JCB 6T-2 (6 Tonne) Dumper

The JCB 6T-2 Dumper is a robust and efficient machine designed for heavy-duty material handling in construction and industrial settings. Despite its durability and performance, regular use can lead to common mechanical, hydraulic, and electrical issues that may disrupt operations.

This knowledge base provides clear and concise solutions to the most frequent problems encountered with the JCB 6T-2 Dumper. It also includes essential maintenance tips to help operators and technicians keep the machine running reliably, minimize downtime, and maximize productivity.


1. Engine Starting Issues

Problem:

  • The engine fails to start, struggles to turn over, or starts intermittently.
  • Battery issues, fuel system faults, or electrical problems.

Solutions:

  • Check the battery voltage and terminals; clean corrosion and tighten connections. Replace the battery if weak or faulty.
  • Inspect fuel filters, fuel lines, and injectors for blockages or leaks. Replace clogged filters.
  • Ensure the starter motor and glow plugs (for diesel engines) are functioning correctly. Replace faulty components.

2. Hydraulic System Problems

Problem:

  • Slow or unresponsive hydraulic tipping or steering.
  • Hydraulic fluid leaks or unusual noises (air in the system).

Solutions:

  • Check hydraulic oil levels and top up with the correct fluid.
  • Inspect hoses, seals, and connectors for leaks or damage; replace any worn components.
  • Bleed the hydraulic system to remove air pockets.
  • Clean or replace the hydraulic filters.

3. Transmission Issues

Problem:

  • Difficulty shifting gears or lack of drive power.
  • Transmission overheating or noisy operation.

Solutions:

  • Check and top up transmission fluid to the correct level. Replace contaminated or old fluid.
  • Inspect the clutch (for manual models) and gear linkage for wear or misalignment. Adjust or replace as needed.
  • Ensure the cooling system for the transmission is functioning properly to prevent overheating.

4. Brake System Failures

Problem:

  • Weak, spongy, or unresponsive brakes.
  • Brake fluid leaks or worn brake components.

Solutions:

  • Check brake fluid levels and refill with the recommended fluid.
  • Inspect brake lines, cylinders, and seals for leaks or damage; repair or replace as necessary.
  • Replace worn brake pads, discs, or drums.
  • Bleed the braking system to eliminate air from the lines.

5. Electrical Faults

Problem:

  • Lights, indicators, or dashboard display fail to work.
  • Battery drains quickly or fuses blow frequently.

Solutions:

  • Check the fuse box for blown fuses and replace with the correct rating.
  • Inspect wiring for frayed or damaged insulation and repair as needed.
  • Test the alternator to ensure it’s charging the battery correctly. Replace faulty components.

6. Overheating Engine

Problem:

  • Engine temperature rises excessively, causing shutdown or power loss.
  • Coolant leaks, radiator blockages, or faulty water pump.

Solutions:

  • Check coolant levels and top up as required. Use the correct coolant mix.
  • Inspect the radiator for blockages; clean debris and repair damage.
  • Test the water pump and thermostat; replace if faulty.
  • Ensure the engine cooling fan and belts are functioning properly.

7. Tyre Wear and Damage

Problem:

  • Uneven tyre wear or frequent punctures.
  • Reduced traction and stability.

Solutions:

  • Regularly check and maintain tyre pressure to manufacturer specifications.
  • Inspect tyres for damage, wear, or punctures and replace if necessary.
  • Avoid overloading or operating on excessively rough surfaces.

8. Excessive Noise or Vibrations

Problem:

  • Loud knocking noises or vibrations during operation.
  • Loose components, worn bearings, or engine issues.

Solutions:

  • Inspect engine mounts, bolts, and bushings for looseness or wear. Tighten or replace as required.
  • Check wheel bearings, driveshafts, and universal joints for wear and damage.
  • Ensure regular lubrication of all moving parts to reduce friction and wear.

9. Exhaust Smoke

Problem:

  • Black smoke: Excessive fuel burning.
  • Blue smoke: Oil burning.
  • White smoke: Coolant burning.

Solutions:

  • Black smoke: Check air filters, fuel injectors, and turbocharger for faults.
  • Blue smoke: Inspect piston rings, valve seals, or turbo for oil leaks.
  • White smoke: Check for coolant leaks and inspect the head gasket or radiator for damage.

10. AdBlue System Issues (If Applicable)

Problem:

  • AdBlue warning light illuminates.
  • Poor engine performance or failure to regenerate exhaust systems.

Solutions:

  • Ensure the AdBlue tank is filled with clean, high-quality AdBlue fluid.
  • Inspect the AdBlue injector and lines for blockages or leaks; clean or replace as needed.
  • Reset the system using diagnostic tools if faults persist.

General Maintenance Tips:

  • Perform daily pre-operation checks: oil, fuel, coolant levels, tyres, and visible leaks.
  • Regularly grease moving parts like joints, tipping mechanisms, and steering components.
  • Follow JCB’s recommended service intervals for oil changes, filter replacements, and system inspections.

By addressing these common problems promptly and maintaining the JCB 6T-2 Dumper regularly, you can ensure optimal performance, extend its lifespan, and reduce downtime on site. If you still need help you can contact a experienced professional – That’s Us!

Spares & parts bibliography

For all spares and parts we recommend our sister company – HTS Spares

Main Parts Page: JCB Dumper Spares | HTS specialise in supplying dumper parts and spares for a variety of JCB dumpers

The guys at HTS Plant Sales are great. They obviously have a wealth of experience in compact equipment which makes dealing with them very easy.
Construction Company, Leeds