Taking the mystery out of repairing hydraulic rams
Jamie Casey analyses a farm machinery essential
Almost every piece of agricultural machinery around the farmyard is equipped with a hydraulic cylinder or ram.
Essentially, a hydraulic ram is used to convert oil flow into powered linear movement, in either one direction (single- acting ram), or two directions (double-acting ram). Rams provide the power to machinery that has allowed output to increase exponentially in the last 100 years.
For the purpose of this article, we will look at a double-acting ram. This is a ram that provides powered linear movement in two opposing directions, like the ram on a shear grab for example, which uses hydraulic power to both open and close the grab.
A double-acting hydraulic ram has two internal chambers, one for providing power in each direction.
There are a number of internal seals which prevent the oil from passing from one chamber to the other. When these seals fail, the oil moves between the chambers, causing unwanted linear movement in the ram.
This can often be observed on an attachment like a front-end loader. If the loader is left in a raised position for a period of time, it will slowly creep down. This is generally caused by oil escaping from one internal chamber to the other due to worn or damaged internal seals.
However, changing these seals is not a difficult task once you know a bit about the internal workings and follow the simple steps I go through here.
As with any hydraulically operated implement, safety comes first. Remember to never work under an unsupported load or object.