Caterpillarexcavator

Caterpillar E70

Maintenance schedule, common problems & OEM parts breakdown

The Caterpillar E70 is a crawler-mounted mini/midi hydraulic excavator in the roughly 6.5 to 7 tonne (14,300 to 15,260 lb) operating weight class. The base E70 runs a Mitsubishi 4D31 diesel rated near 52 hp; the updated E70B carries the Mitsubishi 4D32, rated slightly higher near 54 hp, paired with a small increase in operating weight. Production dates back to the late 1980s as part of Caterpillar's first-generation E-series line, a family that also included the E110, E120, E140, E180, E200B, E240, E300, E450, and E650 in ascending size classes. The E70 was offered with different bucket and arm combinations for trenching, utility, and general digging work, and both canopy and enclosed-cab configurations were sold depending on region and dealer order.

The move from E70 to E70B centered on the engine upgrade and modest weight and capacity gains, with the rest of the crawler chassis, swing frame, and hydraulic architecture carried forward largely unchanged. Because the E-series predates Caterpillar's electronic engine and machine monitoring systems, these excavators run fully mechanical fuel systems and open hydraulic circuits, which keeps diagnostics simple and keeps the machines serviceable well past the age where more electronic-heavy compact excavators become parts-dependent. That mechanical simplicity, combined with decades of used units still circulating through secondary and export equipment markets, keeps demand steady for undercarriage, hydraulic, and driveline parts, and the E70 platform remains a common donor and rebuild candidate in the compact excavator parts trade today.

Below: full specifications, fluids & capacities, the factory service schedule, common service parts, verified fault codes, what owners discuss, attachment guidance, the complete assembly directory, and a serial-number reference. Complete parts lists with full OEM part numbers, exploded diagrams, quantities, and fitment data are available free in Heavy Parts AI.

Caterpillar E70 specifications

Engine

Engine model	Mitsubishi 4D31 diesel, inline-4. This is the first-generation E-series midi excavator, in production from 1987, preceding the later E70B generation (which switched to a Mitsubishi 4D32).
Net/flywheel power	52 hp (38.8 kW) flywheel rated
Displacement	Not documented for this generation on an E70-specific sheet. General Mitsubishi 4D31 engine reference literature lists approx. 3.3 L (201 cu in), but that figure is not confirmed against a machine-specific document, so treat as indicative only
Cylinders	4
Emissions tier	Predates formal emissions-tier standards for this equipment class - the machine's 1987-1994 production run is before the first U.S. nonroad diesel standard (Tier 1), which was adopted in 1994 and phased in from 1996

Weights

Operating weight (standard configuration)	6,486 kg (14,300 lb)
Ground pressure	Not documented for this generation - varies by track shoe width and configuration
Transport weight	Not documented separately from operating weight

Dimensions

Transport length	6.02 m (19 ft 9 in)
Transport width	2.26 m (7 ft 5 in)
Transport height	2.59 m (8 ft 6 in)
Tail swing radius	Not documented for this generation
Track shoe width	Not documented for this generation
Ground clearance	Not documented for this generation
Undercarriage length	Not documented for this generation

Performance

Hydraulic control system	Variable-flow hydraulic system with mechanical implement controls. Optional offset boom and an increased-horsepower travel option were offered.
Max dig depth	Not documented for this generation - factory figures have not surfaced; do not assume later-generation values carry over
Max reach at ground	Not documented for this generation
Max dump height	Not documented for this generation
Max cutting height	Not documented for this generation
Swing speed	Not documented for this generation
Travel speed	Not documented for this generation
Gradeability	Not documented for this generation
Drawbar pull	Not documented for this generation

Forces

Bucket digging force	Not documented for this generation
Stick/arm digging force	Not documented for this generation

Service capacities (summary)

Fuel tank	Not documented for this generation
Hydraulic system/tank	Not documented for this generation
Engine oil	Not documented for this generation
Cooling system	Not documented for this generation

Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.

