Dixon Hydro repair/replace

[tandem160]

Hello all, I've have a Dixon 2001 4515b hydro that I'm going to try and fix. My parts are coming in three to five days. How easy/hard will it be to remove the left side hydro from the mower? I know nothing about hydros even though I have two hydro mowers, I figure I'll learn soon enough but, I'm still wondering. It looks to all self-contained with only two valves for control on the front. Any help would be appreciated

 

[tandem160]

Okay not hard to remove hydro.. I got the hydro opened up letting fluid drainout of it and know I'm wondering what should I use as a sealant to lock it all back up when I'm done?