if you are cut by hydraulic fluid.
Personal safety
W
Warning
Protect yourself from injury. Use proper safety equipment, including safety glasses, at all times.
Service Manual
DDC20 Axial Piston Pumps
Introduction
©Danfoss | August 2017 L1120413 | AX00000135en-US0302 | 5

Symbols used in Danfoss literature
WARNING may result in injury Tip, helpful suggestion
CAUTION may result in damage to product or
property Lubricate with hydraulic fluid
Reusable part Apply grease / petroleum jelly
Non-reusable part, use a new part Apply locking compound
Non-removable item Inspect for wear or damage
Option - either part may exist Clean area or part
Superseded - parts are not interchangeable Be careful not to scratch or damage
Measurement required Note correct orientation
Flatness specification Mark orientation for reinstallation
Parallelism specification Torque specification
External hex head Press in - press fit
Internal hex head Pull out with tool – press fit
Torx head Cover splines with installation sleeve
O-ring boss port Pressure measurement/gauge location or
specification
The symbols above appear in the illustrations and text of this manual. They are intended to communicate
helpful information at the point where it is most useful to the reader. In most instances, the appearance
of the symbol itself denotes its meaning. The legend above defines each symbol and explains its purpose.
Service Manual
DDC20 Axial Piston Pumps
Introduction
6 | ©Danfoss | August 2017 L1120413 | AX00000135en-US0302

Gauge Port Locations and Gauge Installation - with Aux Pad
The following drawing and table show the gauge port locations and gauge sizes needed.
System port A
P108 561E
System port B
O-ring plug 9/16-18UNF-2B
L3 Case Drain
O-ring Plug 3/4-16UNF-2B
M3 Charge gauge / E- Charge inlet
O-ring plug 9/16-18UNF-2B
MA system pressure gauge port
O-ring plug 9/16-18UNF-2B
MB system pressure gauge port
O-ring plug 9/16-18UNF-2B
L1 Case Drain
O-ring Plug 3/4-16UNF-2B
L2 Case Drain
O-ring Plug 3/4-16UNF-2B
DDC20 with Aux Pad
M3 Charge gauge / E- Charge inlet
Port Information
Port Identifier Port Size Wrench Size Pressure Obtained Gauge Size, bar [psi]
L1/L2/L3 3/4-16 UNF 5/16 inch internal hex Case Drain 10 [100]
MA/MB 9/16-18 UNF 11/16 hex wrench System Pressure 500 [5000]
M3/E 9/16-18 UNF 1/4 inch internal hex Charge Pressure 50 [1000]
Service Manual
DDC20 Axial Piston Pumps
Pressure Measurements
©Danfoss | August 2017 L1120413 | AX00000135en-US0302 | 7

Gauge Port Locations and Gauge Installation - with Geroter
The following drawing and table show the gauge port locations and gauge sizes needed.
P109593
S-Charge
suction port
MA system pressure gage port
O-ring plug 9/16-18UNF-2B
L3 Case Drain
O-ring Plug 3/4-16UNF-2B
M3 Charge Pressure Gauge Port
O-ring Plug 7/16-20UNF-2B
DDC20 with Gerotor
L1 Case Drain
O-ring Plug 3/4-16UNF-2B
MB system pressure gage port
O-ring plug 9/16-18UNF-2B
Port Information
Port Identifier Port Size Wrench Size Pressure Obtained Gauge Size, bar [psi]
L1/L2/L3 3/4-16 UNF 5/16 inch internal hex Case Drain 10 [100]
MA/MB 9/16-18 UNF 11/16 hex wrench System Pressure 500 [5000]
S 7/8-14 UNF N/A (plastic shipping plug) Charge Inlet 2 [30] Vacuum
M3 7/16-20 UNF 3/16 inch internal hex Charge Pressure 50 [1000]
Service Manual
DDC20 Axial Piston Pumps
Pressure Measurements
8 | ©Danfoss | August 2017 L1120413 | AX00000135en-US0302

