Axles, Braking, Workshop

Post Flooding Maintenance Tips

post flooding maintenance tips

If a heavy vehicle gets trapped in deep floodwater, a detailed and comprehensive maintenance program is required before it can be returned to service, here are some post flooding maintenance tips.

Anyone who owns trucks dreads the thought of their vehicles being swamped by floodwater, and with the recent deluges this country has received, and the continuing La Niña weather pattern promising to bring more of the same, the likelihood of this happening has been elevated considerably. 

As a general rule, vehicles shouldn’t be driven through water deeper than the centreline of the axles, but even then there are risks associated. For example, if a vehicle that has been driven and braked hard is driven straight into deep water the sudden cooling of brake drums can cause them to crack and the cooling of hubs and bearings can draw water in past the seals, even if they are undamaged. Therefore, even relatively shallow water crossings should not be made without first pausing for at least 30 minutes to allow these components to cool.

If the water level is above the top of the diff housing the likelihood of water entering through the breather is high. Hence the reason 4WD vehicles that do river crossings have gearbox and diff breather extension tubes.

The real problem with a vehicle being partially submerged by floodwater is the fine mud and sediment suspended in the water that settles inside the diffs and gearbox and if not removed can cause rapid wear of gears and bearings. 

Therefore, it is imperative that the oil and water are drained out as soon as possible. Then the axles and hubs are removed and the axle housing interior thoroughly steam cleaned to remove all traces of grit. 

After washing the bearings and re-oiling them the hubs and axles are reinstalled and the diffs and gearbox are filled to the filler plug levels with diesel fuel, which is actually a very light oil.

Then with the vehicle suitably supported on jack stands to elevate the drive wheels, run the engine with top gear selected for five to ten minutes. This will ensure the last traces of water and grit are washed away. 

Remove the drain plugs and allow the vehicle to sit overnight to ensure all the diesel fuel is fully drained out, then reinstall the plugs and fill the components with the recommended grade of oil. As a rule, using synthetic oil in these components provides superior lubrication because it doesn’t break down and lose its effectiveness over extended periods like mineral oil can.

Similarly, the steer axle wheel bearings will need to be removed and washed before being re-lubricated and reinstalled.

Generally speaking, unless the water level completely submerges the engine there is usually no avenue for water entry into it. Just to be sure, it’s a good plan to change the engine oil anyway.

After this, grease every universal joint and slip joint on the driveline, as well as the king pin and steering linkage grease nipples (if fitted) to purge any water that has sneaked in past the seals.

Finally, inspect the radiator, oil cooler, intercooler and air conditioning condenser cores and blow out any debris that may have lodged between the fins.

Following these simple practices should ensure a safe and trouble-free return to work for the vehicle, with minimal impact on the life expectancy of the various components.

post flooding maintenance tips

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