Filter Manufacturers Council – General Information

General Information

06/27/06

Hydraulic System Winterizing


Closer tolerances, higher operating pressures and increasing sophistication mean that today’s hydraulic systems demand more maintenance attention – and these demands increase as winter approaches.

Here are some basic checkpoints to help you get ready for efficient cold-weather operation.
First, take time to search out those areas where lower temperatures create greater stress. With the system operating, check all hoses and fittings and replace those that show signs of leakage and wear. If the system is often short of fluid, hold a piece of cardboard near where you suspect a leak. Remember, hydraulic fluid under pressure is dangerous, so use care and wear eye protection while doing this.

Searching out these potential trouble spots is important for several reasons: hoses which may have worked fine during the summer can rupture under the higher pressures caused by winter starting; pinched or dented lines can cause oil foaming, overheating and loss of power; and air leaks can cause fluid oxidation and form harmful gum and sludge.

Next, clean and flush the hydraulic reservoir and make sure you refill with hydraulic fluid that matches the manufacturer’s recommendation for cold-weather use. NEVER mix different brands of hydraulic fluid, unless their compatibility can be guaranteed.

At the same time, change all system filters. A partially-clogged filter, which operates properly in the summer can be forced into by-pass mode by the pressures created in cold-weather starting. This should be avoided because routing unfiltered fluid directly into the system mean extra wear on pumps and valves.

If you are using filters with cellulose media, consider changing to compatible models with synthetic media, such as Baldwin’s MPG. Although cellulose media may be equally efficient in the application, the extra cost of a synthetic media filters is often justified by its lower restriction. This is important for winter starts and warm-ups because it means there is less pressure buildup ahead of the filter, less potential for going into by-pass mode and less stress on the overall system.

Also, if there is a breather filter on the hydraulic reservoir, make sure you change it too. The breather is frequently overlooked, and if it is not doing it job, there can be harmful condensation as temperatures drop.

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