E70 fluids & capacities

System	Capacity	Recommended fluid
Engine crankcase (with filter)	Approximately 9 L (2.4 US gal), reported for the E70-family chassis; not independently confirmed for the base 4D31-engine E70 apart from the later E70B (4D32) configuration — treat as approximate.	Cat DEO (Diesel Engine Oil). SAE 15W-40 for general/warm-climate service, dropping to SAE 10W-30 below roughly -18 C (0 F) per Cat's standard multigrade guidance for this engine class. Confirm the exact viscosity chart against the OMM for the specific serial prefix.
Cooling system	Approximately 16 L (4.2 US gal), reported for the E70-family chassis; not separately confirmed for the base E70 versus E70B.	Full-strength or premixed ethylene-glycol antifreeze/coolant with a supplemental coolant additive, consistent with this era's Cat coolant practice (predates wide OMM adoption of Cat ELC). Mix ratio per ambient-temperature protection level in the OMM.
Fuel tank	Approximately 110 L (29.1 US gal), consistent across E70-family spec sources; not separately confirmed for the base 3BG-prefix E70 versus the later E70B, but likely shared given the common chassis.	No. 2-D diesel fuel for normal ambient conditions. Switch to No. 1-D or a winter-blend diesel below freezing to prevent fuel waxing/gelling.
Hydraulic system total (incl. tank)	Approximately 105 L (27.7 US gal) reported in a single spec source for this chassis — unverified against a second independent source and not confirmed for the base E70; treat as an approximate reference only, varies by configuration/series. A pump-flow rating of about 134 L/min (35.4 US gpm) is sometimes quoted alongside this figure — that is pump output, not tank fill volume, and should not be confused with it.	Cat TDTO (Transmission/Drive Train Oil) has historically doubled as the hydraulic fluid on this excavator class; where the OMM allows it, Cat HYDO Advanced is the modern-equivalent preferred hydraulic fluid. Match viscosity to the OMM's ambient-temperature chart.
Hydraulic tank (reservoir only)	Not separately broken out from the total hydraulic system figure in available sources for this model.	Same fluid as hydraulic system total (Cat TDTO or Cat HYDO Advanced per OMM).
Final drive (each)	Not documented in available sources for this model — verify against the OMM lubrication chart or dealer.	Cat TDTO. Grade by ambient temperature per this platform's OMM chart: SAE 30 in cold service (roughly -20 to 25 C / -4 to 77 F), SAE 40 for a mid range (roughly -10 to 40 C / 14 to 104 F), SAE 50 for warm service (roughly 0 to 50 C / 32 to 122 F).
Swing drive	Not reliably documented — one source gives a small figure of roughly 4 L against an ambiguously labeled component; treat as unconfirmed pending direct OMM verification.	Same Cat TDTO fluid and climate-based viscosity chart as the final drives (SAE 30/40/50 by ambient temperature) — the swing gear reduction shares the same lubricant spec on this platform.
Pilot / other circuits	No separate reservoir or capacity documented; the pilot control circuit draws from the main hydraulic tank on this excavator class.	Same hydraulic fluid as the main hydraulic system.
Grease (spec only)	Not applicable — lubricated per the OMM's grease-point schedule at boom/stick/bucket linkage pins, bushings, and the swing-gear bearing.	Cat Multipurpose Grease (NLGI grade 2, lithium-complex, petroleum base, EP-rated). Use Cat Extreme Application grease for high-load pin/bushing points on heavy duty cycles.

Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.

Caterpillar E70 maintenance schedule

Service interval	Tasks
Every 10 h	Check engine oil level and coolant level before starting the shift Walk around the machine and check for fresh fuel, oil, or hydraulic leaks Drain water and sediment from the fuel water separator Grease boom, stick, and bucket pivot pins and bushings Check track tension and clear packed dirt or debris from the undercarriage Check hydraulic oil level at the sight gauge with the arm in the retracted travel position
Every 250 h	Change engine oil and replace the engine oil filter Check and adjust alternator and fan belt tension Service or replace the primary air cleaner element as indicated Check battery terminals, cable condition, and electrolyte level Check swing drive gear case oil level
Every 500 h	Replace the fuel filter element and bleed the fuel system Change final drive (travel gear case) oil in both track motors Check and re-torque track shoe bolts to spec Clean radiator and oil cooler fins of mud and debris Test coolant condition and correct antifreeze concentration
Every 1,000 h	Replace the hydraulic tank return filter and breather Change swing drive gear case oil Check and adjust engine valve lash Torque all boom, stick, and bucket linkage pin retainers Pull an engine oil and hydraulic oil sample for analysis
Every 2,000 h	Replace hydraulic tank oil and clean or replace the suction strainer Replace engine coolant or test extended-life coolant condition and additive level Inspect the fuel injection pump and injectors for wear, have them tested off-machine Inspect the swing bearing and swing gear teeth for wear or play Inspect track rollers, idlers, and sprockets against wear-limit gauges
Every 4,000 h	Rebuild or exchange the hydraulic pump and main control valve if flow or response has degraded Replace track chains, rollers, idlers, and sprockets once wear limits are reached Overhaul travel motor and swing motor seals and bearings Recondition the engine top end, including cylinder head and injectors, at major overhaul Replace the full hydraulic hose set as a preventive measure regardless of visible condition

Servicing the E70 beyond the schedule

Predictive Maintenance & Fluid Analysis

The E70's Mitsubishi 4D31/4D32 diesel and open hydraulic circuit have no onboard diagnostics, so scheduled oil sampling is the main early-warning tool. Pull engine oil, hydraulic oil, and gear case oil samples at each major interval and watch for rising metal content, which flags travel motor or swing gear wear before it reaches the pump or valve. Track coolant condition and fuel filter debris closely, since a clogged fuel water separator is the most common cause of unexplained power loss on these small mechanical diesels.

