I would like to install new(repro)side dash vents in my 70,once you get the units out from the inside of the dash how do you get them open to install the vents?

The new units are all one piece; vents and housing. I bought a set for my 72 from Ground Up!

I dont want to buy the complete units,I want to find out how to install just the vents.

Using a dremel tool cut the welds that hold the palstic housing together. When they are all removed, the housing will seperate into two halves.
I ran the parts through the dish washer to clean them.
Put the assembly back together with some minute epoxy or model glue.
I reused the existing felt washers because the ones that came with the repos were thinner and the vent was loose.

Are you wanting to replace the vents because they will not hold position or because they have broken loose and are no longer connected? If they just won't hold their position, one trick I've used in the past is to buy velcro strips from the hardware store (black). Use only one side and cut a thin strip, it has adhesive that will secure itself to the side of the vent body, allowing the vent blades to have friction against the side of the body, thus holding them in any position you put them in. Is this shade tree or what?

I have a problem with my vents, when I try to adjust them vertically, usually only one little blade moves. Is there anyway to fix that? Sorry for the hijack but I was considering buying new ones until I read this thread.

Thanks for the reply,Dan,thats the info I was looking for.The chrome is pretty much gone on mine and one of the slats has fallen apart.Didnt want to spend the extra bucks for the whole units.