In 1932, 1st B46 coach (the Fuso) was built within Mitsubishi Shipbuilding Company's Kobe Works. Couple of years later, the Mitsubishi Shipbuilding providers was rebranded Mitsubishi Heavy sectors (MHI). Three-years after that, the MHI motor-vehicle functions in the Kobe work were used in the Tokyo work.

In 1949, the Fuso engines marketing business ended up being founded; it absolutely was renamed the Mitsubishi Fuso engines Sales Company in 1952. In 1950, Mitsubishi significant Industries was divided into three businesses: East Japan significant companies, Central Japan significant companies and western Japan Heavy companies. Two years later on, Central Japan significant sectors ended up being rebranded Shin Mitsubishi Heavy sectors; West Japan Heavy sectors was rebranded Mitsubishi Shipbuilding and Engineering business and East Japan Heavy companies ended up being rebranded Mitsubishi Nippon significant Industries (MNHI). Merchandise through the companies had been distributed by Mitsubishi Fuso Motor product sales because of brand name recognition.

In 1957, MNHI incorporated the Tokyo and Kawasaki work in to the Tokyo Motor Vehicle Functions. Seven many years later on, Mitsubishi Nippon significant Industries, Shin Mitsubishi Heavy sectors and Mitsubishi Shipbuilding and Engineering business combined to form Mitsubishi Fuso Heavy Industries; Mitsubishi Fuso Motors deals put into two divisions: Shin and Fuso Motors business business. Revealing a logo, they separate the circulation of hefty and lighter machines; Shin distributed light machinery branded as Mitsubishi, and Fuso distributed heavier machinery branded as Fuso. In 1970 MHI finalized a joint-venture arrangement with Chrysler firm, establishing the Mitsubishi engines business (MMC), and MHI transported its motor-vehicle operations to MMC.

In 1975, MMC launched the Nakatsu Plant at their Tokyo Motor Vehicle Works; five years later, they started the Kitsuregawa Proving reasons. Four years after that, MMC combined with Mitsubishi Motor Sales providers. In 1985, MMC and Mitsubishi Corporation founded the joint-equity company Mitsubishi vehicles of The united states in the United States. Eight ages later, MMC and Chrysler mixed their particular equity partnership. Listed here year, MMC and Mitsubishi joined to design, build and circulate the Mitsubishi Lancer.

In 1999 MMC and Volvo accompanied their particular truck and coach procedures, and Volvo obtained five per cent of MMC. Two years later on, DaimlerChrysler replaced Volvo as MMC's vehicle and coach partner and MMC rebranded the Tokyo Plant the Truck and Bus manufacturing Office (also referred to as the Kawasaki Plant).

In 2003, the Mitsubishi Fuso Truck and coach firm (MFTBC) is founded. DaimlerChrysler, Mitsubishi engines business as well as other Mitsubishi companies acquired 43-, 42- and 15-percent stocks, correspondingly, in MFTBC. In 2005, Mitsubishi engines organization moved its MFTBC stocks to DaimlerChrysler as an element of their payment arrangement for economic problems caused by high quality problems and recalls at MFTBC. DaimlerChrylser while the Mitsubishi firms hold shares of 89 and 11 percent, correspondingly. In 2006, MFTBC moved its headquarters from Tokyo to Kawasaki-shi, Kanagawa; the following year, DaimlerChrysler marketed their bulk stake in Chrysler Corporation to Cerberus Capital administration. The corporation is rebranded Daimler AG, as well as the DaimlerChrysler vehicle team had been renamed Daimler Trucks; MFTBC is a component associated with the Daimler vehicles unit of Daimler AG.

The Diesel system (also referred to as a compression-ignition or CI engine), known as after Rudolf Diesel, is an inside combustion system by which ignition of this gas, that is inserted into the combustion chamber, was due to the higher temperatures of this environment in cylinder due to the technical compression (adiabatic compression). Diesel machines jobs by compressing just the atmosphere. This escalates the air temperatures in the cylinder to these types of a higher degree that atomised Diesel fuel inserted in to the combustion chamber ignites spontaneously. Using the gasoline becoming inserted into the environment prior to burning, the dispersion associated with the gas was unequal; this is called a heterogeneous air-fuel blend. The process of blending air and gasoline happens very nearly totally during combustion, the oxygen diffuses in to the flame, which means the Diesel motor operates with a diffusion fire. The torque a Diesel engine brings try monitored by manipulating air ratio; what this means is, that rather than throttling the intake environment, the Diesel system relies on altering the amount of fuel that's injected, plus the atmosphere ratio is normally higher.

