Part of the Kubota Repair Manuals.
This Kubota Service Manual covers the angle dozer unit for the KX121-3 and KX161-3 excavators, publication number 97899-60550, in 24 pages. It is the factory workshop coverage for the KTC angle dozer blade, aimed at technicians servicing the blade and its hydraulics.Inside you get machine quality specifications, dozer lubrication points, dozer and angle lever force and stroke figures, and a full breakdown of the control valve, including relief pressure settings and fitting torque values. The rotary joint assembly, hose connections, undercarriage parts, and the complete hydraulic circuit with relief pressures for the travel motor, swivel motor, and pump are all documented.Use it when the dozer blade will not hold under load, the angle function drifts, or a fitting leaks after service. The manual downloads as a PDF and prints any page, so the pressure and torque numbers are on hand at the machine.
What's Inside This Kubota KX121-3, KX161-3 Manual
| System | Pages | Key Topics |
|---|---|---|
| Machine Quality Specifications | 4 | Main Specifications, Dimensions, Working Performance, Hydraulic Performance, Lever Operating Force & Stroke |
| Lubrication Point of Angle Dozer | 5 | Boom Bottom Linkage, Arm Bottom Linkage, Bucket Link Pin, Boom Cylinder Boss, Dozer Cylinder Boss, Angle Pin |
| Dozer Lever | 6-8 | Dozer Angle Operation, Angle |
| Control Valve | 9-14 | Specifications, General View of Control Valve, Control Valve Circuit Diagram, Angle Section, Adaptor Installation |
| Rotary Joint | 15-17 | Assembling of the Rotary Joint, Adaptor Installation, Hose Connection |
| Under Carriage | 18-20 | Angle Dozer, No. Part No. Part Name, View E, View D |
| Hydraulic Circuit | 21-24 | KX121-3 Hydraulic Circuit, Relief Pressure, Travel Motor, Swivel Motor, Pump |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| KX121-3 | ||
| Spool stroke (Mechanism operating section) | 7 mm 0.28 in | p. 9 |
| Spool stroke (Pilot operating section) | 7 mm 0.28 in | p. 9 |
| Tightening torque for fitting with 2-PF1/2 JIS O-PING TYPE (T2,T3) | 28.8~32.5 ft lbs | p. 11 |
| Tightening torque for fitting with 20-PF3/8 JIS O-RING TYPE (A1~A10,B1~B10) | 19.9~22.1 ft lbs | p. 11 |
| Hose, hydraulic (050) length | 460 mm | p. 17 |
| Hose, hydraulic (050) cap size | G1/4 - G1/4 | p. 17 |
| KX121-3 Angle blade type | ||
| Operating weight (Canopy) | 9080 lbs | p. 3 |
Kubota KX121-3, KX161-3 Common Problems This Manual Covers
Dozer blade will not hold under load
Blade circuit leakage, control valve wear, or a failed O-ring lets the dozer drop instead of holding the machine up. The control valve section covers the relief and overload pressure settings and valve construction.
Manual Section: Control Valve p. 9Blade or angle circuit drifts down
Leakage past the cylinder seals or valve spool lets the blade or angle function settle slowly. The hydraulic circuit section shows the relief pressures and flow paths for tracing the loss.
Manual Section: Hydraulic Circuit p. 21Leaks at hose or pipe connections
Improper torque, damaged threads, or an incorrect re-tightening sequence leaves fittings weeping after service. The rotary joint section details the hose connections and the correct assembly of the joint.
Manual Section: Rotary Joint p. 15Hydraulic trouble after service
Foreign matter entering during maintenance is the most common cause of hydraulic faults on these machines. The control valve section stresses cleanliness and gives the assembly and adaptor installation steps.
Manual Section: Control Valve p. 9Noise or stiffness at dozer pivots
Dry linkages and cylinder bosses create noise, vibration, and hard movement over time. The lubrication section identifies every grease point on the angle dozer that needs regular service.
Manual Section: Lubrication Point of Angle Dozer p. 5Dozer lever force or stroke off spec
A lever that feels heavy or has the wrong throw points to adjustment or wear in the linkage. The dozer lever section lists the correct operating force and stroke for the up, down, and angle functions.
Manual Section: Dozer Lever p. 6Frequently Asked Questions
Which machines does this manual cover?
It covers the angle dozer unit for the Kubota KX121-3 and KX161-3 excavators, the KTC optional blade attachment and its hydraulics.
What is the publication number?
This is Kubota service manual publication number 97899-60550, the angle dozer coverage from the KX121-3 and KX161-3 workshop manual.
What is the main relief pressure setting?
The main relief is set at 24.5 MPa, with the dozer overload relief at 11.8 MPa and the unload relief at 2.5 MPa. The control valve section covers the pressure settings. p. 9
What torque do the control valve fittings need?
The main relief valve fitting torques to 28.8 to 32.5 ft-lbs and the PF3/8 body ports to 19.9 to 22.1 ft-lbs. The control valve section lists each fitting value. p. 11
How quickly can I access this Kubota KX121-3 manual after buying?
A 24-page searchable PDF lands in your account the moment checkout clears. Open it on a laptop, tablet, or phone and take it straight to the shop floor.
Does this Kubota KX121-3 manual allow printing?
None at all. The PDF is DRM-free, so print whatever sections you want to carry out to the shop. Standard letter or A4 paper works fine.
Are hydraulic system diagrams in this Kubota KX121-3 Service Manual?
Included. Hydraulic system schematics cover all circuits, control valves, and component specifications for the Kubota KX121-3, KX161-3.
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