Part of the Kubota Parts Manuals.
This is the factory Kubota LA403 Parts Catalog, a 36-page PDF you can download and print. It covers the LA403 front loader that mounts on Kubota compact tractors, listing every serviceable part across the loader's main frame, side frame, boom, control valve, control lever, and hydraulic system. Each section pairs an exploded diagram with a numbered parts list, so you can match a component to its exact Kubota part number, quantity, and serial-number range before you order.Use it to identify replacement hoses, tubes, cylinders, seal kits, couplers, and mounting hardware, or to rebuild the control valve and the boom and bucket cylinders. The catalog also flags country-specific and serial-break variations, which matters when one reference number carries more than one part number. Whether you are chasing a leak, rebuilding a cylinder, or ordering wear parts, this manual gives you the numbers you need.
What's Inside This Kubota LA403 Parts Manual
| System | Pages | Key Topics |
|---|---|---|
| Main Frame | 4-5 | Label Danger French, Label Caution French, Bolt, Washer |
| Side Frame | 6-7 | Label Danger French, Label Warning French, Label Lubricate English, Label Lubricate Fren French |
| Boom | 8-9 | Fitting Grease, Label Kubota, Label Leveler, Label Leveler French French, Fitting Grease -28T.T |
| Control Valve | 10-11 | Assy Adapter, Assy Elbow Adjustabl, Throttle, Nipple |
| Control Valve [R/V] | 12-13 | - |
| Control Valve [Component Parts] | 14-15 | O Ring, Ring Back Up, Seat Relief Valve, Spring Relief |
| Control Lever | 16-17 | Bush, Joint Rod End, Grip Lever, Bolt |
| Control Lever [R/V] | 18-20 | Assy Cable, Cable 1250MM, Rubber Bellows, Bolt |
| Cylinder/Hydraulic Hose | 21-22 | Cylinder 1, Cylinder 2, Hose 8 Hydraulic, Hose 9 Hydraulic, Band Code |
| Hydraulic Hose(Hyd.Outlet Block) | 23-24 | Hose 1 Hydraulic, Hose 2 Hydraulic, Coupler, Plug Dust, Sleeve |
| Hydraulic Tube | 25-26 | Tube 1 Hydraulic, Tube 2 Hydraulic, Tube 3 Hydraulic, Tube 4 Hydraulic, Cover Clamp, Clamp 3 |
| Cylinder (Boom)[Component Parts] | 27-28 | Tube 1 Comp., Rod 1 Comp., Head 1, Piston 1, Kit 1 Seal |
| Cylinder (Bucket)[Component Parts] | 29-30 | Tube 2 Comp., Rod 2 Comp., Head 2, Piston 2, Kit 2 Seal |
| Hydraulic Block | 31-34 | Elbow, Adapter, Band Code, Block Hydraulic, O Ring, Sleeve |
| Accessories and Service Parts | 35-36 | Operator'S Manual, Operators Manual Fr, Manual Supplement |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Nut thread size | 5/16-24UNF | p. 17 |
| HEX.Bolt thread size | M6*1.00*55 | p. 17 |
| Shim thickness | 0.1mm | p. 15 |
| Cable length | 1250mm | p. 20 |
| Fitting Grease thread size | 1/4-28T.T. | p. 9 |
Kubota LA403 Common Problems This Manual Covers
Loader will not lift or raises slowly
A loader that will not raise or moves very slowly usually points to the control valve, a clogged circuit, or air in the system. Use the exploded diagram and part numbers here to identify the valve assembly and its adapters and O-rings.
Manual Section: Control Valve p. 10Weak or jerky movement under load
Contaminated oil, internal leaks, or worn cylinder components can make the loader feel weak or inconsistent under load. This section lists the boom and bucket cylinder parts and seal kits needed for a rebuild.
Manual Section: Cylinder (Boom)[Component Parts] p. 27Bucket or boom ignores joystick input
When the loader does not follow joystick input, the fault often sits in the control lever, its linkage, or a mis-routed hose. The parts list identifies the lever, bushings, lock, and rod-end joints.
Manual Section: Control Lever p. 16Hydraulic leak at hoses or couplers
Seepage at hose ends and quick couplers is common with age and loader arm movement. This section covers the outlet-block hoses, coupler, dust plug, and sleeve so you can order exact replacements.
Manual Section: Hydraulic Hose(Hyd.Outlet Block) p. 23Worn detent or relief in the valve
Sticking detents or a tired relief valve cause erratic control and pressure loss. The component-parts breakdown lists the detent plug kit, relief valve kit, dust seal, and back-up rings.
Manual Section: Control Valve [Component Parts] p. 14Loader shifts or mounts feel loose
Loose mounting hardware lets the loader move on the tractor and stresses the frame. The main frame parts list gives the bolts, spring washers, and plain washers with the quantities used.
Manual Section: Main Frame p. 4Frequently Asked Questions
Which loader does this catalog cover?
It covers the Kubota LA403 front loader that mounts on Kubota compact tractors. It is a parts catalog, so it identifies components and Kubota part numbers rather than giving repair procedures or torque steps.
Can I find the exact control valve part numbers?
Yes. The Control Valve section shows an exploded diagram with the valve assembly, adapters, elbows, and O-rings, each tied to its Kubota part number and quantity for accurate ordering. p. 10
Does it list the parts to rebuild the boom and bucket cylinders?
It does. The cylinder component-parts sections break down the tube, rod, head, piston, and seal kit for both the boom and bucket cylinders so you can order rebuild parts. p. 27
How do I make sure a part fits my machine?
Each parts list carries a serial-number (S.No.) column and interchangeability notes, plus country-code remarks. Check your loader's serial number against the range shown before ordering, since some references list more than one part number.
What format is this manual in?
It is a 36-page searchable PDF that downloads instantly after checkout. Open it on a laptop, tablet, or phone and bring it straight to the shop floor.
Can I print this manual?
Yes. Print as many copies as you need, with no restrictions. Plenty of mechanics run off just the section they are working on and keep it at the bench.
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