Toyota Landcruiser Rear Brake Upgrade Package

Toyota Landcruiser 78/79 Series Vehicles are used extensively throughout the country, and in particular, are favoured by mining operators, many in underground use where conditions are extreme. Whilst the basic vehicle is well respected by the industry, the rear disc brake arrangement has proven to be inadequate for the conditions, with the rear brake pads and hand brake both exhibiting accelerated wear way beyond the rest of the vehicle. In worst conditions, the rear brake linings will wear to the metal backing plates in a matter of weeks, resulting in total loss of rear brakes with accompanying work safety concerns. Handbrakes often fail to hold with days. Analysis of the Problem With this series of 78/79 series vehicles, Toyota moved to a rear disc brake design incorporating a drum type hand brake within the disc. There may have been reasons for this design, but it seems to have been a retrograde step when subjected to regular immersion in muddy and highly corrosive environments. There seem to have been several compromises needed to arrive at this design.

Cause of Rear Brake Problems 1. Combining a drum handbrake and a disc rotor and caliper within the confines of a 16-inch wheel necessitates a small brake caliper and small pad radial section, resulting in an undersized pad area. The standard design has a thin disc and a handbrake of small diameter and swept area relative to the weight of the vehicle. 2. The backing plate and handbrake arrangement allow mud and slurry to enter but not exit, causing abrasives to accumulate and rapidly destroy the handbrake, including its function as an emergency brake. 3. The small disc pad contact area is at odds with the affects of loading under abrasive conditions where rates of wear are parabolic for wear rate versus load. 4. The handbrake design is fiddly and complicated with many small parts that prove to be difficult to assemble correctly.

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