Keeping your weight machine lubricated is very important, as it can add years of life to it. You can purchase the lubrication that you need from any major sporting equipment store, or even at the supermarket. Sometimes, weight machine manufacturers have their own brand of lubricant, so try to use that if possible, for optimal effect. If you have never lubricated parts of a moving machine, contact a professional to walk you through the steps on your first try.
Read through the user manual to see what type of lubricant you can use on your weight machine. The manual will also tell you where exactly the lubrication points are.
Clean off any previously applied lubrication from the weight machine using a damp cloth.
Apply the new lubrication on a clean cloth and wipe it onto the joints and movable areas of the weight machine.
Coat both sides of the area to prevent metal rubbing against metal.
Check the weight stack to see if it is sticking. If it is, use a wet silicon spray to lubricate the guide rods, which are the two bars on which the weights slide up and down.
Use a wrench to tighten or loosen any nuts or bolts during the lubrication process, but be sure not to over tighten anything. This might lead to the cables that are attached to the weight stack to become too tight, which will cause difficulties while you try to raise the weights during your workout session.