Charge Check/Hprv; Removal; Inspection; Reassembly - Danfoss LDT 21 Service Manual

Service Manual
LDT 21/24/32 Closed Circuit Axial Piston Transmission
Minor Repair

Charge Check/HPRV

© Danfoss | June 2022
The high pressure relief and charge check valve assembly may be removed for cleaning and replacement
of the O-rings. These valves are factory set and are not field adjustable. Refer to the transmission model
code for the factory setting when ordering replacements.

Removal

1. Using an 24 mm hex wrench, remove the valve seat plugs (M300, N300).
2. Carefully lift the valve (M100, N100) and spring (M200, N200) assemblies from the center section
using a magnet.

Inspection

Inspect the valves and mating seats in the valve seat plugs for damage or foreign material.

Reassembly

1. Lubricate and install new O-rings (QM310, QN310) on valve seat plug (M300, N300).
2. Verify that the conical springs (M200, N200) are properly retained on the check relief valves (M100,
N100). Install the valve assemblies into the center section. Ensure each valve assembly moves freely in
its bore.
3. Install the valve seat plugs into the center section and torque to 78.4 N•m [58 lbf•ft].
4. Operate vehicle/machine through full range of controls to ensure proper operation. Check for leaks.
Charge Check/HPRV
Remove HPRV valves
N300
(*QN310)
N200
N100
( ) = not available individually
* = included in overhaul seal kit (see parts manuals)
M100
M200
(*QM310)
M300
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