Tyler Office

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Jacksonville: (903) 586-8999

Jacksonville: (903) 586-8999

303.5E Cat Mini Excavator

303.5E Caterpillar Mini Excavator

303.5E Cat Mini Excavator

The Cat 303.5E CR delivers high performance in a compact radius design to help you work in the tightest applications.


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Comfortable Working Environment

Spacious and comfortable operator station with excellent visibility and legroom keeps the operator comfortable and reduces fatigue. Standard features include:

  • Reclining suspension seat with adjustable wrist rests.
  • Pilot operated controls on all services including travel levers and dozer functions.
  • Two post canopy design for better visibility to the work area.
  • A pattern control changer (not available in all regions) is accessible from the cab to switch between excavator and backhoe style controls.
  • Ample storage space under the seat that can be locked for added security.

Optional Enclosed Cab

For even greater operator comfort, an enclosed cab is available as an option and features:

  • Enclosed cab with heat and optional air conditioning to keep you comfortable in a wide range of conditions.
  • Radio ready with speakers and easy radio installation.
  • Removable lower front window and sliding windows for excellent overall visibility.
  • Gas assisted front window slides up with minimal effort.
  • Sliding door system offers good access and maintains the machine’s compact dimensions, reducing the risk of damage.

Joystick Controls

The boom swing and auxiliary hydraulic functions are located at your fingertips providing smooth, easy operation. These joystick mounted controls deliver more productivity through precise movement of the boom swing and auxiliary functions. They also eliminate foot pedals and free up the floor for more room for the operator’s feet. 100% pilot controls provide consistent flow and pressure throughout the life of the machine. This also allows all controls to be locked out while starting the machine and when the safety lockout bar is in the up position.

COMPASS Display Panel

Unlock the new features and experience the value of the exclusive COMPASS control panel on the new E series Excavators. The brand new Complete Operation, Maintenance, Performance and Security System on the Caterpillar E series mini hydraulic excavators was specifically designed by Caterpillar for compact excavators. It adds several new features to the machines increasing the amount of customer value:

  • A Standard Anti-theft Security System
  • Adjustable Work Tool Auxiliary Flow Control
  • Continuous Flow
  • Economy Mode – save up to 20% fuel while maintaining high productivity with the push of a button.


All four E-Series models feature increased stability, while maintaining the compact radius design. This increased stability leads to more productivity and versatility through the use of heavier work tools and the optional long stick.

Fast, Powerful Digging with Load Sensing Hydraulics

High digging forces and fast cycle times deliver the productivity that your job demands. Load sensing hydraulics optimize flow for smooth, powerful performance and increased fuel efficiency.


High performance power train provides optimized engine horsepower and strong performance. Engine meets U.S. EPA Tier 4 Interim and EU Stage IIIA emissions requirements. Automatic engine idle automatically lowers engine revolutions when not in use to conserve fuel and lower environmental noise and emissions. The E-Series models feature an engine kill switch conveniently located in the cab and accessible from ground level.

Automatic Two Speed

With the standard automatic two speed feature, the machine will automatically balance high speed and torque travel requirements based on the conditions to give the operator the optimum speed and control. The machine can be put in low gear if slower travel is desired while in tight conditions.

200 Degree Bucket Rotation

Industry leading bucket rotation of over 200 degrees provides greater material retention during truck loading. It also allows for easier vertical wall digging without having to reposition the machine.


Zero Tail Swing

The 303.5E CR features a zero tail swing design. On these models, the radius of the upper body stays entirely within the width of the undercarriage.



The E-Series is available with a mechanical pin-grabber or a hydraulic pin-grabber quick coupler option. The coupler design uses a wedge to keep the tool secure to the coupler, reducing wear and maintaining a tight fit through the life of the coupler. The hydraulic coupler allows the operator to change tools without leaving the comfort of the cab.

Wide Range of Work Tools

A wide range of Cat Work Tools have been designed specifically for the Cat Mini Hydraulic Excavators to maximize machine performance. Available work tools include:

  • Buckets (heavy duty and heavy duty capacity)
  • Tilting, Ditch Cleaning Buckets
  • Hydraulic Hammers
  • Augers
  • Thumbs (not available in all regions)
  • Vibratory Compactors
  • Quick Coupler

Standard Thumb Ready Sticks (optional in Europe)

Machines come standard with stick mounted brackets, ready to fit a hydraulic thumb for even greater machine versatility. A factory installed bracket and relief valve make hydraulic thumb installation simple and cost-effective.

Standard Auxiliary Lines and Accumulator

One-way and two-way auxiliary lines (combined function), including quick connections, are fitted as standard equipment so the machine comes ready to work. A standard accumulator allows for auxiliary pressure to be released, making connecting and disconnecting work tools safer and easier.


