Description

Daewoo D20S-3, D25S-3, D30S-3, GC20S-3, GC25S-3 1998 Repair Manual

You ever try to rebuild a steer axle with a third-party manual? I have. You end up chasing ghost torque specs and wondering why the kingpin won’t seat. That is why I only pull OEM when I have a Daewoo lift truck on my lift. This 1998 Daewoo D20S-3, D25S-3, D30S-3, GC20S-3, GC25S-3 1998 Repair Manual is the real deal — factory-issued, not a scanned copy from some guy’s basement. It covers disassembly and assembly of the whole vehicle systems index. If you are a shop owner or a home garage mechanic who works on these lift trucks, you need the actual specs, not a guess.

The Brake Valve Chapter: Factory Procedure for Lift Trucks

Page 54 in this manual covers the brake valve assembly. That is not a generic diagram. It is the OEM procedure for removing, inspecting, and reinstalling the brake valve on D20S-3 through GC25S-3 models. The manual lists required tools — no surprises. You will need a torque wrench that reads in inch-pounds for the valve body bolts because overtightening cracks the housing. I have seen that happen. This manual tells you the exact sequence and torque, not some footnote. If you skip the step that says to clean the O-ring groove with a non-abrasive pad, you will get a leak. The manual says it. Follow it.

Does This Manual Cover the Engine?

Yes. Chapter 79 deals with the engine. But understand this: the manual does not give you a rebuild guide for the entire internal combustion engine. It focuses on removal and installation of the engine assembly. If you need bottom-end bearing clearances, you want the Internal Combustion Engine service supplement. What this manual gives you is the lift-specific steps: how to disconnect the drive axle, unbolt the transmission, and lift the engine out without damaging the mast. There are torque values for the engine mounting bolts — and they are not the same as the generic engine specs. I have seen guys use standard automotive torque and snap the brackets. Page 79 has the correct numbers.

84 Pages of Vehicle Systems Disassembly

Eighty-four pages. Not 400. Not 20. The manual is lean because it only covers what you need for disassembly and assembly of the lift truck systems. You get sections on the mast (page 13), hydraulic control valves (page 66), primary lift cylinder (page 32), and steer axle (page 60). Each section is a complete procedure with part references and safety warnings. The safety section at the front is not boilerplate — it includes specific warnings about high-pressure hydraulic fluid and crushing hazards from the mast. I make every new tech read page 2 before they touch a Daewoo lift. They do not get to skip it.

Understand the Mast and Lift Cylinders Before You Start

If you are replacing the standard lift cylinders, the procedure is on page 26. The manual tells you to support the carriage with blocks — not a jack — because the cylinder weight shifts. It gives you the exact O-ring sizes for the hydraulic fittings. I have seen a mechanic use the wrong size O-ring and dump 30 gallons of oil on the shop floor. That is a $400 cleanup and a lost day. This manual gives you the part numbers, not a suggestion. The secondary lift cylinders are on page 29. Same level of detail: disassembly order, seal replacement, reassembly torque.

Hydraulic Control Valves: Factory Torque Specs

Page 66 breaks down the hydraulic control valves. There is a priority valve integrated with the pump (page 39). The manual shows the exploded view and the order of shims. If you change the valve spool without noting the shim stack, you will get erratic lift speed. I know because I had to redo a job where the tech ignored the manual. The torque for the valve body bolts is 30 ft-lbs. That is from Daewoo, not a guess. The Manual Transmission chapter (page 75) also includes drain plug torque — 35 ft-lbs. Do not overtighten the aluminum pan.

Related Manuals

• Daewoo Lift Trucks Specifications Systems Operation Testing & Adjusting
• Daewoo Lift Trucks Power Train Specifications Manual
• Daewoo D20S-3, D25S-3, D30S-3 2003 Service Manual – Factory Specs

FAQ

Does this manual include the steering unit rebuild procedure?

Yes. Steering unit is on page 44. It covers disassembly of the orbitrol and the check valves. You get the torque for the mounting bolts and the O-ring sizes. Do not lose the centering springs.

What is the publication year?

1998. Published by Daewoo, part number SB2105E00. It is the original factory manual, not a reprint.

Can I use this for GC30S-3 or G-series models?

The manual lists GC30S-3 and G20S-3 through G30S-3 in the header. However, the index only covers D20S-3 through GC25S-3 specifically. If you have a GC30S-3, check the steer axle section — it may apply, but the transmission ratios differ. You would be better off getting the exact model manual to avoid mismatched specs. The 84 pages are specific to the listed models.

Are the brake bleeding procedures included?

Yes. Page 54 includes the brake valve bleed sequence. It tells you to start at the wheel furthest from the master cylinder and work inward. The manual specifies the fluid type — DOT 4, not DOT 5. Do not mix them. Also gives the reservoir capacity in ounces.

Factory manual. Real specs. No guesswork. The D20S-3, D25S-3, D30S-3, GC20S-3, and GC25S-3 need this level of documentation if you want to avoid comebacks. I have been turning wrenches for 28 years, and I still check the manual every time I pull a steer axle or a lift cylinder. Access the Factory Manual now and keep it on your tablet or printed out. You will thank me when the brake valve bolts torque to spec the first time.