Gauge Port Locations and Gauge Installation - with Implement Pump
The following drawing and table show the gauge port locations and gauge sizes needed.
P108801
S-Charge
suction port
M3 Charge Pressure Gauge Port
O-ring Plug 9/16-18UNF-2B
DDC20 with Implement PumpL3 Case Drain
O-ring Plug 3/4-16UNF-2B
L1 Case Drain
O-ring Plug 3/4-16UNF-2B
MA system pressure gage port
O-ring plug 9/16-18UNF-2B
MB system pressure gage port
O-ring plug 9/16-18UNF-2B
ASystem Port
BSystem Port
L2 Case Drain Port
O-ring plug 3/4-16UNF-2B DImplement Discharge
O-ring plug 9/16-18UNF-2B
M3 Charge Gauge/
O-ring plug 9/16-18UNF
EImplement Return EImplement Return
Port Information
Port Identifier Port Size Wrench Size Pressure Obtained Gauge Size, bar [psi]
L1/L2/L3 3/4-16 UNF 5/16 inch internal hex Case Drain 10 [100]
MA/MB 9/16-18 UNF 11/16 hex wrench System Pressure 500 [5000]
S 7/8-14 UNF N/A (plastic shipping plug) Charge Inlet 2 [30] Vacuum
D 9/16-18 UNF 1/4 inch internal hex Implement Pressure 100 [2000]
M3/E 9/16-18 UNF 1/4 inch internal hex Charge Pressure 50 [1000]
Service Manual
DDC20 Axial Piston Pumps
Pressure Measurements
©Danfoss | August 2017 L1120413 | AX00000135en-US0302 | 9

Pump Adjustment
This section offers instruction on adjustment of pump components. Read through the entire topic before
beginning a service activity. Refer to Pressure Measurements on page 7 for location of gauge ports and
suggested gauge size.
Standard Procedures
C
Caution
Contamination can damage internal components and void the manufacturer’s warranty. Take
precautions to ensure system cleanliness when removing and reinstalling system lines
1. With the prime mover off, thoroughly clean the outside of the pump.
2. If removing the pump from the machine, tag each hydraulic line connected to the pump. If hydraulic
lines are disconnected, plug each open port, to ensure that dirt and contamination do not get into
the pump.
3. Ensure the surrounding areas of the machine are clean and free of contaminants such as dirt and
grime.
4. Look at the hydraulic fluid for signs of system contamination, oil discoloration, foam in the oil, sludge,
or small metal particles.
5. If there are signs of contamination in the hydraulic fluid, drain the hydraulic system, replace all filters,
flush the lines and fill the system with the proper hydraulic fluid.
Charge Pressure Relief Valve
The following procedure explains how to check for proper operation of the charge pressure relief valve.
Charge pressure is the measured pressure minus case drain pressure.
1. Install a 50 bar [1000 psi] pressure gauge at the charge pressure gauge port. Install a 10 bar [100 psi]
gauge at one of the case pressure ports. Operate the system with the pump in neutral (zero
displacement) when measuring charge pressure.
Pressure listed in model code assumes a charge flow of 15 l/min [4 US gal/min], and are referenced to
case pressure. At higher charge flows, the charge pressure will rise over the rated setting.
2. The table shows the acceptable pump charge pressure range for some nominal charge relief valve
settings (refer to model code located on serial number plate).
3. If measured pressure is not correct, disassemble the valve and look for signs of wear or
contamination. Refer to Torque charts on page 27 section for wrench sizes and torque settings.
4. If the valve is worn, replace the entire valve assembly.
5. Re-check the charge pressure setting.
Service Manual
DDC20 Axial Piston Pumps
Adjustments
10 | ©Danfoss | August 2017 L1120413 | AX00000135en-US0302

