Order the wrong valve part once and you've paid for the lesson. This Kubota BL4520 Parts Catalog exists to prevent that: 31 pages built around finding the correct part number before checkout. It carries exploded-view diagrams and numbered lists for 14 complete assemblies, from the main frame and boom through the swing, dipperstick, bucket, stabilizer, and boom cylinders. The valve assembly section splits individual seal kits down to the mylar shim, spool, spring retainer, and load check retainer, so you order the piece that actually failed rather than a kit you'll half-use. Replacement hoses spec at 9/16-18 x 1/4 NPT, and the main frame ball (Ref. No. 9) measures 1.5 inches, which keeps aftermarket cross-referencing quick. Search by part number or assembly name, then jump to the right diagram through the built-in bookmarks.
What's Inside This Kubota BL4520 Parts Manual
| System | Pages |
|---|---|
| Main Frame Assembly 4520 | 3-5 |
| Boom Assembly | 6-7 |
| Bucket & Dipstick Assembly | 8-9 |
| Hoses & Fittings | 10-11 |
| Tank & Pump Assembly | 12-13 |
| Gear Pump | 14-15 |
| Valve Control Linkage & Plumbing | 16-17 |
| Valve Assembly | 18-19 |
| Swing Cylinder | 20-21 |
| Dipperstick & Bucket Cylinder | 22-23 |
| Stabilizer Cylinder | 24-25 |
| Boom Cylinder | 26-27 |
| Mounting Kit L-4525 | 28-29 |
| Mounting Kit L-4522 | 30-31 |
Every system also includes seal kit.
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Capscrew Torque | 33-38 N-M/25-28 Ft. Lbs. | p. 14 |
| Hose Size (replacement) | 9/16-18 X 1/4 NPT | p. 11 |
| Fitting Size (replacement) | 9/16 FLARE X 1/2 X 1 | p. 13 |
| 8 CAPSCREWS Torque | 33 N-M | p. 14 |
| Ball ID (REF.No 9) | 1.5 inches | p. 4 |
| Pivot Pin Length (REF.No 12) | 5.875 inches | p. 4 |
| Cotter Pin Diameter (REF.No 36) | 0.09375 inches | p. 4 |
| Hex Bolt Thread Size (REF.No 39) | 1/4 NC X 3/4 | p. 4 |
| Clevis Pin Length (REF.No 41) | 1.875 inches | p. 4 |
| 12MM HEX NUT 1/25P Weight (REF.No 12, L-4525) | 0.01 kgf | p. 29 |
| 12MM X 1.25P X 30MM Bolt Weight (REF.No 13, L-4525) | 0.041 kgf | p. 29 |
| 14MM X 1/5P X 40MM Bolt Weight (REF.No 17, L-4525) | 0.069 kgf | p. 29 |
Kubota BL4520 Common Problems This Manual Covers
Kubota BL4520 control valve spool part number, one joystick section dead or intermittent p. 18
Check the Valve Assembly exploded view on page 18. The valve section lists individual part numbers for the Valve Body, Spool, Spring Retainer, Spring Shaft, and Spring Cap. Hose connections at the valve use 9/16-18 X 1/4 NPT fittings per page 11. Identify your section by position in the diagram, then pull the exact part numbers before ordering.
Manual Section: Valve AssemblyHydraulic hose blown or leaking at boom arm, need correct replacement part number p. 10
Open the Hoses & Fittings diagram on page 10. Locate the blown hose by position and reference number in the exploded view. Replacement hoses at this assembly spec 9/16-18 X 1/4 NPT per page 11. Record the reference number, pull the corresponding part number from the parts list, and verify it against your serial number range before ordering.
Manual Section: Hoses & FittingsTank or pump fittings weeping oil, need exact fitting part numbers to order p. 12
Pull the Tank & Pump Assembly diagram on page 12. Identify the leaking fitting by reference number in the exploded view. Fittings in this section are 9/16 FLARE X 1/2 X 1 per page 13. Match the reference number to the parts list for the exact part number, then verify the serial number range fits your machine.
Manual Section: Tank & Pump AssemblyGear pump replacement part numbers needed, also capscrew torque spec for reinstall p. 14
Start at the Gear Pump parts list on page 14. Locate each component by reference number in the exploded view and record its part number before ordering. Capscrews in this assembly torque to 33-38 N-M (25-28 ft. lbs.) per page 14. Confirm you have part numbers for every pump component before submitting the order.
Manual Section: Gear PumpBoom cylinder rod seal leaking, need seal and wiper ring part numbers p. 26
Turn to the Boom Cylinder section on page 26. Locate seal and wiper positions in the exploded view using reference numbers, then record the corresponding part numbers from the parts list. Cross-check the Hoses & Fittings section on page 10 if cylinder hoses also need replacement; hose connections at this assembly spec 9/16-18 X 1/4 NPT per page 11.
Manual Section: Boom CylinderMounting kit hardware list needed, unsure which mounting kit fits tractor model p. 28
Determine your mounting style before ordering: L-4525 parts begin on page 28, L-4522 on page 30. Each has its own exploded view and hardware parts list with distinct part numbers. The L-4525 kit includes a 14MM X 40MM capscrew at REF.No 17 per page 29. Match your tractor frame configuration to the correct section diagram before recording part numbers to order.
Manual Section: Mounting Kit L-4525Frequently Asked Questions
What are the torque specs for a Kubota BL4520?
The 8 capscrews in the GEAR PUMP assembly torque to 33-38 N-M (25-28 Ft. Lbs.). Hit that range on reassembly so the pump seats and seals correctly.
How to find torque specs for Kubota BL4520
Look in the GEAR PUMP section: the diagram prints the spec right on the page. The 8 capscrews torque to 33-38 N-M (25-28 Ft. Lbs.).
What are the replacement specifications for Hoses?
Hose replacements are listed by part number and dimension in the HOSES & FITTINGS section. Part No. 70020-01287 is a 9/16-18 X 1/4 NPT hose, and Part No. 70020-01206 is a 9/16 X9-1/16 hose.
What are the replacement specifications for Fittings?
Fittings appear in the same HOSES & FITTINGS section with part numbers and dimensions. For example, Part No. 70020-01287 is a 9/16-18 X 1/4 NPT fitting, and Part No. 70020-01209 is a 9/16 X 9/16 FLARE X fitting.
What do I get after purchasing this Kubota BL4520 manual?
A 31-page Parts Catalog in searchable PDF, ready the moment checkout completes. Read it on a computer, tablet, or phone, with no shipping wait.
Can I print specific sections of this Kubota BL4520 Parts Catalog?
Absolutely. No DRM or copy protection. Print the whole manual or just the pages you need. Any home or office printer works.
Document Quality
This document is a scanned PDF with an optical character recognition (OCR) layer, allowing you to search and copy text from the parts lists and instructions. The text throughout is crisp and easy to read, ensuring clarity for all information. Diagrams and illustrations are raster images, meaning they are clear and their labels are readable, though they may pixelate if zoomed in very closely. All pages are clean, free of any scan artifacts, stains, or marks, and are consistently straight. There are no notable blank or filler pages present in this document.
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