Tazza is right on the load checks, They are plugs on the loader valve that hold it until the oil builds up enough to lift, after supporting the loader (very important when working with hydraulics) you can take those plugs out and you will see a spring and a valve. What happens is that valve starts to wear into the plug/cap and creates a little ridge to it hangs up on there. The easiest way to fix it is to use emery cloth, or a sander attachment on a die grinder and smooth the inside of that cap/plug so there isn't a lip or ridge for the valve to hang up on