Corrective & Common Repairs

Expect wear in the swing bearing, travel motor final drives, and pivot bushings on high-hour E70/E70B units, since these carry the load in a compact frame built for utility digging. Fuel injection pump and injector wear shows up as hard starting or smoke and typically needs bench testing rather than field adjustment. Hydraulic cylinder seal leakage at the boom and stick is common once seals age past their service life, and control valve spool wear can cause sluggish or drifting arm movement under load.

Overhaul & Rebuild Points

A full undercarriage rebuild - rollers, idlers, sprockets, and track chain - is the most frequent major job on this crawler platform once wear-limit gauges are exceeded. Major overhauls should also address the hydraulic pump and main control valve as a set, since one worn component accelerates wear in the other on this open-center system. Engine top-end work on the 4D31/4D32 (head, valves, injectors) is a common rebuild point once compression and oil consumption fall off, and swing and travel motor seal kits are typically replaced together at overhaul.

Seasonal & Environment Servicing

In cold climates, use the correct viscosity engine oil and check block heater or glow system function before winter, since the mechanical Mitsubishi diesel can be hard-starting below freezing. In hot or dusty conditions, clean radiator and oil cooler fins more often and shorten air filter service intervals to protect the naturally aspirated engine from dust ingestion. Wet or muddy sites call for more frequent undercarriage washouts and track tension checks, since packed mud accelerates roller and idler wear on this size of crawler chassis.

E70 common service parts

Part number	Part	Notes
096-9013	Gasket, Fuel Filter	Fuel system service	Check fitment →

Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.

E70 fault codes & troubleshooting

Code	Meaning	Likely cause	What to do
Charging system warning light (alternator symbol)	Battery not charging / charging circuit fault	Failed alternator, worn or slipping belt, loose or corroded wiring at the alternator or battery	Check belt tension, inspect wiring and connections, test alternator output with engine running
Engine oil pressure warning light (oil can symbol)	Low engine oil pressure	Low oil level, worn oil pump or bearings, failed pressure sender/switch, blocked oil passage	Shut engine down immediately, check oil level and condition, verify pressure with a mechanical gauge before restarting
Coolant temperature warning light (thermometer symbol)	Engine coolant temperature above normal operating range	Low coolant level, blocked or dirty radiator, failed thermostat, faulty temperature sender, slipping fan belt	Let engine cool, check coolant level and radiator fins, inspect thermostat and sender, check fan belt and drive
Control warning light with alarm	Fault or lockout condition in the pilot hydraulic control circuit for the joysticks	Safety lockout lever left engaged, low pilot system pressure, faulty pilot pressure switch or its wiring	Confirm the safety lockout lever is fully released, check pilot pressure at the accumulator, inspect the pressure switch and connector
Warning buzzer (continuous, triggered with any lit warning light)	Audible alert paired to whichever warning light is active	Same as the associated light (charging, oil pressure, coolant temperature, or control fault); buzzer/lights can also stay lit together if the dash test circuit is stuck on	Identify which lamp is lit first, address that system, then press the dash test button to confirm all lamps and buzzer reset correctly
Hydraulic oil temperature gauge in red/warning zone	Hydraulic system oil running hotter than normal operating range	Low hydraulic fluid level, clogged or dirty oil cooler, relief valve stuck open, worn main pump generating excess heat	Check hydraulic fluid level and condition, clean cooler fins, verify relief valve settings and case-drain temperature
Air cleaner restriction indicator	Air filter element loading up, restricting intake airflow	Dirty or clogged air filter element, damaged intake ducting	Inspect and clean or replace the air filter element, check intake hoses and clamps for leaks or damage
Fuel level warning light	Fuel tank level low	Tank running low during operation, fuel gauge sender fault if light stays on with a full tank	Refuel; if light stays on after refueling, check the fuel level sender and wiring

Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.

E70 attachments & work tools

Buckets

Pin-on bucket-to-dipper pin measures about 44.8 mm (1.76 in) diameter, a dimension shared across the E70/E70B and the contemporaneous 307/307B/307C dipper geometry. General-purpose bucket widths for this class typically run 600-900 mm (24-36 in), with heaped capacity roughly 0.18-0.40 cubic meters (0.23-0.53 cubic yards) spanning GD digging buckets up to HD/rock profiles; exact capacity varies by configuration and bucket width chosen.

Hydraulic hammers

This machine falls in the 6.5-7.8 tonne operating weight window, which lines up with the compact hammer class built for 5-9 tonne mini/midi excavators (around 390 kg tool weight, roughly 1085 J working energy class). Match breaker weight to the E70's lift and hydraulic capacity rather than stepping up to a full-size excavator hammer, which will overload this carrier.

Quick couplers

Mechanical or hydraulic pin-grabber couplers sized for the 7-10 tonne excavator class fit the E70's dipper pin spacing, letting the operator swap bucket/thumb/hammer without leaving the cab on hydraulic versions. A hydraulic tilting pin-grab coupler was also offered across this Cat midi-excavator lineage; mechanical pin-grabber kits (wrench and locking bolt) remain the simpler, cheaper option for this size class.

