[farmike]

just about ready to do the maxxair 7500 deluxe install. Does anyone remember who had the pilot holes drilled for the roof screws and what size bit they used?

 

[keeponvaning]

It's never been an issue for me. I always just choose a smaller size drill bit than the screws, not to mention, you probably want to put a wood frame underneath it for more strength anyway and you will need longer screws. I would suggest just getting stainless nuts and machine screws to do the job and throw the others away.

 

[Andrew Crane]

Just size down your bit from the screws, I think it was an 1/8" bit that I used. The screws that come with the vent are already stainless so used the supplied ones. I have 2 fans, the back one I didnt screw into a wood frame and it has held on for almost a year. The front fan I installed a few months later and adjusted my install technique.

Both fans have butyl tape as the gasket and Eternabond as the exterior sealant. I highly recommend the Eternabond, super easy to install, looks good and holds up well; compared to dicor lap seal. Just my 2 cents on that one.

You will want to build up the butyl tape to be taller than the ribs of the roof. And if using Eternabond tape, I recommend getting the 4" wide stuff. The 3" I used was a tad too narrow once it contorted around the dips in the ribbing, so i had to double up the 3" tape.

Good luck, super easy to do and makes a difference in temp during the summer time.

 

[mikemarmar]

I think I also used an 1/8" bit. I then drilled the screws in part way and removed them before putting in the fan to tap the holes. Made it nice and smooth once the fan was in.

It seems plenty strong without a wood frame inside the van.

 

[farmike]

I think I also used an 1/8" bit. I then drilled the screws in part way and removed them before putting in the fan to tap the holes. Made it nice and smooth once the fan was in.

It seems plenty strong without a wood frame inside the van.

thanks; Ive already got the wood surround in ; took two tries which is acceptable for me.