Hi, another Richard here, as John noted, I recently posted a lengthy description of my replacement of the exact hydraulic ram you are having problems with. If you are a patient wrencher, you can do it, if you allow frustration to make you throw things, or are old like me, and bending over on your knees for a couple of hours at a time is a near impossibility in itself, whip out the wallet, and look for an authorized HWH repair facility near you. I live in western Washington, and my options were either San Diego or Texas for closeness. You can take it to HWH in Iowa, they will affect a repair, and I've heard they are quick and reasonable.
A question I want to ask, is there a reason the seals are bad, besides wear? By the way, if it is leaking into your electrical cabinet outside, it is the seal. I had two symptoms, no apparent leakage when extending the slide, evidenced by the tub I put in the cabinet to catch hydraulic fluid, lots of leaking when retracting..as the severity if the leakage increased, the slide would go all the way in as it should, but creep back out an inch or so while heading down the highway.
I attribute the seal failure to excessive heat from a nearly catastrophic exhaust leak at the 90 degree turn after the turbo, right onto the area that houses that slide out ram. Any unusual heat or smell in the bedroom after driving all day?