Thumbs/grapples

Hydraulic or mechanical thumb kits sized around 900 mm (36 in) are the common fit for excavators in the 5,400-7,300 kg (12,000-16,000 lb) range that the E70/E70B occupies, bolting to the same dipper pin used by the bucket. Orange-peel or vertical grapples exist in the Cat excavator lineup but published capacity classes start around 14 tonnes and up; no grapple model is specifically documented for the E70 size class, so treat grapple fitment as verify-with-dealer rather than confirmed.

Rippers

Single-shank ripper attachments built for the 307/308 size class use the same coupler/pin geometry as the E70 and are intended for breaking up compacted or frozen ground and light frost crust, not rock ripping. Given the E70's power class (roughly 52-55 hp Mitsubishi diesel, varies by source/generation), keep ripper use to soil conditioning rather than hard-rock work.

Hydraulic kit notes

The E70/E70B hydraulic system is a variable-flow circuit with a Power/Work mode selector and pilot-activated controls, not a factory high-flow circuit. A single-direction auxiliary line (dealer or factory-fitted) is what feeds a hammer or single-acting thumb cylinder; there is no documented high-flow kit for this model, so plan attachment selection around standard-flow tools only.

All E70 assemblies by section

Every catalogued assembly group for the Caterpillar E70. Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.

Engine

Alternator

Alternator General

Breather And Oil Filler

Camshaft

Connecting Rod And Bearing

Crankshaft And Pulley

Crankshaft Bearing

Cylinder Block - (Part 1 Of 2)

Cylinder Block - (Part 2 Of 2)

Cylinder Block Repair Kit

Cylinder Head

Cylinder Head Repair Kit

Engine Attaching Parts

Engine Gasket Kit

09***90	Gasket, Cylinder Head	1
09***14	Gasket, Rocker Cover	1
09***21	Gasket, Re. Plate	1
09***31	Gasket, Gear Case	1

See all parts with full part numbers in Heavy Parts AI →

Engine Hanger

Engine Oilseal Kit

Exhaust Manifold

Exhaust Muffler

Exhaust Pipe

Fan And Pulley

Flywheel

Flywheel Housing

Fuel Feed Pump - Part 2 Of 2

Fuel Feed Pump - Part 1 Of 2

Fuel Filter

Fuel Hose

Fuel Injection Nozzle - Part 1 Of 2

Fuel Injection Nozzle - Part 2 Of 2

Fuel Injection Pipe

Fuel Injection Pump General

Fuel Return System

Governor - Part 1 Of 4

Governor - Part 3 Of 4

Governor - Part 2 Of 4

Governor - Part 4 Of 4

Injection Pump

Inlet Manifold

Instrument

Liner And Piston Kit

Name Plate

Oil Cooler - Part 1 Of 2

Oil Cooler - Part 2 Of 2

Oil Filler And Oil Level Gauge

Oil Filter

Oil Line

Oil Pan

Oil Pressure Switch And Gauge Unit

Oil Pump And Gear Train

Oil Strainer

Piston

Rocker Cover

Starter - Part 1 Of 2

Starter - Part 2 Of 2

Starter (For Cold Weather) - Part 2 Of 2

Starter (For Cold Weather) - Part 1 Of 2

Starter General

Timing Gear

Timing Gear Case

Valve Gear Train

Water Pipe And Thermostat

Water Pump

Water Temp Gauge Unit

Vehicle

Accumulator (3bg1-09117)

Adjuster Cylinder

Air Cleaner

Air Conditioner - Part 2 Of 3

Air Conditioner - Part 3 Of 3

Air Conditioner - Part 1 Of 3

Air Conditioner Compressor

Air Conditioner Condenser And Receiver

Air Conditioner Harness

Air Conditioner Lines

Am/Fm Radio (3bg1-09076 Std. 3bg09077- O.P.)

Arm And Bucket Lines

Arm Cylinder (For Power Drive Offset Boom)

Arm Cylinder - Part 1 Of 2

Arm Cylinder - Part 2 Of 2

Auto Lock (3bg1-09107)

Bank Forming Bucket

Base Frame

Base Frame (For Blade)

Blade

Blade Cylinder - Part 2 Of 2

Blade Cylinder - Part 1 Of 2

Boom And Accessories (For Power Drive Offset Boom) - Part 1 Of 3

Boom And Accessories - Part 1 Of 2

Boom And Accessories (For Power Drive Offset Boom) - Part 3 Of 3

Boom And Accessories (For Power Drive Offset Boom) - Part 2 Of 3

Boom And Accessories (For Breaker/Double Acting Actuators) - Part 2 Of 2

Boom And Accessories - Part 2 Of 2

Boom And Accessories (For Breaker/Double Acting Actuators) - Part 1 Of 2

Boom Cylinder (For Boom Lowering Check Valve) - Part 2 Of 2

Boom Cylinder - Part 2 Of 2

Boom Cylinder - Part 1 Of 2

Boom Cylinder (For Boom Lowering Check Valve) - Part 1 Of 2

Boom Light And Harness (For Power Drive Offset Boom)

