Description

Mitsubishi 4M40 1995 Technical Manual – Charging System Factory Specs

If you’re wrenching on a Mitsubishi 4M40 and the alternator is dead, you don’t want to spend two hours figuring out which bolt goes where only to find out you used the wrong torque and snapped a pivot bolt. I’ve pulled enough stripped threads out of engine blocks to tell you: factory specs are not optional. This Mitsubishi 4M40 1995 Technical Manual is exactly what the dealer technicians used. 26 pages of charging system information, no filler. Pull the alternator, check the brush length against the service limit (5 mm), measure rotor coil resistance, torque every bolt to the spec on page 16A-1-1. That’s how you do it right the first time.

Torque specs are on page 16A-1-1. You’ll see values for brace bolts, lock bolts, pivot bolts – all in Nm, kgm, and ft.lbs. If you use aftermarket numbers, you risk snapping bolts in the block. I’ve seen it happen.

26 Pages of OEM Charging System Specs

This manual covers the charging system exclusively. General information section shows exploded views of the alternator for petrol and diesel engines, including internal and external fan types. Service specifications list brush replacement limits – slip ring O.D. at 18.5 mm (0.728 in.) and brush length at 5 mm (0.20 in.). Rotor coil resistance for the 4M40 engine is 2.4–2.9 Ω for 65A, 2.3–2.7 Ω for 75A/90A. These are the numbers to use.

Torque Specifications for the 4M40 Engine

The torque table on page 16A-1-1 is specific. For the 4M40 engine: lock bolt 24 Nm (18 ft.lbs.), alternator pivot bolt nut 45 Nm (33 ft.lbs.). Brace bolt is 14 Nm (11 ft.lbs.). Alternator cover bolt M6 is 10 Nm (8 ft.lbs.), M8 is 13 Nm (10 ft.lbs.). Alternator bracket M8 is 23 Nm (17 ft.lbs.), M10 is 45 Nm (33 ft.lbs.). All that is on page 16A-1-1. If you’ve got a 6G72 or 6G74, the values differ – but for the 4M40 these are the numbers.

Alternator Removal and Installation: 4M40 Engine

Section 2 shows the removal steps for engines except 4G9, 6G72, etc. Then section 4 is dedicated to the 4M40 engine. Steps include brace bolt, spacer, pivot bolts, lock nut. The illustration on page 16A-2-1 shows the assembly. Note the torque callouts: 23 Nm (17 ft.lbs.), <4M40 engine> 45 Nm (33 ft.lbs.) for the pivot bolt nut. You need a 14 mm socket and a breaker bar. The diesel engine alternator comes with a vacuum pump mounted on the rear. The manual shows two types: internal fan and external fan. Both are covered. When reassembling, ensure the O-ring between pump and alternator is seated. Torque the mounting bolts properly – generic hand-tight will leak.

Disassembly and Reassembly – Factory Order

Page 16A-4-1 starts the disassembly procedure. You’ll separate the rear bracket, brush, electronic regulator, rectifier, rotor, stator, front bracket. The vacuum pump for diesel engines is on the rear. Brush replacement is critical – when it’s below the wear limit line, replace it. The manual gives the exact limit. For a deeper look at the entire engine, check the Mitsubishi 4M40 Engine Workshop Manual.

Why Factory Torque Data Matters

Aftermarket manuals often list generic values. This one has the factory specs. I’ve seen a lock bolt stripped because a tech used a generic 20 Nm instead of 24 Nm. That costs time and money. If you also work on other Mitsubishi models, the Mitsubishi Eclipse 1994 Technical Manual – Factory Specs & Torque Data covers the 4G63, and the Mitsubishi Galant Technical Manual – MPI 4G63 DOHC Factory Specs is useful for MPI systems. For a broader context on charging systems, see Automotive Industry Overview. For manual transmission related to this engine, refer to Manual Transmission.

Does this manual cover the fuel system?

No. This is strictly the charging system – alternator, regulator, and related wiring.

What about the diesel engine vacuum pump?

Yes. The manual includes illustrations for both internal and external fan type alternators used on the 4M40 diesel. The vacuum pump is mounted on the rear of the alternator. The removal and installation procedure covers the complete assembly, including the vacuum pump. Torque specs for the alternator pivot bolt nut on the 4M40 engine are 45 Nm (33 ft.lbs.). If you skip those specs, you risk belt misalignment and premature pump failure. Page 16A-4-1 shows the disassembly steps.

This is the real deal. Access the Factory Manual and get the specs Mitsubishi engineers intended.