Hi-Lo repair in the Portland, OR, area...
Chris,
Don't know if this will help, but the last Hi-Lo dealer in your area was: Camper Outlet, 9620 SW Tualatin-Sherwood Road, in Tualatin. Their phone number is: 800-213-6799.
I actually visited this place in 2009. Frankly, they were sour on Hi-Lo trailers, something about of Hi-Lo corporate policies on the quantity of inventory they had to maintain and the fact that Hi-Lo wanted them to outright buy the trailers for resale (apparently different from the majority of trailer manufacturers, who will work out dealer loans). All we heard from the owner were complaints.
Never-the-less, they may still have technical experience, and expertise to handle your repair. Or be able to refer you to whoever was doing their warranty work.
Now, having said all this, Hi-Lo trailers for the most part, are much like every other trailer made. The lift system is the biggest unique component. My suggestion is to ask around and find out where your camping friends take their rigs for repair. Referrals are golden when it comes to honest and good trailer repair work. My bet is you'll soon find an outfit who can handle just about all of your Hi-Lo repair and maitenance needs. Went through the same process here in SW Idaho.
Good luck,
Jim