Landcruiser brakes fail in underground mine

The driver of a Toyota Landcruiser Ute was travelling down a decline in an underground mine. He applied the brake pedal which went straight to the floor with no apparent braking.

Incident

The driver of a Toyota Landcruiser Ute was travelling down a decline in an underground mine. He applied the brake pedal which went straight to the floor with no apparent braking.

Circumstances

By driving at a safe speed, changing down the gears, and hitting the tunnel wall, the vehicle was able to be bought to a halt. The vehicle was slightly damaged; no injury was sustained by the driver. 

Investigation

On removal of the right-hand rear brake drum, it was found that the bottom side of the brake shoe was twisted. The base where the brake shoe locates was also twisted at an angle. This misalignment caused the brake shoe to wear unevenly and the top side of the brake shoe to lose contact with the brake cylinder. This caused the piston to over-stroke and lose the rear brake fluid, and braking efficiency was diminished.

The brake drum was in good serviceable condition. The vehicle itself was around two years old, and subject to regular fortnightly maintenance checks. A similar degree of wear was found in several other Landcruiser vehicles used in the same kind of environment.

Guidance

During fortnightly maintenance checks, the brake drum housing should be removed so that the brakes can be inspected more thoroughly, as the existing hole for inspecting brake shoe wear doesn’t identify this issue. All utes used for underground mine transportation of equipment and workers should be inspected for similar issues.

image hazard alert brake piston

Ministry of Business Innovation and Employment Advice

Although the problem can be managed through increased maintenance, converting to a more appropriate braking system should be considered. Rear disc brakes are substantially more durable and easier to inspect for wear. Sealed Integrated Braking System (SBIS) have been trialed in similar environments with success.

Note - This material has been prepared using the best information available to the Ministry of Business Innovation and Employment Advice at the time of publication. Information may change over time and it may be necessary for you to obtain an update. This material is also only intended to provide general advice and does not constitute legal advice. You should make your own judgement about action you may need to take to ensure you have complied with your workplace health and safety obligations under the law.

Which industries/sectors or matters will this information be relevant to?

All sectors whose utes undergo similar heavy industrial use – Mining and extractives, quarrying, roading...