Boom Light And Harness

Boom Lines

Boom Lines (For Power Drive Offset Boom/Double Acting Actuators)

Bucket - Sae 1/4 Cubic Yard (Jis 0.18 Cubic Meter)

Bucket - Sae 3/16 Cubic Yard (Jis 0.14 Cubic Meter)

Bucket - Sae 3/8 Cubic Yard (Jis 0.25 Cubic Meter)

Bucket - Sae 7/16 Cubic Yard (Jis 0.3 Cubic Meter)

Bucket Cylinder - Part 2 Of 2

Bucket Cylinder - Part 1 Of 2

Bucket With Ejector - Sae 3/16 Cubic Yard (Jis 0.14 Cubic Meter)

Cab (Interior Parts) - Part 4a Of 5

Cab (Door And Window Frame) - Part 2 Of 5

Cab (Door And Window Frame) - Part 2b Of 5

Cab (Frame) - Part 1 Of 5

Cab (Frame) - Part 1b Of 5

Cab (Frame) - Part 1c Of 5

Cab (Interior Parts) - Part 4 Of 5

Cab (Glass And Corner Rubber) - Part 3 Of 5

Cab (Door And Window Frame) - Part 2c Of 5

Cab (Window Washer) - Part 5 Of 5

Cab (Door And Window Frame) - Part 2a Of 5

Cab (Frame) - Part 1a Of 5

Cab (Frame) - Part 1d Of 5

Cab Heater

Carrier Roller

Check Valve (For Breaker)

Check Valve

Control Valve (For Blade)

Control Valve A (For Power Drive Offset Boom/Double Acting Actuators)

Control Valve A (For Breaker) - Part 2 Of 2

Control Valve A

Control Valve A (For Breaker) - Part 1 Of 2

Control Valve B - Part 1 Of 2

Control Valve B - Part 2 Of 2

Controls (For Power Drive Offset Boom) - Part 2 Of 2

Controls (For Power Drive Offset Boom) - Part 1 Of 2

Controls (For Double Acting Actuators)

Controls (For Blade)

Controls (For Breaker)

Delivery Lines (For Power Drive Offset Boom/Double Acting Actuators)

Delivery Lines - Part 1 Of 2

Delivery Lines - Part 2 Of 2

Drain Lines

Electric Parts - Part 2 Of 2

Electric Parts (For Cold Weather)

Electric Parts - Part 1 Of 2

Engine (Part 2 Of 2)

Engine (For Cold Weather)

Engine (Part 1 Of 2)

Engine (Part 2a Of 2)

Engine Control (For Automatic Engine Speed Control) - Part 2 Of 3

Engine Control (For Automatic Engine Speed Control) - Part 1 Of 3

Engine Control (For Automatic Engine Speed Control) - Part 3 Of 3

Engine Control

Engine Hood

Front Guard

Front Lines (For Boom Lowering Check Valve)

Front Lines (For Short Arm-Breaker) - Part 1 Of 2

Front Lines

Front Lines (For Power Drive Offset Boom) - Part 1 Of 2

Front Lines (For Short Arm-Breaker) - Part 2 Of 2

Front Lines (For Double Acting Actuators)

Front Lines (For Power Drive Offset Boom) - Part 2 Of 2

Front Lubrication Lines

Front Lubrication Lines (For Power Drive Offset Boom)

Fuel Tank And Fuel Lines - Part 2 Of 2

Fuel Tank And Fuel Lines - Part 1 Of 2

Grapple

Grease Bath

Head Guard

Head Rest

Hydraulic Tank - Part 1 Of 2

Hydraulic Tank - Part 2 Of 2

Hydraulic Tank (For Cold Weather) - Part 2 Of 2

Hydraulic Tank (For Cold Weather) - Part 1 Of 2

Idler Wheel

Inlet Section

Inlet Section (For Blade)

Link And Rod

Long Arm - 7'3" (2210 Mm) - Part 1 Of 2

Long Arm - 7'3" (2210 Mm) (For Double Acting Actuators) - Part 2 Of 2

Long Arm - 7'3" (2210 Mm) - Part 2 Of 2

Long Arm - 7'3" (2210 Mm) (For Double Acting Actuators) - Part 1 Of 2

Lower Structure Cover

Lower Structure Lines (For Blade) - Part 1 Of 2

Lower Structure Lines (For Blade) - Part 2 Of 2

Main Relief Valve

Name Plate And Label

Name Plate And Label (Body-Spanish)

Name Plate And Label (For Breaker)

Name Plate And Label (Body-English)

Name Plate And Label (Cab-English)

Name Plate And Label (Cab-English) (For Automatic Engine Speed Control)

Name Plate And Label (Cab-Spanish)

Name Plate And Label (Cab-Spanish) (For Automatic Engine Speed Control)

Offset Boom Cylinder - Part 1 Of 2

Offset Boom Cylinder - Part 2 Of 2

Outlet Section

Pilot Filter

Pilot Lines (For Boom Lowering Check Valve)

