Pump service overview
This manual includes information on maintenance, troubleshooting, and minor repair of DDC20/24
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
.
For detailed technical information, refer to the
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
DDC20/24 Axial Piston Pumps
Introduction
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©
Danfoss | August 2019
L1120413 | AX00000135en-000401
