An hour from now you could have the front cover off a leaking wheel motor with this 72-page Poclain Hydraulics MK04, MKD04 repair manual PDF, factory document 800078102T covering both hydraulic motor variants. Troubleshooting trees walk from five symptoms (noisy motor, no rotation, low speed under load, rough running, external leaks) straight to the seal or valve at fault. Full teardown and rebuild sequences cover the brake piston seals, the distribution face and seals, the lip seal and protection plate, and a complete rotor plus stator inspection with wear assessment, backed by standard and special tooling lists. Before you refit the brake, confirm release pressure sits between 17 and 30 bar (246.6 to 435.1 PSI), then pull every fastener value from the torque summary table. Guess a brake pressure wrong and a loaded machine can roll. Bookmarked and text searchable, this PDF rides on whatever screen you carry out to the motor. Poclain published this one bilingually: the troubleshooting charts run French then English on facing pages, and the repair chapters carry both languages side by side, so every procedure, caption and torque figure is there in English.
What's Inside This Poclain Hydraulics MK04, MKD04 Repair Manual
| System | Pages | Key Topics |
|---|---|---|
| Trouble Shooting | 4-11 | The Motor Is Noisy, The Motor Does Not Revolve, The Motor Does Not Revolve at Its Normal Speed Under Load, The Motor Revolves Irregularly, The Motor Leaks |
| Basic Operations | 12-17 | Prerequisite (Related Documents, Component Identification), Safety and Quality (Before Servicing, During Servicing, After Servicing) |
| Mechanical Brake Release System (006) Replacement | 18-20 | Removing Plugs (191), Notched Rings (195), Screws (192) and Springs (193) From the Valving Cover, Refitting the Spacer Guides (196), Torquing the Plugs to Spec |
| Protective Plate (171), Lip Seal (172) and Sealing Ring (027) Replacement | 21-25 | Extracting the Lip Seal and Snap Ring (028), Checking the Seal Housings on Rotor (011) and Stator (026), Lubricating and Seating the New Sealing Ring, Refitting Thrust Washer (034) and Protective Plate |
| Sealing Unit (115)+(118)+(028) Replacement on the Hollow Shaft Motors | 26-30 | Removing Snap Rings (109) and (116), Extracting Tube (110), Replacing O-Ring (115), Sealing Ring (118) and Bushing (128), Checking the Mating Surfaces Before Reassembly |
| Brake Piston (107) Sealing (106)+(111) Replacement | 31-41 | Pressing the Valving Cover Off at 8800 N, Releasing the Mounting Screws in Diagonal Quarter Turns, Extracting the Brake Piston, Replacing O-Ring (106) and Sinus O-Ring (111), Brake Seal Pressure Test at 17 to 30 Bar |
| Valving (047) or Valving Seals (048) Replacement | 42-46 | Extracting the Timing Pin (050) and Springs (051), Replacing Back-Up Rings (048-1) and O-Rings (048-2), Heating the Back-Up Rings Before Fitting, Refitting the Valving Into the Cover |
| Rotor (011) and Stator (026) Assembly Inspection | 47-56 | Extracting the Balls (035) and Bearing Cage (036), Removing the Piston Assemblies (012), Visual and Nail Check of Piston Lapped Surfaces and Rollers, Rotor Bores, Stator Rolling and Bearing Track Surfaces, Brake Sealing Surfaces |
| Plug (114) Replacement | 57 | Stripping Down per the Brake Piston Sealing Chapter, Driving the Plug Out with a Bronze Casting Without Damaging the Rotor (011) Splines, Fitting the New Plug |
| Tooling Inventory | 58-62 | Commercial Tools, Specific Tools |
| Tightening Torques | 63 | Tightening Torques Summary, Standard Tightening Torques by Screw Class 8.8, And 12.9 |
| Spare Parts | 64-72 | Generic List of Item Numbers and Designations, Seal Kits (003, 006, 007, 061) and the Assemblies They Belong to |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| All Models | ||
| Brake release pressure | 17 to 30 bar [246.6 to 435.1 PSI] | p. 38 |
| Back-up ring (048-1) heating | 125°C [257°F] for 15 min in a furnace, or oil at 100°C [212°F] for 5 min | p. 44 |
| motors with the 10 bar brake release option | ||
| Brake release pressure, low-pressure release option | 10 bar | p. 34 |
| motors fitted with a snap ring | ||
| Valving cover (041) assembly press force | 8800 N [1978 lbf] | p. 39 |
| MK04, MKD04 | ||
| Brake mechanical release plug (191) torque, M16 | 60 ±6 N.m [44 ±4.4 lbf.ft] | p. 63 |
| Brake mechanical release CHC screw (192) torque, M8 | 30 ±3 N.m [22 ±2.2 lbf.ft] | p. 63 |
| Valving cover CHC screw (042) torque, M8 | 41 ±4 N.m [30 ±3 lbf.ft] | p. 63 |
Poclain Hydraulics MK04, MKD04 Common Problems This Manual Covers
Poclain Hydraulics MK04 wheel motor will not turn, pump running but machine drive is completely dead
Check pump flow and circuit pressure first, then confirm the brake is actually releasing. Tee a gauge into the brake release line; the piston needs 17 to 30 bar (246.6 to 435.1 PSI) to free the stack. Work the troubleshooting chart starting on page 4 before condemning the motor for internal seizure.