Port Relief Valve

Port Relief Valve (For Power Drive Offset Boom/Double Acting Actuators)

Pump - Part 9 Of 10

Pump - Part 10 Of 10

Pump--Part 4 Of 10

Pump - Part 2 Of 10

Pump--Part 3 Of 10

Pump--Part 8 Of 10

Pump (For Blade) - Part 7 Of 11

Pump--Part 6 Of 10

Pump (For Blade) - Part 10 Of 11

Pump - Part 1 Of 10

Pump--Part 7 Of 10

Pump (For Blade) - Part 2 Of 11

Pump (For Blade) - Part 3 Of 11

Pump--Part 5 Of 10

Pump (For Blade) - Part 1 Of 11

Pump (For Blade) - Part 9 Of 11

Pump (For Blade) - Part 5 Of 11

Pump (For Blade) - Part 4 Of 11

Pump (For Blade) - Part 6 Of 11

Pump (For Blade) - Part 8 Of 11

Pump (For Blade) - Part 11 Of 11

Pump Drive

Pump Suction Lines

Radiator--Part 1 Of 2

Radiator--Part 2 Of 2

Radiator (For Air Conditioner) - Part 1 Of 2

Radiator (For Air Conditioner) - Part 2 Of 2

Radiator Baffle Plate

Radio Mantle (3bg1-09076 O.P. 3bg09077- Std.)

Relay Box (For Automatic Engine Speed Control And Swing Parking Brake) - Part 2 Of 2

Relay Box (For Automatic Engine Speed Control And Swing Parking Brake) - Part 1 Of 2

Relay Box

Relief Valve (3bg09118-)

Relief Valve (3bg1-09117)

Remote Control Valve (For Automatic Engine Speed Control) - Part 2 Of 3

Remote Control Valve - Part 1 Of 2

Remote Control Valve - Part 2 Of 2

Remote Control Valve (For Automatic Enigine Speed Control) - Part 1 Of 3

Remote Control Valve (For Automatic Engine Speed Control) - Part 2 Of 2

Remote Control Valve (For Automatic Engine Speed Control) - Part 1 Of 2

Remote Control Valve (For Automatic Engine Speed Control) - Part 3 Of 3

Restriction Valve

Restriction Valve (For Long Arm) (3bg1-09104)

Restriction Valve (3bg1-09104)

Return Lines - Part 1 Of 2

Return Lines (For Boom Lowering Check Valve)

Return Lines - Part 2 Of 2

Ripper

Rotary Joint (For Blade)

Rotary Joint

Seat And Floor Mat - Part 3 Of 3

Seat And Floor Mat - Part 1 Of 3

Seat And Floor Mat - Part 2 Of 3

Seat Belt

Servo And Pilot Lines (For Automatic Engine Speed Control And Swing Parking Brake) - Part 1 Of 3

Servo And Pilot Lines - Part 1 Of 2 (3bg1-09117)

Servo And Pilot Lines - (Part 2a Of 2)

Servo And Pilot Lines (For Automatic Engine Speed Control) - Part 2 Of 3

Servo And Pilot Lines (For Automatic Engine Speed Control And Swing Parking Brake) - Part 3 Of 3

Servo And Pilot Lines - (Part 2 Of 2)

Servo And Pilot Lines - (Part 1 Of 2)

Servo And Pilot Lines (For Automatic Engine Speed Control) - Part 1 Of 3

Servo And Pilot Lines - Part 2 Of 2 (3bg1-09117)

Servo And Pilot Lines (For Automatic Engine Speed Control) - Part 3 Of 3

Servo And Pilot Lines - Part 2 Of 2 (3bg09118-)

Servo And Pilot Lines (For Automatic Engine Speed Control And Swing Parking Brake) - Part 2 Of 3

Servo And Pilot Lines - Part 1 Of 2 (3bg09118-)

Servo And Pilot Lines (For Swing Parking Brake)

Short Arm - 5'7-3/4" (1720 Mm) (For Breaker/Double Acting Actuators) - Part 2 Of 2

Short Arm - 5'7-3/4" (1720 Mm) (For Breaker/Double Acting Actuators) - Part 1 Of 2

Short Arm - 5'7-3/4" (1720 Mm)

Shut Off Valve (For Power Drive Offset Boom/Double Actuators)

Shut Off Valve

Shuttle Valve (For Automatic Engine Speed Control)

Side Mirror

Slow Return Valve (3bg09105-)

Solenoid Valve (For Swing Parking Brake)

Spacer Section

Spool Section (For Travel)

Spool Section (For Swing)

Spool Section (For Breaker)

Spool Section (For Power Drive Offset Boom/Double Acting Actuators)

Spool Section (For Bucket)

Spool Section (For Boom)

Spool Section (For Arm)

Spool Section (For Blade)

Swing Drive (For Swing Parking Brake)

Swing Drive

Swing Frame (For Breaker)

Swing Frame (For Boom Lowering Check Valve)

Swing Frame (For Power Drive Offset Boom/Double Acting Actuators)