The Diesel motor gets the highest thermal performance (engine performance) of any useful internal or external combustion motor due to its quite high expansion ratio and inherent lean burn which makes it possible for temperatures dissipation because of the excess atmosphere. A small efficiency reduction can also be avoided compared with two-stroke non-direct-injection gas machines since unburned fuel is not current at valve overlap therefore no gasoline goes straight through the intake/injection to your fatigue. Low-speed Diesel motors (as utilized in vessels alongside solutions where general engine weight was relatively unimportant) can get to efficient efficiencies of up to 55%.

Diesel engines is designed as either two-stroke or four-stroke cycles. They certainly were originally used as a far more efficient replacement for fixed steam motors. Since the 1910s they have been used in submarines and ships. Used in locomotives, vehicles, heavy products and electrical energy generation flowers used later. Inside 1930s, they gradually started initially to be properly used in a few vehicles. Because the 1970s, the application of Diesel motors in larger on-road and off road automobiles in america has increased. According to Konrad Reif, the EU average for Diesel vehicles makes up about 50percent associated with total newly signed up.

A four-stroke (furthermore four-cycle) engine was an interior combustion (IC) motor in which the piston completes four individual strokes while switching the crankshaft. A stroke is the full vacation of this piston over the cylinder, either in way. The four split shots become called:

Consumption: also referred to as induction or suction. This stroke of this piston begins at top dead-center (T.D.C.) and comes to an end at bottom dead-center (B.D.C.). In this stroke the intake valve must certanly be in the wild place whilst piston pulls an air-fuel combination in to the cylinder by producing vacuum stress in to the cylinder through their downward movement. The piston is moving straight down as atmosphere has been sucked in because of the downward motion against the piston.
Compression: This stroke begins at B.D.C, or simply just after the suction stroke, and ends up at T.D.C. In this swing the piston compresses the air-fuel combination in preparation for ignition during power stroke (below). Both consumption and fatigue valves become shut with this stage.
Burning: also referred to as power or ignition. This is actually the start of the 2nd revolution of four stroke cycle. At this time the crankshaft have finished a full 360 level change. Whilst the piston are at T.D.C. (the termination of the compression stroke) the compressed air-fuel mixture is ignited by a spark plug (in a gasoline motor) or by temperature generated by high-compression (diesel machines), forcefully going back the piston to B.D.C. This swing creates technical work through the system to turn the crankshaft.
Exhaust: Also known as outlet. During the exhaust swing, the piston, yet again, comes back from B.D.C. to T.D.C. whilst fatigue device was open. This course of action expels the devoted air-fuel combination through the exhaust valve.

When you look at the diesel engine, atmosphere are squeezed adiabatically with a compression ratio usually between 15 and 20. This compression increases the temperature towards the ignition temperatures of the gas combination which is formed by injecting gas once the atmosphere try compressed.

The perfect air-standard pattern try modeled as a reversible adiabatic compression accompanied by a constant force combustion processes, then an adiabatic growth as a power swing and an isovolumetric fatigue. An innovative new environment cost is taken in at the end of the fatigue, as indicated because of the procedures a-e-a on diagram.

A turbocharger, colloquially referred to as a turbo, was a turbine-driven forced induction unit that grows an internal burning system's effectiveness and energy production by forcing extra compressed-air to the burning chamber. This improvement over a normally aspirated engine's energy production is because of the fact the compressor can push considerably air---and proportionately much more fuel---into the burning chamber than atmospheric pressure (as well as for that material, ram air intakes) alone.

Turbochargers are initially known as turbosuperchargers whenever all pushed induction equipment had been classified as superchargers. Today the definition of "supercharger" is typically used only to mechanically driven pushed induction devices. The main element difference between a turbocharger and the standard supercharger is that a supercharger is mechanically driven because of the system, often through a belt attached to the crankshaft, whereas a turbocharger was running on a turbine driven because of the motor's fatigue gas. In contrast to a mechanically driven supercharger, turbochargers are more efficient, but less receptive. Twincharger identifies an engine with both a supercharger and a turbocharger.

Turbochargers are generally utilized on truck, car, train, plane, and building products motors. These are typically most often combined with Otto pattern and Diesel cycle internal combustion machines.

Contrary to turbochargers, superchargers is mechanically driven by the motor. Devices, chains, shafts, and gears are common ways of powering a supercharger, putting a mechanical burden from the system. Including, on the single-stage single-speed supercharged Rolls-Royce Merlin engine, the supercharger utilizes about 150 horse power (110 kilowatts). The importance exceed the costs; for the 150 hp (110 kW) to-drive the supercharger the engine produces another 400-horsepower, a net build of 250 hp (190 kW). This is where the main downside of a supercharger becomes evident; the engine must endure the web power output of the motor plus the power to drive the supercharger.