Simple Dozer Control with Float Function

The dozer function is pilot controlled from inside the cab, providing smooth, proportional operation. The standard float function is enabled by pushing the lever fully forward into the detent position. Cleanup and backfilling is easier since the operator does not have to adjust the blade height during travel.

Excellent Blade Visibility

Visibility to the blade is excellent in any position, allowing the blade to be positioned behind the operator and away from the front linkage for better access when back dragging and finishing in tight areas.

Angle Blade Option

Increase machine versatility with the Cat angle dozer blade. Built for strength and durability, the hydraulic angle blade features a hardened steel wear edge and good protection to cylinders and hydraulic lines. The angle blade can be positioned straight ahead or angled up to 25 degrees to the left or right. This reduces the number of times required to back up and reposition when backfilling so you can finish the job faster. All functions of the blade are controlled with one joystick using a proportional roller switch for the angle function.


Rubber Track

The standard rubber track lets you work on multiple surfaces such as grass, pavement or stone without damaging the surface or machine.

Steel Track Option

Optional steel track is available for harsh conditions such as demolition. The extra weight of the steel tracks generally provides better stability when digging over the side of the machine.

Rubber Pads

Optional rubber pads can be attached to the steel track to prevent damage to paved surfaces and minimize noise and vibration during travel with the steel track system. This option provides the maximum overall stability.


Easy Service

Convenient service features make maintenance easy, reducing your downtime:

  • Lifting side hood allows access to air filter, main implement valve, 1-way/2-way auxiliary flow selector, accumulator, fuel filter and hydraulic tank. This eliminates the need to lift the cab when maintaining and servicing the machine.
  • Swing out rear door provides access to major components and service points including engine oil check and fill, vertically mounted engine oil filter, starter motor and alternator.
  • Easy access to the radiator and oil cooler results in simplified cleaning and reduced maintenance times.
  • SOSSM oil sampling valve allows easy sampling of the hydraulic fluid for preventative maintenance.
  • 500 hour engine oil and filter change period reduces operating costs and machine downtime.

Superior Dealer Services

Your Cat dealer is ready to assist you with your purchase decision and everything after.

  • Financing packages are flexible to meet your needs.
  • Unmatched parts availability keeps you working.
  • Make comparisons of machines, with estimates of component life, preventative maintenance and cost of production.
  • Your Cat dealer can evaluate the cost to repair, rebuild and replace your machine.
  • For more information on Cat products, dealer services and industry solutions, visit www.cat.com.


Engine Model Cat® C1.8
Net Power 31.6 HP
Gross Power 33.3 HP


Operating Weight 7734.0 lb
Operating Weight – With Cab 8139.0 lb


Maximum Digging Depth – Standard Stick 9.6 ft
Maximum Reach – Ground Level – Standard Stick 16.7 ft
Height – Over Cab 8.2 ft
Maximum Horizontal Reach – Standard Stick 17.1 ft
Shipping Length 15.5 ft
Maximum Vertical Dig Depth – Long Stick 8.2 ft
Maximum Dump Height – Long Stick 11.9 ft
Maximum Horizontal Reach – Long Stick 17.8 ft
Transport Width 5.8 ft
Maximum Dump Height – Standard Stick 11.5 ft
Maximum Cutting Height – Long Stick 16.5 ft
Track Shoe Width 1.0 ft
Maximum Cutting Height – Standard Stick 16.2 ft
Maximum Vertical Dig Depth – Standard Stick 7.7 ft
Shipping Height 8.2 ft


Bore 3.4 in
Stroke 4.0 in
Displacement 110.0 in³


Travel Speed – High 2.8 mile/h
Maximum Traction Force – Low Speed 6969.0 lb
Maximum Traction Force – High Speed 3799.0 lb
Travel Speed – Low 1.6 mile/h


Operating Pressure – Equipment 3553.0 psi
Digging Force – Stick – Standard 4249.0 lb
Digging Force – Stick – Long 3799.0 lb
Digging Force – Bucket 7419.0 lb
Operating Pressure – Travel 3553.0 psi
Operating Pressure – Swing 2625.0 psi
Auxiliary Circuit – Primary 15.9 gal/min
Auxiliary Circuit – Secondary 7.1 gal/min


Machine Swing Speed 9.0 r/min
Boom Swing – Left – Without Stop 80.0 °
Boom Swing – Left – With Stop 55.0 °
Boom Swing – Right 50.0 °


Width 70.0 in
Height 12.8 in
Dig Depth 18.5 in
Lift Height 15.7 in


Cooling System 1.5 gal (US)
Engine Oil 1.8 gal (US)
Hydraulic Tank 11.2 gal (US)
Fuel Tank 12.2 gal (US)
Hydraulic System Hydraulic System


MSC Spec Date 3/06