Swing Frame And Counter Weight -- Part 3 Of 3

Swing Frame And Counter Weight - Part 1 Of 3

Swing Frame And Counter Weight - Part 2 Of 3

Swing Frame Cover (For Breaker)

Swing Frame Cover (For Vandalism Guard)

Swing Frame Cover (Side) - Part 1 Of 3

Swing Frame Cover (Side) - Part 2 Of 3

Swing Frame Cover (Side) - Part 3 Of 3

Swing Frame Cover (Support)

Swing Frame Cover (Under)

Swing Frame Cover (Upper)

Swing Gear - Part 2 Of 2

Swing Gear - Part 1 Of 2

Swing Lines

Swing Motor (For Swing Parking Brake) - Part 3 Of 4

Swing Motor (For Swing Parking Brake) - Part 2 Of 4

Swing Motor - Part 3 Of 3

Swing Motor - Part 1 Of 3

Swing Motor (For Swing Parking Brake) - Part 4 Of 4

Swing Motor - Part 2 Of 3

Swing Motor (For Swing Parking Brake) - Part 1 Of 4

Switch Box (For Automatic Engine Speed Control And Swing Parking Brake) - Part 5 Of 6

Switch Box (For Automatic Engine Speed Control And Swing Parking Brake) - Part 4 Of 6

Switch Box (For Automatic Engine Speed Control And Swing Parking Brake) - Part 1 Of 6

Switch Box (For Automatic Engine Speed Control And Swing Parking Brake) - Part 6 Of 6

Switch Box (For Automatic Engine Speed Control And Swing Parking Brake) - Part 2 Of 6

Switch Box (For Automatic Engine Speed Control And Swing Parking Brake) - Part 3 Of 6

Switch Box (Body) - Part 3b Of 3

Switch Box (Body)--Part 3a Of 3

Switch Box (Panel)--Part 1a Of 3

Switch Box (Panel)--Part 1 Of 3

Switch Box (Body)--Part 3 Of 3

Switch Box (Meter Unit)--Part 2 Of 3

Track 17-3/4" (450 Mm) Flat Shoe

Track 17-3/4" (450 Mm) Triple Grouser Shoe

Track 23-5/8" (600 Mm) Triangle Shoe

Track 23-5/8" (600 Mm) Triple Grouser Shoe

Track Roller

Travel Drive - Part 5 Of 7

Travel Drive (For Blade) - Part 4 Of 5

Travel Drive (For Blade) - Part 1 Of 5

Travel Drive - Part 7 Of 7

Travel Drive (For Blade) - Part 5 Of 5

Travel Drive - Part 2 Of 7

Travel Drive - Part 3 Of 7

Travel Drive - Part 4 Of 7

Travel Drive (For Blade) - Part 3 Of 5

Travel Drive - Part 6 Of 7

Travel Drive - Part 1 Of 7

Travel Drive (For Blade) - Part 2 Of 5

Travel Drive And Sprocket

Travel Drive And Sprocket (For Blade)

Travel Lines - Part 1 Of 2

Travel Lines - Part 2 Of 2

Travel Motor Lines

Traveling Control (3bg1-09142) - Part 1 Of 4

Traveling Control (3bg1-09142) - Part 4 Of 4

Traveling Control (3bg09143-) - Part 5 Of 5

Traveling Control (3bg1-09142) - Part 3 Of 4

Traveling Control (3bg09143-) - Part 2 Of 5

Traveling Control (3bg09143-) - Part 3 Of 5

Traveling Control (3bg09143-) - Part 1 Of 5

Traveling Control (3bg09143-) - Part 4 Of 5

Traveling Control (3bg1-09142) - Part 2 Of 4

Upper Structure Lines (For Blade) - Part 1 Of 3

Upper Structure Lines (For Breaker) - Part 2 Of 2

Upper Structure Lines (For Blade) - Part 2 Of 3

Upper Structure Lines (For Blade) - Part 3 Of 3

Upper Structure Lines (For Breaker) - Part 1 Of 2

Vandalism Guard

Wiper Motor

Wiring Harness (For Cold Weather) - Part 2 Of 2

Wiring Harness - Part 2 Of 2

Wiring Harness (For Cold Weather) - Part 1 Of 2

Wiring Harness - Part 1 Of 2

Working Control - Part 1 Of 2

Working Control - Part 2 Of 2

Working Control (For Automatic Engine Speed Control)

Yoke And Tension

E70 serial number reference

The PIN/serial plate on the E70 is a riveted metal tag on the machine frame, commonly on the cab structure or upper frame near the operator's station; on machines this age also check between or near the hydraulic arms and the boom base for a stamped or riveted plate. Read the first three characters as the serial number prefix (identifies model/build series), followed by the sequential unit number; this pre-2001 format does not use the full 17-character PIN convention seen on newer Cat machines.