6. When the desired charge pressure setting is achieved, remove the gauges.
Charge pressure relief valve
P109626
J320
L200
L100
QJ040
Charge pressure
Model code Actual charge pressure
07 7 bar ± 1 bar
18 18 bar ± 1.5 bar
* This is the actual charge pressure port gauge reading minus the case pressure port gauge reading.
Factory set at 1800 min-1 (rpm) with a reservoir temperature of 50° C [120° F].
High Pressure Relief Valve - HPRV
The HPRV valves are pre-set at the factory. No adjustment is possible.
If you suspect a HPRV valve malfunction, replace valve with identical relief setting and test operation of
pump. Refer to Minor Repair on page 15 for replacement procedures.
Whenever you replace or open an HPRV, check for proper pump operation by cycling through its full
operating range.
Service Manual
DDC20 Axial Piston Pumps
Adjustments
©Danfoss | August 2017 L1120413 | AX00000135en-US0302 | 11

HPRV valves
P109625
QJ020
J140
QJ020
J150 P100
P110
N100
N110
Loop Flushing Valve
The loop flushing valve is not adjustable. If you suspect a loop flushing malfunction, disassemble the
valve and check for worn, damaged or scored components. Replace parts if necessary. Refer to Minor
Repair on page 15 for disassembly procedures.
Loop flushing valve
P108 569E
J220
H150
H200
H100
H200
H150
J230
Service Manual
DDC20 Axial Piston Pumps
Adjustments
12 | ©Danfoss | August 2017 L1120413 | AX00000135en-US0302

Overview
This section provides general steps to follow if you observe undesirable system conditions. Follow these
steps until you solve the problem. Some of the items are system specific. For areas this manual covers, we
reference the section. Always observe the safety precautions listed in Introduction on page 4, and
precautions related to your specific equipment.
System operating hot
Item Description Action
Oil level in reservoir. Insufficient hydraulic fluid will not meet cooling demands
of system.
Fill reservoir to proper level.
Heat exchanger. Heat exchanger not sufficiently cooling the system. Check air flow and input air temperature for heat
exchanger. Clean, repair or replace heat exchanger.
Charge pressure. Low charge pressure will overwork system. Measure charge pressure. Inspect and/or replace charge
relief valve. Inspect charge pump. Repair or replace charge
pump.
Charge pump inlet vacuum. High inlet vacuum will overwork system. A dirty filter will
increase the inlet vacuum. Inadequate line size will restrict
flow.
Check charge inlet vacuum. If high, inspect inlet filter and
replace as necessary. Check for adequate line size, length or
other restrictions
System relief pressure
settings.
If the system relief valves are worn, contaminated, or valve
settings are too low, the relief valves will be overworked.
Verify settings of high pressure relief valves and replace
valves as necessary.
System pressure. Frequent or long term operation over system relief setting
will create heat in system
Measure system pressure. If pressure is too high, reduce
loads.
Transmission operates normally in one direction only
Item Description Action
Control linkage Control linkage operating improperly Repair/replace control linkage
High pressure relief valve Malfunctioning HPRV can affect one direction while the
other functions normally.
Exchange the high pressure relief valves. If the problem
changes direction, replace the valve that does not operate
correctly. Settings may be different for forward/reverse.
System noise or vibration
Item Description Action
Oil level in reservoir Low oil level leads to cavitation. Fill reservoir.
Aeration of the oil/pump
inlet vacuum
Air in system decreases efficiency of units and controls. Air
in system is indicated by excessive noise in pump, foaming
in oil, and hot oil.
Find location where air is entering into the system and fix.
Check that inlet line is not restricted and is proper size.
Cold oil If oil is cold, it may be too viscous for proper function and
cause cavitation
Allow the oil to warm up to its normal operating
temperature with engine at idle speed.
Pump inlet vacuum High inlet vacuum causes noise/cavitation. Check that inlet line is not restricted and is proper size.
Check filter and bypass valves (if present).
Shaft couplings A loose shaft coupling will cause excessive noise. Replace loose shaft coupling.
Shaft alignment Misaligned shafts creates noise Align shafts.
Charge/High pressure relief
valves
Unusual noise may indicate sticking valves. Possible
contamination.
Clean/replace valves and test pump. May be a normal
condition.
Service Manual
DDC20 Axial Piston Pumps
Troubleshooting
©Danfoss | August 2017 L1120413 | AX00000135en-US0302 | 13

