Description

Bobcat 630, 631, 632 1987 Service Manual

If you own a Bobcat 630, 631, or 632 skid-steer loader from 1987, you already know that aftermarket manuals are a gamble. Wrong torque specs, missing sections, generic diagrams. This factory Service Manual is the original OEM document — 284 pages of the exact procedures the Melroe Company printed in 1987. No reprints, no third-party edits. This is the file that came off the press at the Bobcat factory.

Bobcat 630, 631, 632 1987 Service Manual: What’s in the Box

Page 1 opens with a safety warning that reads like a pre-flight checklist. Read it. The manual then breaks down into seven core sections: Preventive Maintenance, Engine Service, Hydraulic System, Hydrostatic System, Drive System, Main Frame, and Electrical. Each section is packed with step-by-step procedures, required tool lists, and OEM torque specifications. For example, the Fuel System section has separate procedures for the 630/632 and the 631, because those models use different pumps and carburetors. The manual even includes the serial number break points where design changes occurred — you need to know which range your machine falls into before you start.

Preventive Maintenance: Engine Oil and Filter

This section covers oil and filter changes, checking and adding oil, and the crankcase breather. The manual tells you exactly which filter part numbers to use and the correct oil capacity. It also includes the Bobcat Service Schedule — a table that tells you what to do at 30 hours, 250 hours, etc. If you ignore that schedule, you’re burning money on premature wear. The Engine service chapter details the air cleaner system and the cooling system for the 632. Page 1 reminds you to stop, cool, and clean the engine of flammable materials before checking fluids.

Fuel System Differences Between 630/632 and 631

The 630 and 632 share a common fuel system layout, while the 631 uses a different fuel pump and carburetor. This manual dedicates separate subsections to each. It walks you through fuel filter replacement, fuel pump checks, and carburetor adjustment — including the idle adjusting needle and throttle idle adjustment. If you have a 631, don’t use the instructions for the 630/632. The manual makes that clear.

Hydraulic System Troubleshooting: Where to Start

Now we get into the real meat. The hydraulic system section covers 37° flare connections, straight thread O-ring connections, and troubleshooting charts. It then goes into the control valve removal and disassembly, including detent spool repair and relief valve check. Want to check output of the hydraulic pump? That procedure is in here. The hydraulic cylinder repair section includes disassembly and assembly steps for both lift and tilt cylinders. If you’re dealing with a weak lift or drifting bucket, this is where you start.

Hydrostatic Motor Repair for Early and Late Serial Numbers

Bobcat changed the hydrostatic motors at specific serial number break points. The manual has separate repair sections for machines with serial numbers below 15376 (630) / 15321 (632) and above. It covers disassembly, inspection, and assembly of the hydrostatic pump and motors. It also includes the start-up procedure after repair, which is critical to avoid air locks or cavitation. Ignoring the serial number range will get you the wrong part numbers and wrong clearances.

3 Reasons to Use OEM Factory Specs

First, torque values. The manual gives you the exact ft-lbs for head bolts, hydraulic fittings, and drive chain adjustments. Aftermarket manuals often round off or guess. Second, wiring diagrams — the engine electrical system for 630, 631, and 632 is shown with factory pinouts. Third, safety warnings that are specific to this machine. Page 1 alone has warnings about hydraulic fluid injection, battery explosion, and lift arm support. You won’t find those in a generic manual.

Frequently Asked Questions

Does this manual cover the fuel system for all three models?

Yes, it includes separate sections for 630/632 and 631 fuel systems.

What torque specifications are provided?

The manual contains OEM torque specifications for critical fasteners such as cylinder head bolts, connecting rod nuts, hydraulic line fittings, and drive chain adjustments. These values are derived from factory testing and are not approximations. For example, the engine section provides torque for the head bolts, and the hydraulic section gives torque for 37° flare connections. Always refer to the manual for exact numbers before tightening. Using aftermarket specs on a machine this old can lead to stripped threads or catastrophic failure. I’ve seen it happen.

Does the manual include wiring diagrams?

The manual covers the engine electrical system including battery installation and ignition adjustments for 630 and 632. For wiring diagrams, look in the electrical section.

Can I use this manual for a Bobcat 631 with a different engine?

Yes, the manual has a dedicated section for the 631 fuel system, including the fuel pump and carburetor. The rest of the chassis, hydraulic, and hydrostatic systems are common.

Related Manuals:

• Bobcat S175 2008 Service Manual – OEM Factory Repair Specs
• Bobcat S185 2008 Service Manual – 998 Pages of Factory Specs
• Bobcat S70 2008 Service Manual – Factory Specs

The drive system section in this manual covers final drive and chain adjustments, but it does not cover a manual transmission — for that, see Manual Transmission on Wikipedia.

Similarly, Manual Transmission may be useful for understanding basic transmission concepts if you’re working on other equipment.

Stop guessing with worn-out aftermarket PDFs. This factory manual gives you the same information the dealer’s techs use. Get the job done right the first time. Access the Factory Manual now.