Doosan A138503 Booster (Shoe Type Brake) for D35/40/45S-2

Overview

The A138503 BOOSTER(SHOE TYPE BRAKE) is a replacement hydraulic brake booster for Doosan diesel forklifts in the 3.5-5.0 ton class. Working within the shoe type (drum) brake system, the booster amplifies the force applied to the brake pedal so the operator can achieve firm, consistent braking with minimal effort. When a booster begins to fail, symptoms often include a hard brake pedal, longer stopping distances, and uneven braking under load. Fitting a new A138503 for D35/40/45S-2 and the related SC-2 models restores dependable braking performance and helps keep your equipment safe and productive.

Compatibility

The Doosan A138503 brake booster is listed for the following forklift series:

• Doosan D35/40/45S-2 – 2-series diesel forklifts in the 35, 40, and 45 size classes
• Doosan D40/45/50SC-2 – 2-series SC configurations in the 40, 45, and 50 size classes

The part is also referenced with the application codes (A231526), (SB1077)(F.C.U), and (SB1053/DB58), covering the relevant build variants of these trucks, including units equipped with the DB58 engine. Because specifications can change within a series, always confirm your forklift’s model and serial number before ordering. If you are unsure whether the A138503 matches your machine, our team can help you verify the correct part.

Quality and Reliability

Brake components are safety-critical, and the A138503 BOOSTER(SHOE TYPE BRAKE) is supplied as a direct replacement for the factory-fitted Doosan booster. It is designed to match the mounting points, hydraulic connections, and operating characteristics of the original unit for the D35/40/45S-2 and D40/45/50SC-2 applications, so it installs in place of the old booster without modification. Sourcing the correct part number, rather than an approximation, protects braking performance, reduces downtime, and avoids the cost of repeat repairs.

Installation and Maintenance Tips

• Park the forklift on level ground, chock the wheels, and disconnect the battery before starting work.
• Relieve pressure in the brake circuit and disconnect hydraulic lines carefully; catch and dispose of old brake fluid properly.
• Compare the removed booster with the new A138503 to confirm bore size, mounting pattern, and connection points.
• Torque all mounting hardware to the values specified in the Doosan service manual.
• Bleed the brake system thoroughly after installation and inspect shoes, cylinders, and lines for wear or leaks.
• Test braking at low speed in a clear area before returning the forklift to full service.

Why Order from Us

At forkliftpartssearch.com, we specialize in Doosan forklift parts, including hard-to-find brake system components such as the A138503 BOOSTER(SHOE TYPE BRAKE). Our team checks part numbers against application data before dispatch, so you can order with confidence. Browse our catalog, request a quote for current pricing and availability, and get your D35/40/45S-2 or D40/45/50SC-2 back to work with the right part the first time.