System will not operate in either direction
Item Description Action
Oil level in reservoir Low oil level leads to cavitation. Fill reservoir.
Open bypass valve If bypass valve is open, the system loop will be
depressurized.
Close bypass valve.
Low charge pressure with
pump in neutral
Low charge pressure insufficient to recharge system loop Measure charge pressure with the pump in neutral. If
pressure is low, go to Pump charge relief valve
Low charge pressure with
pump in stroke
Low charge pressure resulting from elevated loop leakage. Isolate pump from motor by blocking system ports. With
pump in partial stroke and engaged for only a few seconds,
check pump charge pressure. Low charge pressure
indicates a malfunctioning pump. Continue to next step.
Good charge pressure indicates a malfunctioning motor or
other system component. Check motor charge relief
operation (if present).
Pump charge relief valve. A pump charge relief valve that is leaky, or contaminated,
or set too low will depressurize the system.
Replace pump charge relief valve as necessary
Charge pump inlet filter. A clogged filter will under supply system loop. Inspect filter and replace if necessary.
Charge pump. A malfunctioning charge pump will provide insufficient
charge flow.
Repair or replace the charge pump.
System pressure Low system pressure does not provide enough power to
move load
Measure system pressure. Continue to next step.
High pressure relief valves Defective high pressure relief valves cause system pressure
to be low
Replace high pressure relief valves.
Control Linkage Linkage operating improperly Repair/replace control linkage
Sluggish system response
Item Description Action
Oil level in reservoir Low oil level causes sluggish response Fill reservoir
High pressure relief valves Incorrect system pressures will affect system reaction time.
High pressure relief valve with orifice may affect system
reaction time.
Replace high pressure relief valves
Low prime mover speed Low engine speed will reduce system performance Adjust engine speed
Air in system Air in system will produce sluggish system response Fill tank to proper level. Cycle system slowly for several
minutes to remove air from system
Pump inlet vacuum Inlet vacuum is too high resulting in reduced system
pressure.
Measure charge inlet vacuum. Inspect line for proper sizing.
Replace filter. Confirm proper bypass operation.
Bypass valve Slightly activated bypass valve will cause cross port
leakage.
Verify that the bypass valve is closed and that the valve is
seating properly. Clean, repair, or replace it as necessary.
Service Manual
DDC20 Axial Piston Pumps
Troubleshooting
14 | ©Danfoss | August 2017 L1120413 | AX00000135en-US0302

Charge Pump
Disassembly
1. Position the pump with the shaft end pointing down.
2. Mark the orientation of the charge pump cover on the endcap for proper reassembly.
3. Remove cap screws (K200). Remove the charge pump cover (K150).
4. Remove and discard O-ring (K100).
5. Remove gerotor (K010). Push out the drive pin (K050).
Inspection
Inspect all machined surfaces for wear or damage. If any nicks, scratches or wear are found replace
the cover and/or gerotor.
Assembly
1. Install drive pin (K050) into the shaft.
2. Lubricate and install the gerotor.
3. Lubricate and install O-ring into cover (K105).
4. Install the cover in its original position.
5. Install screws (K200). Torque screws per table.
Charge pump
P109623
K200
K100
K010
K050
K150
Service Manual
DDC20 Axial Piston Pumps
Minor Repair
©Danfoss | August 2017 L1120413 | AX00000135en-US0302 | 15

Item Wrench size Torque
K200 6 mm internal hex 20 N•m [15 lbf•ft]
Charge pump cover orientation
P109624
Flat
side
Counterclockwise rotation
Flat
side
Clockwise rotation
Service Manual
DDC20 Axial Piston Pumps
Minor Repair
16 | ©Danfoss | August 2017 L1120413 | AX00000135en-US0302