Another disadvantage of some superchargers is gloomier adiabatic efficiency in comparison with turbochargers (especially Roots-type superchargers). Adiabatic effectiveness are a measure of a compressor's power to compress environment without incorporating extra temperature to that particular environment. Even under perfect problems, the compression process always results in elevated output temperatures; but more cost-effective compressors create less excess temperatures. Origins superchargers provide significantly more temperature into atmosphere than turbochargers. Therefore, for certain volume and force of environment, the turbocharged atmosphere try cooler, and for that reason denser, containing additional oxygen molecules, and therefore more prospective energy compared to supercharged environment. In program the disparity amongst the two could be dramatic, with turbochargers often making 15percent to 30percent even more power based exclusively on the variations in adiabatic efficiency (however, as a result of warm transfer from the hot exhaust, considerable warming occurs).

In contrast, a turbocharger will not setting an immediate mechanical burden from the engine, although turbochargers setting exhaust back-pressure on machines, increasing pumping losings. This will be better because whilst the increased back pressure taxes the piston fatigue stroke, much of the power driving the turbine try given by the still-expanding exhaust gasoline that would usually become lost as temperatures through tailpipe. In comparison to supercharging, the primary drawback of turbocharging is exactly what is called "lag" or "spool time". It is now time between the demand for a rise in power (the throttle being opened) and also the turbocharger(s) providing increased intake force, and hence increased energy.

Throttle lag occurs because turbochargers count on the accumulation of exhaust gasoline pressure to-drive the turbine. In adjustable output systems such automobile engines, exhaust gasoline force at idle, low engine speeds, or reduced throttle is generally inadequate to-drive the turbine. Only if the motor achieves enough rate do the turbine section start to spool up, or twist quickly enough to produce intake force above atmospheric pressure.

A combination of an exhaust-driven turbocharger and an engine-driven supercharger can mitigate the weaknesses of both. This technique is called twincharging.

In the case of Electro-Motive Diesel's two-stroke machines, the mechanically assisted turbocharger just isn't specifically a twincharger, whilst the motor makes use of the technical assist with charge atmosphere best at lower engine speeds and startup. As soon as above notch # 5, the motor uses real turbocharging. This differs from a turbocharger that makes use of the compressor section of the turbo-compressor just during starting and, as a two-stroke motors cannot obviously aspirate, and, relating to SAE definitions, a two-stroke motor with a mechanically assisted compressor during idle and lowest throttle is considered naturally aspirated.

Mitsubishi Diesel Engine | eBay

This is the popular 4D34, 3.9 4 Cyl Diesel engine used in the Mitsubishi FUSO trucks from 1999-2004. It may fit other applications. This FE FUSO was wrecked in the Roof of the dry van body.

A List of all the Mitsubishi Engines on Diesel Engine Trader

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Mitsubishi Motors engines - Wikipedia

Mitsubishi Motors engines. Jump to navigation Jump to search. This is a list of engines produced by Mitsubishi Motors since 1964, and its predecessors prior to this. Explanation of codes. Mitsubishi engines designed since 1970 use a four-digit naming convention: The first ...

Home - Mitsubishi Heavy Industries - VST Diesel Engines ...

MITSUBISHI HEAVY INDUSTRIES-VST DIESEL ENGINES PRIVATE LTD (MVDE), a joint venture between Mitsubishi Heavy Industries Ltd, Japan & VST Tillers Tractors Ltd, India was established in 2007 at Mysore to manufacture Diesel Engines.

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Mitsubishi Diesel Engine Parts. Parts Supply Corporation supplies Mitsubishi Diesel Engine Parts, Engine Gasket Sets, Bearing Sets, ReRing Kits, and engine parts and spares.

Mitsubishi Diesel Engines - Stauffer Diesel

The engines are engineered for durability and distinguished by reliability. At Stauffer Diesel, we stock an inventory of Mitsubishi small diesel engines, and we have a full spectrum of support services available for these engines, including parts and service. Application engineering and build-to-spec services are also available. Features of the ...

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Mitsubishi Diesel Engine Spare Parts. Mitsubishi Heavy Industries Ltd. is a leading Japanese company that is famous worldwide for being one of the largest producers of power generation equipment, machine tools and aerospace components.