Prefix	Identifies	Notes
3BG	Base E70 crawler excavator, standard undercarriage	Only confirmed prefix for the base E70 (not the later E70B, which uses its own separate prefix). Sequence range 3BG00001-UP. Introduced around 1987. Fitted with the Mitsubishi 4D31 naturally aspirated diesel, rated near 52 flywheel hp for this application; the later E70B moved to the 4D32 (~54 hp) under its own prefix - do not blend that engine data in here. Built during the era of Caterpillar's Japan joint venture with Mitsubishi for excavator design and manufacture. Optional off-set boom and an increased-hp travel build are documented options on this same base machine, not separate serial ranges.

Frequently asked questions

What engine does the Caterpillar E70 use?

The base E70 is powered by a Mitsubishi 4D31 diesel rated near 52 hp. The updated E70B carries a Mitsubishi 4D32, rated slightly higher near 54 hp. Confirm which engine is fitted using the machine's serial number prefix before ordering engine parts.

What is the operating weight of the Caterpillar E70?

The E70 runs about 6.5 tonnes (14,300 lb) in standard configuration. The E70B is slightly heavier at roughly 6.9 to 7.0 tonnes (15,260 lb). Actual weight varies by bucket, arm length, and cab configuration.

What replaced the Caterpillar E70?

Within its own family, the E70 was directly updated by the E70B, which carried the larger 4D32 engine on the same basic chassis. Caterpillar's later mini and compact excavator generations eventually took over this size class, though no single named model is documented as a direct one-for-one replacement for the E70/E70B line.

What E70 owners discuss

What engine does the Cat E70 excavator run, and are there quirks to watch for?

The base E70 is built around a Mitsubishi 4D31 diesel rated around 52 flywheel hp (38 kW). This is a different engine setup than the later E70B, which shows up with either a different Mitsubishi 4D32 or a Cat 3114 depending on build year - don't assume parts, tuning, or troubleshooting steps carry across the two badges. On the 4D31, controls are mechanically governed with little to no engine electronics, so driveability complaints usually trace back to fuel delivery - injection pump condition, fuel solenoid, or plugged filters - rather than a failed sensor. Confirm the actual engine under the hood against the engine tag before ordering major engine parts, since more than one generation has carried the E70 name. Have your dealer verify engine identity and condition on a pre-purchase or major-repair job.

Why would one side of the machine lose travel or bucket curl while the other side works fine?

The E70's hydraulic layout uses two pumps riding a shared swash plate assembly, so a total loss on one side while the other stays healthy points operators first at that side's control valve, a relief valve that's backed off or tampered with, or low pilot pressure at the joystick - not a dead pump, since a shared swash plate normally keeps both sides live together. A loose or easy-moving joystick on the dead side is a classic sign of lost pilot pressure rather than a mechanical jam. Rule out solenoid wiring damage at the affected valve bank (corrosion or rodent chew is common on machines this age) before tearing into the pump itself. Have your dealer verify relief valve settings and pilot pressure before condemning a pump.

What causes weak or uneven track travel on the E70?

A frequent cause is seal wear at the center rotary joint (the hydraulic swivel that carries travel oil from the upper structure down to the tracks) - when those seals leak internally, one or both tracks lose drive pressure and travel feels weak or pulls to one side. Worn final drive components and uneven track tension can produce a similar drift complaint, so both the swivel and the final drives are worth checking before assuming a pump problem. Have your dealer verify swivel seal condition and travel circuit pressure if travel feels soft or uneven.

What undercarriage and wear items show up most on this machine?

Top rollers are a known wear point and can seize up entirely, requiring replacement rather than just cleaning. General track sag and pin-bushing wear track with hours and with how much the machine has worked on slopes or at full reach. None of this is unusual for a machine of this size and era - it is ordinary wear-item maintenance, not a design fault.

Are there notable electrical or sensor problems on the E70?

This generation predates electronic engine and hydraulic controls, so there is no fault-code network to chase. Most electrical complaints are basic: an aging ignition switch, deteriorating wiring insulation, and control solenoids that stick or short from corrosion or rodent damage inside the harness runs. If a whole bank of functions drops out together, check that valve bank's solenoid wiring before assuming a bigger hydraulic failure.

What should I check when buying a used Cat E70?

Confirm which engine is actually installed against the engine tag, since the E70 name spans more than one engine setup over its production run and that affects what parts fit. Run every function on both sides at once to catch a one-side-weak travel or curl symptom, which usually means a relief valve or the center rotary joint rather than a dead pump. Check the top rollers for stiffness or seizure, look for weeping at the center swivel, and ask for hour meter and service history - these machines often sit between owners and need a full service pass before returning to work. Have your dealer run a hydraulic pressure check and inspect pump condition as part of any pre-purchase inspection.

How does the E70 feel to operate compared to newer excavators, and is that normal?

Owners moving up from smaller mini excavators value the added reach and pulling power for working steeper or rougher ground, and generally consider the machine dependable once it is running right. The tradeoff is a slow, mechanical-lever hydraulic feel - often described as deliberate or clunky next to modern pilot-joystick machines. That character is a function of the machine's control design, not a sign of a problem.

Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.

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