Overview
This manual details major repair procedures for H1 pumps. These include the complete disassembly,
inspection, and reassembly of the unit. Where rework of worn or damaged components is possible,
specifications appear to ensure these parts meet factory tolerances. Only Danfoss Global Service Partners
(GSPs) are authorized to perform major repairs. Danfoss trains Global Service Partners and certifies their
facilities on a regular basis.
W
Warning
Use of components that do not comply with rework specifications may result in loss of performance,
which may constitute a safety hazard. Do not reuse components that don't comply to given
specifications: replace with genuine Danfoss service parts.
Minor repair procedures, adjustments, and troubleshooting information appear in the
H1 078/147/165
Closed Circuit Axial Piston Pumps Service Manual
, 520L0848. Minor repairs include service operations you
can perform without removing the unit's endcap. Removal of the endcap voids your warranty.
General Instructions
Follow these general procedures when repairing H1 variable displacement closed circuit pumps.
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.
Repair Instructions
H1 45/53/60/68 Closed Circuit Axial Piston Pumps
Introduction
520L0957 • Rev CB • September 2014
5