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Brief theory — why valve guides wear and why repair matters
- What a valve guide does: a valve guide is a hardened cylindrical sleeve pressed into the cylinder head that the valve stem slides inside. It keeps the valve aligned with the valve seat so the valve seals reliably, transfers heat from the valve into the head, and meters oil to the valve stem.
- Analogy: think of the valve as a door on a hinge and the valve guide as the hinge bush. If the hinge bushing wears, the door droops and rubs, leaks air, or wobbles and damages the frame.
- Why they wear: dirty oil, poor lubrication, high temperatures, abrasive particulates, or long service life. Worn guides allow excessive valve stem side-play.
- Symptoms of bad guides: blue/gray smoke at startup or under load (oil burning past worn guides), increased oil consumption, rough idle, loss of compression (if valve doesn’t seat perfectly), valve stem wobble visible when rocker/cam removed, rapid valve/seat wear.
- Consequences if ignored: poor sealing and power loss, burned valves, accelerated valve-seat wear, eventual valve sticking or seizure, head damage.

Overview of how the whole valve-train system ties together (so you understand where guides fit)
- Valve: the moving part that opens/closes the port. Stem (shaft) and head.
- Valve seat: hardened ring in the head the valve face seals against when closed.
- Valve guide: the sleeve that aligns the valve stem as it moves.
- Valve stem seal: rubber/metal seal that limits oil flow down the stem into the combustion chamber.
- Valve spring, retainer, keepers/collets: hold valve closed and return it after cam lift.
- Camshaft and cam lobes: push on lifters/rockers or buckets to open valves.
- Rocker arms/buckets/lifters: transmit cam motion to valves (arrangement varies by engine).
- Cylinder head: houses guides, seats, ports, cooling passages.
- Timing gear/chain/belt: synchronizes camshaft(s) and crankshaft.

Tools, materials and measurements you will need
- Factory service manual for Mitsubishi 4M50 — mandatory for torque specs, clearances, sequences, and OEM part numbers.
- Metric socket/ratchet set, torque wrench (capable of specified torques).
- Engine hoist or support if head removal requires lifting off a heavy assembly.
- Valve spring compressor (suitable for the head design).
- Press or arbor and suitable drivers for removing/pressing guides (hydraulic or arbor press recommended).
- Valve guide driver set sized for old/new guides.
- Precision measuring tools: micrometer (for valve stem diameter), inside micrometer or telescoping gauge + micrometer (for guide bore after reaming), dial indicator if checking runout.
- Reamer set (hand reamers or a machine reamer sized to new valve guide final ID).
- Valve lapping tools (stick and compound) or a seat-cutting setup if seats are worn.
- Cleaning tools (wire brushes, solvent, compressed air).
- New valve guides (OEM or equivalent), new valve stem seals, new head gasket, new head bolts if specified as torque-to-yield.
- Loctite or anti-seize where specified by manual.
- Soft-faced hammer, drift pins, punches.
- Heat source: oven or heat gun (or induction heater) to expand head, or freezer to shrink guides for press fit — follow recommended method.
- Torque angle gauge if head bolts require angle torquing.
- Safety gear: eye protection, gloves.

Important safety notes
- Always disconnect battery, relieve fuel system pressure, and drain coolant/oil if you will remove the head.
- Work in a clean area to avoid contaminating valve seats/guide bores.
- Use the factory manual for torques and clearances. Incorrect torquing or timing can destroy the engine.
- Valve seats and guides are precision parts. If you are unsure, a competent machine shop is recommended.

Step-by-step procedure (high level with detailed component actions)
Note: this is an engine-level repair. Exact sequences and some component names vary on the 4M50 — use the factory manual for torque values, timing procedures, and final clearances.

1) Preparation and removal — expose the head and valve train
- Drain coolant and engine oil if required by head removal.
- Remove intake and exhaust manifolds, turbocharger hardware if applicable, EGR plumbing, injectors or rocker cover, rocker arms/buckets, timing covers, and timing components as required to remove the head (follow manual).
- Tag and bag electrical connectors, bolts and hoses to avoid reassembly mistakes.
- Mark orientation of camshafts/rocker assemblies and timing marks — take photos. Keep timing components assembled or mark their relative positions.
- Remove the cylinder head: loosen head bolts in the sequence and steps specified by the manual (usually progressive steps in reverse of torque sequence). Remove head and place on a clean, flat workbench.

2) Inspect valves and seats before disassembly
- With head off, inspect valve seats, valve faces, guide bores for obvious damage. If seats are badly pitted or valves burned, you may need seat work.
- Decide whether to replace just guides, or guides + seats + valves. If stems are scored or badly worn, replace valves too.

3) Remove valves, springs, and retainers
- Use a valve spring compressor to compress springs and remove keepers (collets). Keep valves, springs, retainers paired and labeled for their original positions and orientation.
- Remove valves and label them with the cylinder/position they came from (important to preserve matched wear patterns).

