hydraulic problems - help

[R420]

I bought a 420 with what I believe is a Henry loader 6 weeks ago and everything with the loader worked fine initially. Then I went to use it a week ago when the temperature was below zero. Both bucket functions work fine and the loader down pressure lifts the front of the machine off the ground but there is no up pressure. I thought maybe there was some ice in a line but it's above freezing today and still nothing. There are two cylindrical covers on the back of the valve body that are held on with small cap screws. Both covers are about 2 inches in diameter, one is 2 inches long, the other is 4 inches long. Each of these covers have a small hole in the end. A small amount of hydraulic fluid seeps out of one of the holes when I try to raise the loader. Any ideas would be appreciated.

[NNAATZ]

i still think there is a frozen pak in the cylinders, sitting for aday in non freezing temp wont thaw them, think of how long it takes to thaw a pail of water. try letting run till it's warm then easly run the bucket an loader to cycle the warm oil into the cylinders. or use one of them magnetic block heaters on the tank an cylinders but you would be inviting more moisture