Doosan D512374 Lift Gp Secondary Cylinder STD | B15/18S5

Overview

The D512374 Lift Gp – Secondary Cylinder – STD is the standard-size secondary lift cylinder assembly for a family of Doosan electric forklifts. Mounted in the mast, it powers the second lifting stage and works hardest whenever the truck raises a full load to mid and upper heights. Over years of daily cycles, seals wear and rod surfaces take damage — symptoms that appear as mast drift, uneven fork heights, or slow lifting. Fitting the correct Doosan replacement restores original lifting speed and load-holding behavior. This STD (standard) version matches the original bore, stroke, and mounting dimensions, so it installs into the existing mast without modification.

Compatibility

The D512374 for B13/15/16R5(SB1088) covers several closely related Doosan electric model families:

• B13/15/16R5 series (SB1088)
• B15/18S5 series (SB1086)
• BC15/18S5 and BC20SC5 series (SB1087)
• BR10/13/14/15/18S2 series (SB1036)

These groups span compact counterbalance electrics and narrow-aisle warehouse trucks. Because mast configurations can vary within a series, always confirm the part number against your truck’s serial number or the Doosan parts manual before ordering. If you are unsure, send us your model and serial number and our team will verify fitment.

Quality and Reliability

This secondary cylinder group is built to the same dimensional and performance specifications Doosan applies to the original component. Matched bore, stroke, and rod diameter keep lifting force and speed consistent with factory behavior, while correctly positioned mounting points line up with existing brackets — no drilling or shimming required. The seal and wiper package is selected for hydraulic lift duty, helping the cylinder hold load position between overhauls. Choosing the exact D512374 rather than an improvised substitute protects the mast, chains, and hydraulic system from mismatched forces and premature wear.

Installation and Maintenance Tips

• Fully lower the forks, relieve hydraulic pressure, and support the mast and carriage before disconnecting any lines.
• Cap hoses and fittings immediately to keep contamination out of the hydraulic circuit.
• Compare the old cylinder with the new D512374 — check pin holes, hose routing, and stroke — before final assembly.
• Inspect lift chains, rollers, and the companion cylinder while the mast is open; worn parts on one side often explain uneven lifting.
• Torque mounts and fittings to the values in the Doosan service manual, bleed air from the circuit, and cycle the mast slowly through full travel under light load.
• Keep hydraulic oil clean and at the correct level; contamination is the most common cause of premature seal failure.

Why Order from Us

At ForkliftPartsSearch.com we list part numbers exactly as they appear in the original parts books, so searching D512374 brings you straight to this page. Our catalog covers Doosan electric counterbalance and warehouse trucks, and our support team can cross-check your model and serial number before you commit. Add the D512374 Lift Gp – Secondary Cylinder – STD to your cart today and get your mast lifting smoothly again.