tcnmchu - We have a Rockwood Roo 17, and completed this mod this past Sunday evening. It was actually more straight forward than I first thought. You DO have to drop the fan out to access the backs of the bolts - It was useful to have a second set of hands available to do the inside work while you're on the roof if they can tear themselves away from their video games long enough.
(2007flagstaff is probably right that self tapping would hold it in place as well - but I stuck with the bolts that came with)
- Most important first step - Dryfit the MaxxAir cover and test the vent for height and square. Crank the vent open until it just touches the inside of the MaaxAir, then back it off slightly. Do this a few times until you're satisfied it is not too far back or forward.
- Inside the trailer, Remove the fan - not as hard as it sounds - stand under the fan, and note the 4 screws. Remove them, and put them aside. (Be sure your sink drain plug is in tight - you don't want to try to retrieve dropped screws from your grey tank).
- using the same screwdriver, remove the screw from the centre of the Crank wheel - it will loosen and you can remove the handle and put it aside. You will find another screw under that handle, remove it and put it aside. Your fan will now be loose, but held in by a bit of sticky material at one of the posts.
- Maneuver the edges of the fan until it drops down low enough that you can remove it. I was able to put a small screwdriver into the hole where it was binding and a bit of work at it, came right out. Wire length is ample to rest the edge of the assembly ontop of the mirror while you do your work, without disconnecting anything
- Back up on the roof, you can follow the video MaxxAir that Sgt. Schultz kindly provided (for the sake of clarity, I'll detail my steps as well)
- trace all 4 holes of the MaxxAir onto the generous bead of sealing material that Forest River puts around these vents
- remove the vent cover and set it aside - you'll see the 4 holes on each side that you traced.
- place one of the brackets over the trace marking - as close to the corners of your vent frame as reasonably possible is best
- Trace the hole onto the side of the vent frame while holding the bracket in place (have the vent partially cracked open so you can see where the drill bit will go when you get to that step
- Drill the 4 holes, slowly, and watching the inside of the vent during the process so you don't hit any wiring or brackets
(This is where your inside helper comes in handy).
- Put the large bolt in the bracket from the bottom - you can't do it later! (which will hold the vent cover), then place the bracket to the hole, and insert your bolt
- have your helper reach up and put on the lock washer and nut inside the vent housing
- Use your screwdriver to tighten from your side - your helper can hold the nut with a small adjustable wrench. (You'll be able to feel what's reasonable for tightness).
- Once your brackets are all mounted, place the vent cover over the bolts you previously inserted up through the brackets, place your lock washers and nuts, and tighten. (again, you will know what is reasonable for tightness).
- Now it's time to put your fan back in place, starting with the screw under the crank handle - then each of the others, and finally the crank handle itself.
- Open your vent, test your fan and you should be good to go, with no more wet floors when the vent is left open during an overnight rain-storm !
- One thing to note - do not expect the MaxxAir to sit flat against the bead of sealant or tight against the roof - an airspace under it keeps moisture from collecting
Hope this helps !