4) Remove old valve guides
- The guide removal method depends on the fit and shop practice:
- Heat-the-head method: heat the head in an oven to controlled temperature (e.g., 120–200°C — consult shop data; do NOT overheat past safe limits) to expand head metal and reduce interference fit. Use a press or driver to push the guide out from the combustion-side toward the outside or per manual direction. This reduces risk of cracking seats.
- Press-out cold: use arbor press and driver sized to the guide OD; push the guide straight out. Support the head evenly under the guide to avoid distorting valve seats.
- Drive-out: use a correct-diameter drift and a hammer — this is the least preferred because it risks damage.
- Always support the head under the guide bore while removing. Use a driver that contacts only the guide and not the head face.
- After removal, inspect the guide bores for damage and clean thoroughly. Remove carbon and corrosion using proper brushes and solvent—keep debris out of coolant passages.

5) Prepare and install new guides
- Measure new guide OD and head bore. New guides are interference-fit — the correct installation method is critical.
- Common installation methods:
- Heat head and press guide in cold.
- Pre-chill guide (freezer) and press into room-temperature head.
- Use an induction heater or oven and an arbor press to control expansion/fit.
- Insert guide straight and press to the correct depth (guides have a specified protrusion above the head deck). Use a depth gauge and the driver that seats on the guide collar, not the head casting.
- Clean the bore and re-check protrusion. Incorrect protrusion or angled insertion can cause valve misalignment.

6) Final sizing (reaming) and clearance measurement
- New guides are usually installed slightly undersize ID and require reaming to final diameter for correct valve stem clearance.
- Measure valve stem diameters with a micrometer (take multiple readings along stem). Calculate desired clearance per manual (example: clearance is small — a few thousandths of an inch/mm). Do not guess — refer to manual clearance specs for the 4M50.
- Ream the guide carefully with the correct reamer for the guide-press fit, following reamer manufacturer instructions (use cutting oil, control feed rate, keep reamer perfectly straight).
- After reaming, measure the guide bore with an inside micrometer or telescoping gauge and micrometer. Verify stem-to-guide clearance across multiple heights of the guide bore.
- Check valve stem runout and that the valve slides freely without binding but with minimal side play.

7) Valve seats and valve faces
- If guides were worn a long time, the valve seats may be worn. Check seat contact pattern using engineer’s blue or a light lapping compound. If seats require cutting, use proper seat cutters or have a machine shop cut the seats concentric to the new guides.
- If cutters are used, ensure concentricity with the guide bore — a slight misalignment causes sealing problems.

8) Install valve stem seals
- Replace valve stem seals with new OEM-style seals. Fit seals loosely over guides and ensure they seat fully. Some seals require heating or lubrication to slide on—follow part instructions.

9) Reassembly of valves into the head
- Lightly lubricate valve stems with oil and slide each valve into its original position (or replace valves as needed).
- Compress springs and install retainers and keepers. Ensure collets seat properly and springs are correctly oriented.
- Rotate the valve by hand and ensure no binding at any point of travel.

10) Reinstall camshaft, timing, and final assembly
- Refit camshafts/rockers/lifters per manual. If camshafts were removed, check cam bearing torque, endplay, and timing marks.
- Replace head gasket and install head bolts. Use new bolts if torque-to-yield. Torque head bolts in the prescribed multi-step sequence and angles per the manual.
- Reinstall timing belt/chain, align timing marks precisely. If timing is off, engine will be badly damaged on running.
- Reconnect manifolds, injectors/fuel lines, coolant lines, and sensors. Refill coolant and engine oil (change oil filter if oil contaminated by debris).
- Adjust valve lash or preload per the 4M50 procedure (if the engine uses shims/buckets or hydraulic lifters, follow the specific procedure).

11) Testing and verification
- Prime fuel if fuel system drained. Crank engine without fuel (or with blocked injectors per manual) to build oil pressure before starting.
- Start engine and listen for abnormal noises. Check for oil leaks, coolant leaks.
- Perform compression or leak-down test to verify sealing.
- Check oil consumption and smoke over first hours of running. Re-check valve clearance/timing if required.

Measurements & clearances (must use the manual for exact 4M50 values)
- Valve stem-to-guide clearance, seat contact width, valve stem protrusion above head deck, guide protrusion are all specified in the manual. Example of what to measure:
- Valve stem diameter at several points.
- Guide inner diameter after reaming.
- Clearance (guide ID minus stem OD).
- Guide protrusion above head surface.
- Valve spring installed height and pressure.
- Never rely on “typical” numbers without confirming for 4M50 — errors can lead to seized valves or oil burning.

