How to predict failures
MODERN Land Rovers have far more inherent reliability than the old Series, Defender and other beamaxled models, though these, too, are becoming more reliable. Old Land Rovers are no longer expected to continue running on shoe-string maintenance budgets, they’re no longer abused and no longer modified with home-made gadgetry. They’ve become more appreciated because we know that Land Rover will never make anything like them again. We use and maintain our trucks properly for the simple reason that if we don’t, we’ll lose them.
Although fewer parts are failing, we still need to be vigilant in looking for potential future failures, and the best time to do that is during services and when repairs are carried out. The repair of a failed part should never be a simple matter of replacement. It’s essential to ask why the part failed, and to do whatever is needed to ensure the replacement part won’t fail prematurely in the same way.
Most components reach the end of their life through natural wear or ageing. But if, for example, an oil seal fails, it’s important to learn why it has failed and then fix the
cause before fitting the new seal. The seal might have hardened through age, but it’s also likely to have been distorted by wear in an adjacent bearing that has allowed the shaft to move radially inside the seal, distorting the seal’s lip and letting oil run out. In that case, the bearing needs to be replaced too, otherwise the loose shaft will damage the new seal. This commonly happens with differential pinion seals, wheel bearings and transfer box output bearings. With the latter, the oil seal often wears a groove in the shaft, meaning the shaft also needs to be replaced.
Gasket leaks are likely to be caused by loose fixing bolts, metal distortion or overpressure of the contained fluid. Before renewing the gasket we need to check the tightening torque of the bolts and whether they need locking devices, whether the flange has distorted from overheating and, if so, what has caused the overheat. Maybe the wrong gearbox oil has been used, or the transmission or axle breathers are blocked.
Investigating in this way increases our understanding of the vehicle’s systems, keeping us aware of the conditions components are subjected to, so we’re better placed to maintain them accordingly. By thinking in this way we learn to predict failures. It’s a skill we can all develop during routine servicing and repair work. The payback is a reliable Land Rover.