Implement Pump
Removal
1. Position the pump with the shaft end pointing down.
2. Remove cap screws (K200/K210). Remove the implement pump housing (K150).
3. Remove and discard O-ring (K100/K110).
4. Remove gerotor (K010). Remove locating pins (K250) from housing.
Implement Pump
P108802
K210 K200
K250
K100
K110
K010
Legened
Item Description Wrench size Torque
K200 Cap screw 8 mm internal hex 60 N･m [44 lbf･ft]
K210 Cap screw 8 mm internal hex 39 N･m [29 lbf･ft]
Service Manual
DDC20 Axial Piston Pumps
Minor Repair
©Danfoss | August 2017 L1120413 | AX00000135en-US0302 | 17

Inspection
Inspect all machined surfaces for wear or damage. If any nicks, scratches or wear and found replace
the housing and/or gerotor.
Assembly
1. Install locating pins (K250) into the endcap.
2. Lubricate and install gerotor (K010).
3. Lubricate and install O-ring (K100/K110) into housing (K150).
4. Install housing.
5. Install screws (K200/K210). Torque screws per table.
Shaft and Seal
Shaft seal removal
1. Orient pump with the shaft pointing up.
2. Using a retaining ring pliers, remove retaining ring (F125) .
3. Remove the shaft seal (F120) and discard.
C
Caution
Do not damage the housing bore, shaft or bearing when removing the shaft and shaft seal.
Carefully drive a small sheet-metal screw into the shaft seal to facilitate removal. Be careful not to
damage the bearing below the seal. Attach a slide hammer or appropriate puller to the screw head
and pull to remove the seal.
Service Manual
DDC20 Axial Piston Pumps
Minor Repair
18 | ©Danfoss | August 2017 L1120413 | AX00000135en-US0302

Seal, Shaft, Bearing
P108 526E
F125
F115
F120
F110
F105
F100
Service Manual
DDC20 Axial Piston Pumps
Minor Repair
©Danfoss | August 2017 L1120413 | AX00000135en-US0302 | 19

Shaft removal
1. Using a retaining ring pliers, remove retaining ring (F115).
2. Pull the shaft (F100), with bearing (F105), out of the pump. If necessary, tap lightly on the shaft to
dislodge it from the internal pump components.
C
Caution
Moving the pump with the shaft removed may dislodge the rotating group making reassembly
impossible without removing the endcap.
3. If replacing the bearing (F105), remove retaining ring (F110) using a retaining ring pliers.
4. Press on the inner race to remove the bearing (F105) from the shaft.
Shaft inspection
Ensure the shaft and its splines are straight and free of damage or heavy wear. Inspect the shaft
surface where it meets the shaft seal. Replace the shaft if a groove exists at the sealing land surface
that may let dirt into or hydraulic fluid out of the unit. Clean the sealing area with a nonabrasive
material if necessary. Lubricate the shaft with a light coat of hydraulic fluid before assembly.
Bearing inspection
Clean bearing with a solvent and lubricate with hydraulic fluid. Inspect for wear, or pitting. The
bearing should rotate smoothly. Replace the bearing if you feel any roughness.
Assembly
1. Position the pump with the shaft end pointing up.
If previously removed; press bearing onto shaft by applying force to the inner race.
2. Lubricate and install bearing (F105) with hydraulic fluid.
3. Install retaining ring (F110) using retaining ring pliers.
4. Install shaft (F100) with bearing (F105) into housing. Ensure the shaft splines engage the block splines
and the shaft end slides smoothly into the rear bearing. It may be necessary to tap lightly on the shaft
to seat the bearing.
5. Using retaining ring pliers, install the retaining ring (F115).
6. Cover shaft splines with an installation sleeve or packaging tape to protect seal during installation.
Lubricate new shaft seal (F120), press into housing until it bottoms out. Press evenly to avoid binding
and damaging the seal.
C
Caution
Do not damage the housing bore, shaft or rear bearing when installing the shaft and shaft seal. All
components should fit together smoothly.
Service Manual
DDC20 Axial Piston Pumps
Minor Repair
20 | ©Danfoss | August 2017 L1120413 | AX00000135en-US0302