What can go wrong (and how to avoid it)
- Breaking or cracking the head while heating or pressing: avoid localized overheating; support head correctly; use controlled ovens or induction heaters and a press, not hammering.
- Distorting valve seats or boss while pressing guides: always support head under the bores; press straight; check seat concentricity.
- Wrong guide insertion depth or angle: results in valve misalignment and poor sealing. Measure protrusion and check alignment.
- Over-reaming: creates excessive clearance, causing oil burning and premature wear. Ream only to the specified final size and measure often. Use reamer stops or jig.
- Improper valve stem seals or seating: leads to oil leaking down the stem — replace seals and ensure seating.
- Reassembly with incorrect timing or torque: catastrophic. Follow the factory timing procedure and torque sequence/angles.
- Contamination: metal shavings from reaming can contaminate coolant, oil, or valves. Clean thoroughly and change oil/filter before running.
- Using wrong materials: non-hardened guides or improper interference fit will fail quickly. Use OEM or correct-spec guides.

When to send it to a machine shop
- If valve seats need recutting or installation that requires specialized seat equipment to ensure concentricity to the new guides.
- If you don’t have a press, induction heater, reamer jigs, or the skills to control reaming.
- If heads are cracked or badly corroded.
- A machine shop will install guides, cut seats, and ensure concentricity using fixtures.

Final checklist before first start
- All bolts torqued to spec, timing aligned, no leftover parts.
- New valve stem seals installed.
- Cleaned head and removed all metallic debris; oil changed and filter replaced after machining work.
- Fluid levels correct and no leaks.
- Crank without fuel or ignition as per manual to build oil pressure before first start.

Concise troubleshooting after reassembly
- Blue smoke at startup that clears quickly: likely residual oil; acceptable to a point.
- Continuous blue smoke: valve seals/guides clearance too big, or seals not installed, or guide installed incorrectly.
- Rough idle/compression loss: check valve seating, timing, and valve stem runout.
- Loud tapping or clatter: check valve lash/tappet adjustment or cam timing.

Closing — key points for a beginner mechanic
- Valve-guide replacement is precision work. The critical tasks are correct guide installation depth, careful reaming to exact diameter, and preserving concentricity between guide and seat.
- Always use the Mitsubishi 4M50 factory service manual for torque values, timing procedures, and clearance specs. If you lack a press, reamer, or measurement tools, use a qualified machine shop for guide installation and seat work.
- Work methodically: label everything, keep parts in order, and clean thoroughly. Safety and cleanliness are as critical as correct measuring.

No extra questions — follow the factory manual for 4M50 specifics.
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Tools & consumables
- Metric socket set (8–19 mm), 3/8" and 1/2" ratchets and extensions
- Combination wrenches and metric line/flare-nut wrenches (8, 10, 12, 14 mm as needed)
- Torque wrench (range to 5–120 Nm)
- Screwdrivers (flat & Phillips)
- Pliers, snap‑ring pliers or small punch for retaining pin/clip
- Brake/clutch vacuum bleeder or hand vacuum pump with reservoir adapter
- Bleed tube and clear catch bottle
- Bench-bleed kit or short silicone hoses and clamps
- Drain pan and shop rags
- Funnel and DOT fluid recommended by OEM (usually DOT 4 — verify manual)
- New crush washers for banjo bolt(s) or new hard‑line fittings if applicable
- New master cylinder assembly (complete unit) with reservoir if replacing; new pushrod boot/pedal pin/clip if worn
- Clean gloves, safety glasses, brake parts cleaner, waste container for fluid
- Jack and heavy‑duty stands or truck lift (if required to access pedal area)
- Wire ties or clamps to secure hoses

Safety precautions (no exceptions)
- Work on level ground; chock wheels and set parking brake.
- Disconnect battery negative if working near electrical harnesses or to prevent accidental start.
- Wear eye protection and gloves; brake/clutch fluid is corrosive — avoid skin/paint contact.
- Contain and dispose of fluid properly; protect painted surfaces (use cardboard/cloth).
- Support vehicle securely if raised. Never rely on a jack alone.

Parts required (typical)
- Replacement clutch master cylinder assembly (OEM part number for Mitsubishi Fuso FE/FG 4M50)
- New banjo crush washers or line sealing washers (2x per banjo bolt if used)
- Replacement pedal pin/clip, pushrod boot if worn (recommended inspection)
- DOT‑specified hydraulic fluid

Step‑by‑step procedure
1) Preparation
- Park truck, chock wheels, open bonnet. Remove engine cover or components as required for access to master cylinder reservoir (usually on firewall/driver side).
- Place drain pan beneath the hydraulic line connection points and prepare rags.
- Clean around reservoir cap before opening to prevent contamination.
- Remove reservoir cap and siphon out as much fluid as possible with a suction tool to reduce spillage.

