hitachi ex60-3/ john deere 190E drive motor hydraulic question.

Recently purchased a 1998 john deere 190e with 3500hrs which had one drive motor leaking. Still tracked and moved fine but was leaking from the cone seal at behind the sprocket. I have done a lot of looking to try and find any information about the drive motor which I found that my machine is basically a hitachi ex 60-2 or 3 and from the looks has the same drive motor as mine which is also a hitachi drive. I pulled the final drive off and was going to install new seals but don't want the same thing to happen again and possibly blow the seals right away so wanted to make sure I have a problem corrected if there is one. I do have hydraulic fluid in the gear side of the final drive so the shaft seal was blown as well. My question is I have been reading that these drives have a built in parking brake with seals that leak and blow out the other seals on the drive but looking at the part brake down on http://ift.tt/1KZMIi1 am am not seeing what appears to be brake o ring seals. I have all new hydraulic filters and am going to flush system and am going to check by blowing out the smaller return line from the final drive to make sure its not clogged and actually replace that line seeing as it had a few small little splits up near where it T's in at the swivel joint. The one to the other drive motor is new but doesn't look like the drive was touched so doesn't appear the motor had an issue just the hose had a leak. Is anyone familiar with these machines? Is brake on these done by pressurizing both forward and reverse hoses when not controlled to track forward or backwards on that side? I had my hoses sealed up to prevent dirt entering with a thick plastic bag and zip ties and started the machine after repairing the exhaust leak I had on the flared manifold pip pipe up to muffler it pressurized both and popped the bag which I quickly turned off the machine. I just wanted to make sure that was normal before fixing the drive and hooking backup just to blow the seals again. Any help would be greatly appreciated.

hitachi ex60-3/ john deere 190E drive motor hydraulic question.