Manual Section: The motor does not revolve p. 4Machine will not freewheel for towing, parking brake drags and wheel motor runs hot
Test brake release pressure with a gauge teed into the release port; the piston needs 17 to 30 bar to pull the stack clear, per the spec on page 38. If pressure is good but the wheel still drags, replace the brake piston seals following page 31, and inspect the piston bore for scoring before reassembly.
Manual Section: Brake piston (107) sealing (106)+(111) replacement p. 38Motor loses speed and torque under load, runs sluggish and hydraulic oil overheats
Check pump flow and the replenishing circuit first, then measure case drain flow at the motor. Excess case flow points to internal leakage rather than a pump fault. Strip the motor and work the rotor and stator assembly inspection on page 47, which shows what scoring and wear on the functional surfaces look like and when the parts are past service.
Manual Section: Rotor (011) and stator (026) assembly inspection p. 47Oil leaking from motor shaft seal, film of hydraulic oil around hub and inner wheel
Clean the motor and pinpoint the source before ordering parts. Pressurize the brake release line to 17 to 30 bar and watch the brake piston area; if it stays dry, the lip seal is the leak path. Replace the protection plate, lip seal, and sealing ring following page 21, and check housing pressure and case drain routing first.
Manual Section: Protective plate (171), lip seal (172) and sealing ring (027) replacement p. 21Frequently Asked Questions
What are the torque specifications for the Poclain MK04 and MKD04 brake mechanical release plug?
The torque specification for the brake mechanical release plug (191) on both the MK04 and MKD04 motors is 60 ±6 N.m (44 ±4.4 lbf.ft). p. 63
What are the torque specifications for the Poclain MK04 and MKD04 cover mounting screws?
The torque specification for the cover mounting CHC screws (042) on both the MK04 and MKD04 motors is 41 ±4 N.m (30 ±3 lbf.ft). p. 63
What is the required force to apply on the valving cover during assembly?
When assembling the valving cover (041) for motors fitted with a snap ring, you must apply a force of 8800 N (1978 lbf) using a press and a mandrel. p. 39
What is the procedure for checking the brake piston sealing?
To check the brake piston sealing, apply a force of 8800 N (1978 lbf) on the piston, connect the X brake feed port to a hydraulic or compressed air source, and supply pressure between 17 and 30 bar (246.6 and 435.1 PSI). If the pressure remains stable, the seal is good. p. 38
What is the recommended temperature for heating the back-up rings during replacement?
When replacing the back-up rings (048-1), you must heat a furnace for 15 minutes at 125°C (257°F). Alternatively, you can heat the rings in oil at 100°C (212°F) for 5 minutes. p. 44
Do I get instant access to this Poclain Hydraulics MK04 Repair Manual?
You get a 72-page searchable PDF that downloads instantly after checkout. Open it on your laptop, tablet, or phone, and bring it right to the shop floor.
Can I print a copy of this Poclain Hydraulics MK04 Repair Manual for the shop?
You can. The PDF is unlocked and carries no copy protection, so print the sections you want and keep the file as your backup.
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