2) Access & disconnect
- Trace hydraulic line from reservoir/master cylinder to the slave cylinder or hard line. Identify banjo bolt or flare nut connection.
- Using a line/flair-nut wrench, loosen the hydraulic line fitting or banjo bolt. Catch fluid into pan; immediately plug line/openings with clean caps or rags to prevent contamination.
- Remove any retaining clips, brackets, or electrical connectors attached to the master cylinder/reservoir.
- From inside cab: locate the clutch pedal connection to the master cylinder pushrod. Remove clevis pin/retaining clip or spring clip that connects pushrod to pedal. Support the pedal to prevent sudden movement.

3) Remove master cylinder
- Remove mounting bolts that secure the master cylinder body to the firewall/clutch bracket (typically 2 or 3 bolts). Use appropriate socket/wrench.
- Pull master cylinder straight out; be careful not to spill residual fluid onto paint. If the reservoir is separate, remove the reservoir hoses and clamp.

4) Prepare new master cylinder (bench-bleed)
- Always bench‑bleed a new or rebuilt master cylinder before installation. Secure the new master cylinder in a vice (soft jaws) or on a bench stand so it’s stable but not clamped on the piston.
- Attach the bench‑bleed kit hoses to the outlet ports and route them back into the reservoir. Fill reservoir with clean DOT‑specified fluid to recommended level.
- Using the supplied bleed tool or the piston rod, slowly depress the master cylinder piston repeatedly until bubbles stop appearing in reservoir and exhaust is bubble‑free. Keep fluid topped up to prevent drawing air.
- If the new unit has removable ports, install new crush washers onto banjo bolt(s) at this time.

How each tool is used
- Flare‑nut wrench: grips hydraulic fittings without rounding flats; use for loosening/tightening hard‑line nuts.
- Torque wrench: tighten mounting bolts and banjo bolts to specified torque (see notes below) to avoid leaks or stripped threads.
- Vacuum bleeder: connects to bleed nipple on slave cylinder and draws fluid/air out while an assistant operates pedal or you actuate piston.
- Bench‑bleed kit: small hoses looped from outlet ports back into reservoir so pushing the piston forces fluid through ports and removes air before installation.
- Catch bottle & clear hose: allows you to observe bubbles and collect expelled fluid.

5) Install new master cylinder
- Position the new master cylinder onto the firewall/bracket and thread mounting bolts by hand.
- Tighten mounting bolts to specified torque. Typical values (confirm with OEM manual): M8 bolts ~20–30 Nm, M10 bolts ~40–60 Nm. Torque to exact spec from Fuso workshop manual if available.
- Reconnect hydraulic line(s) using new crush washers on banjo bolts. Tighten banjo bolt to typical torque ~25–35 Nm (confirm OEM spec). If line uses flare nut, tighten to proper torque gently — do not overtighten.
- Reconnect reservoir hoses if separate and secure clamps.

6) Reconnect pushrod to pedal
- With master cylinder fully seated/pushed to normal stroke position, connect pushrod clevis to pedal and install pin and retaining clip. Adjust pushrod free play per factory spec (usually a small clearance; ensure pedal engages slave correctly). If adjustment is required, set per manual.

7) Initial bleeding (in‑vehicle)
- Fill reservoir to correct level with fresh fluid.
- Use one of these recommended bleeding methods:
a) Vacuum bleed at slave: Attach vacuum pump to slave bleed nipple. Open nipple, pump until no air and clear fluid flows. Close nipple while maintaining vacuum. Cycle pedal slowly 8–10 times and recheck.
b) Pedal‑assist (two‑person): Assistant pumps pedal several times, holds it depressed. Open slave bleed nipple briefly to let air/fluid out, close nipple, repeat until no air. Keep reservoir topped up.
c) Pressure bleeder: Follow manufacturer procedure.
- Work from slave toward master (if there are intermediate lines/valves, follow OEM sequence). Continue until pedal feels firm and travel is correct.

8) Final checks & adjustment
- With system bled and bleed nipple closed, cycle pedal for feel. Check for leaks at banjo/line connections and mounting area.
- Verify pedal free play and engagement point, adjust pushrod if necessary.
- Clean spilled fluid and touch‑up any paint damage immediately.
- Test drive at low speed to confirm proper clutch operation. Recheck fluid level and for leaks after test.

Common pitfalls / things that ruin the job
- Not bench‑bleeding the new master cylinder: this traps air in the master and makes in‑vehicle bleeding long or impossible.
- Using the wrong fluid or contaminated fluid: always use OEM specified DOT grade; don’t mix if not compatible.
- Rounding soft hydraulic fittings: use flare‑nut wrenches, not open‑end or adjustable pliers.
- Reusing crush washers on banjo bolts: always replace crush washers to get a proper seal.
- Over‑tightening banjo bolt or line fittings: can strip threads or crack fitting; use torque wrench and OEM specs.
- Leaving the reservoir low during bleeding: introduces air back into system.
- Not checking pedal pushrod length/free‑play: incorrect adjustment can leave clutch slipping or not disengaging.
- Spilling fluid on paint and not cleaning immediately: brake fluid removes paint — treat spills promptly.
- Not checking for internal leaks or contamination in slave cylinder or pipes: if contaminated, replace affected parts.

