Description

Daimler Trucks North America CL112, CL120, STI-410, S21 2010 Workshop Manual

If you’ve ever tried to torque head bolts on a CL120 using a generic aftermarket manual that listed “tighten to spec” without giving you a sequence or a wet-vs-dry factor, you already know why I’m writing this. That frustration of pulling a transmission on a STI-410 and finding the wiring diagram on page 73 doesn’t match the harness in front of you — that’s the pain. I’ve been turning wrenches 28 years, and the difference between a job that goes smooth and one that costs you a weekend is the quality of the paper you’re referencing. This Daimler Trucks North America CL112, CL120, STI-410, S21 2010 Workshop Manual is the factory binder. Not a reprint, not a third-party compilation. Original OEM print from Daimler Trucks North America. 2385 pages of the same material the dealership techs use.

Every section — from the engine overhaul procedures to the ABS diagnostics — is written for a technician who expects exact fastener angles and fluid capacities. The manual covers four distinct chassis: CL112, CL120, STI-410, and S21. If you work on any of those, this is the only document you should trust.

CL112, CL120, STI-410, S21: What This Workshop Manual Covers

The table of contents breaks down into major system groups. Engine section (fc3100050wm) includes the full DD-series engine service — removal, disassembly, torque sequences for head bolts to the block. Transmission section (fc3201050wm) covers Manual Transmission and automated gearbox interfaces. You’ll find steering gear specs in fc3103050wm and brake system air plumbing in fc3106050wm. Each PDF file inside the bundle corresponds to a specific subsystem — no generic “engine” chapter that lumps everything together. The electrical section (fc4200050wm) gives you the wiring diagrams with connector pinouts.

Need the charge pressure? Page 73 for the fuel system table. Need the wheel bearing adjustment? Look in fc3108050wm under “Front Wheel Bearings.” The manual doesn’t waste space telling you what a wrench is — it assumes you have basic mechanical skill and need the factory number.

3 Drivetrain Sections You Should Bookmark

First, the clutch and driveline section (fc3202050wm). If you’re swapping a clutch on a S21, the manual gives you the release bearing clearance spec and the flywheel bolt torque in foot-pounds — not newton-meters converted wrong. Second, the rear axle section (fc3503050wm) covers the Meritor and Dana axles used on these trucks. Third, the frame section (fc1500050wm) includes the C-channel reinforcement callouts for the STI-410. Bookmark those three and you’ll cut down your search time.

Torque Specs: Why Aftermarket Manuals Get Them Wrong

I’ve seen aftermarket manuals list a main bearing cap bolt at 90 ft-lb when the factory calls for 90 ft-lb plus 90 degrees. That’s a broken block waiting to happen. This manual has the torque-angle table printed right in the engine section (fc3100110wm). Every fastener grade is specified — use the correct socket size or you’ll strip the hex. The manual also includes a warning about reusing TTY bolts. I’ve had apprentices ignore that and pay for it later. Don’t be that guy.

The brake section (fc3106050wm) lists the air compressor mounting bolt torque and the slack adjuster stroke check procedure. You want to get brake inspection right on a CL120? This is your insurance.

Does This Manual Cover the Engine Control Module?

Yes. The electrical and electronic section (fc4200050wm through fc4226120wm) covers the Detroit Diesel DDEC and the Cummins ISX ECM integration. You get pin-out diagrams, diagnostic trouble code tables, and the power-up sequence test. If you’re chasing a no-start on a STI-410, you can trace the ECM power supply back through the fuse box schematics. Works for the S21 models too — but check the supplement date. This manual includes Supplement 21, June 2010, which updates the wiring for later production trucks.

Get the Right Wiring Diagrams With Factory Schematics

Aftermarket diagrams often combine multiple harness options into one confusing mess. The Daimler manual gives you separate sheets for each configuration — standard, heavy-duty, and optional auxiliary. The legend (page 2 of the electrical section) explains the color codes and connector views. Use a highlighter to mark your truck’s options. I’ve used this manual to fix a trailer ABS fault on a CL112 by tracing the circuit to a bad splice behind the dash — took 20 minutes because the diagram was accurate.

If you also work on other Daimler platforms, check the related Sterling Bullet Owner’s Manual, the Daimler Trucks 2010 Service Manual: XCL-XCR-XCP-XCS-MC, and the Daimler Coronado Maintenance Manual Models 122 132. Each covers different chassis, but the torque philosophy is the same. And for clutch linkage specifics, refer to the Manual Transmission section in the drivetrain chapter.

How to Use This 2385-Page Manual Without Getting Lost

Split the PDFs by bookmark. The file names follow a pattern: fc + system code + sequence. Open fc1301050wm for cab body, fc2002050wm for exhaust, fc2501050wm for HVAC. The workshop manual is designed for a technician to jump to the system — not read cover to cover. Keep a notebook with your common sections. I’ve got the steering gear torque pages (fc3103110wm) bookmarked on my tablet.

One more thing: The manual says on page 3 that major component service info (engine, transmission, axle internals) is in the manufacturer’s separate manual. That’s correct. This workshop manual covers the vehicle integration — mounting brackets, air lines, wiring, cab removal, frame repairs. Don’t expect it to show you how to rebuild a transmission planetary; that’s the Manual Transmission manual. Use this for the truck itself.

Source Authenticity: OEM vs Aftermarket

I don’t trust aftermarket documentation on principle. I’ve seen too many torque values off by 15 ft-lb and wiring diagrams flipped left-to-right. This is a direct PDF copy of the Daimler Trucks North America binder. Published 2010, no guesswork. The copyright page (page 2) shows Daimler Trucks North America LLC, Portland, OR. Every section carries the official part number. If you need to cuss a technician for using the wrong spec, you can point to this manual and say “factory.”

Frequently Asked Questions

Does this manual cover the Detroit Diesel engine?

Yes. The engine section includes DD13, DD15, and DD16 service procedures.

Is the wiring diagram color-coded?

Yes, but you need to study the legend. The manual uses standard SAE color codes and identifies connector cavity numbers.

Can I use this manual for the S21 model?

The S21 is explicitly covered in this workshop manual. Section fc3100050wm includes the S21 chassis-specific frame rail dimensions and air system routing. Note that Supplement 21 (June 2010) contains updates for the S21 — always check that supplement if you’re working on a late-2010 build. The manual warns that some procedures changed after initial printing.

What torque wrench should I use for the head bolts?

A calibrated click-type wrench with an angle gauge. The manual specifies both ft-lb and degrees.

If you work on these Daimler trucks daily or even once a month, you need the factory data. Don’t waste time questioning a number that came from a third-party source. Access the Factory Manual now and keep it on your tablet or printed in a binder. Your next torque sequence will be right the first time.