Torque & spec notes
- Always verify exact bolt and banjo torque values and fluid spec from the Mitsubishi Fuso FE/FG 4M50 workshop manual. The values provided above are typical ranges only — use factory values when available.

Disposal
- Collect old fluid and contaminated rags; dispose of as hazardous waste per local regulations.

Wrap‑up checklist before returning truck to service
- Master cylinder securely mounted and torqued
- Hydraulic lines tight; new crush washers installed
- Pedal pushrod connected and adjusted
- System bled until pedal firm, no air present
- No external leaks, fluid level correct
- Test drive verified clutch operation

Done.
rteeqp73

Replacing the head gasket on a Mitsubishi 4M50 engine (commonly found in FE FG Fuso trucks) involves several critical steps, each addressing specific issues related to head gasket failure. Here’s a structured explanation of the process and the theory behind it:

### Understanding the Head Gasket Function

- **Function**: The head gasket seals the combustion chamber, ensuring that the high-pressure gases from combustion do not escape into the cooling system or oil passages. It also prevents coolant and oil from mixing.
- **Failure Symptoms**: Symptoms of a failing head gasket can include engine overheating, loss of power, coolant in the oil, oil in the coolant, or white smoke from the exhaust.

### Steps to Replace the Head Gasket

1. **Preparation and Safety**:
- Disconnect the battery and ensure the engine is cool to prevent burns and electrical hazards.
- Drain the coolant and oil. This prevents contamination and makes handling easier.

2. **Remove Components**:
- **Intake and Exhaust Manifolds**: These must be removed to access the cylinder head. Label parts for easier reassembly.
- **Fuel Lines and Electrical Connections**: Disconnect these to avoid damage and ensure clear access to the cylinder head.
- **Accessory Components**: Remove any parts attached to the cylinder head, such as the turbocharger, if applicable.

3. **Cylinder Head Removal**:
- **Unbolt the Cylinder Head**: Follow a specific sequence to prevent warping. Start with the outer bolts and work inward, loosening them gradually.
- **Lift the Cylinder Head**: Carefully lift it off the engine block, ensuring no debris falls into the engine.

4. **Inspect Engine Components**:
- **Check Cylinder Head and Block**: Look for warping or cracks. A straight edge can help determine flatness. Resurfacing may be necessary if the head is warped.
- **Inspect Pistons and Cylinder Walls**: Check for scoring or damage.

5. **Clean Surfaces**:
- Remove old gasket material from both the cylinder head and engine block. Use a scraper carefully to avoid gouging the metal surfaces. Cleanliness is crucial for proper sealing.

6. **Install New Head Gasket**:
- Place the new gasket on the engine block. Ensure it is oriented correctly according to manufacturer specifications.

7. **Reinstall the Cylinder Head**:
- Carefully place the cylinder head back onto the block, aligning it with dowel pins.
- **Torque the Bolts**: Follow the manufacturer’s specified torque sequence and specifications. This ensures even pressure across the gasket, preventing leaks.

8. **Reassemble Engine Components**:
- Reinstall the intake and exhaust manifolds, fuel lines, and any accessory components removed earlier. Ensure all connections are tight and leak-free.

9. **Refill Fluids**:
- Refill the engine oil and coolant. This includes checking for any specific coolant types recommended by the manufacturer.

10. **Test the Engine**:
- Reconnect the battery and start the engine. Allow it to reach operating temperature while checking for leaks. Monitor temperature and oil pressure.

### Theory Behind the Repair

- **Sealing**: The new head gasket creates a proper seal between the cylinder head and the engine block, preventing the mixing of coolant and oil, and ensuring high-pressure combustion gases remain contained.
- **Heat Management**: A properly installed head gasket assists in managing the engine's thermal dynamics, ensuring efficient operation and preventing overheating.
- **Integrity of Components**: By inspecting and resurfacing the cylinder head and block, you ensure that the mating surfaces are smooth and flat, which directly affects the gasket's ability to seal effectively.

### Conclusion

Replacing the head gasket on a Mitsubishi 4M50 engine is not just about following steps; it involves understanding the role of each component and the importance of proper assembly and sealing to maintain engine integrity and performance. This repair rectifies the failure modes associated with a blown head gasket, restoring the engine's functionality and reliability.
rteeqp73