My heater core was wrapped in felt, or something like felt. A strip was placed between the sides and the heater box, and thin strips were placed in the holding brackets. These fabric pieces held the core in place, I guess. I don't think rubber buttons were ever used because the holes for them have paint in them, which would have been broken away had the rubber bits ever been installed. Anybody seen this? I have an idea I might put some thick felt in there...any experience out there?

Your right "something like felt". Be careful, it's asbestos. It's not friable, but when removing it, be careful. I usually keep a spray bottle of water around, and spray it down a bit.

All the sound deadening material that looks like that stuff is asbestos containing material.

Paul

I used sponge stuff I had here. looks like this. It is close to the stuff that was in my 68. I'd think felt would retain more moisture and rot.

Mine had a thin layer of plastic foam. I think I used polyethylene foam packing material
when I refurbed it. It was a sheet about 3/16" thick,

cool you guys. Yeah I agree the felt would be prone to rot...I like the stuff you both used, synthetic and made for eternity. I like the little round washers from the dvd stacks too. Thanks for the pictures, dinahmoe. I'm gonna re-use my old clunky volvo motor...it needed some brush work but seems okay now. I just hope to get some actual breeze out of the thing when I reassemble it...if that is possible. There was a mouse nest in among the flaps...brush problems...mud inside the core...general rust and decay and putrefaction and ossification.

Be sure your fan motor bearings are clean (I used lacquer thinner and q-tips)
and oiled with 3-in-1 or sewing machine oil. NOT ANY KIND OF PENETRATING OIL!!

Were you able to get the plastic fan off the end of the shaft? That has me stopped, for fear of breaking it.

Yes, I did get it off. I don't remember exactly how I did it.
If it has a spring clip around it you should see if you can get it off.
Since most plastics expand a lot more than metal, you might set it with the fan end
down in a container of water (Maybe 150° F or as hot as you can get your tap water)
for 15 or 20 minutes and that will make it looser on the shaft (probably less brittle also).
Don't put the motor in water!

don't see a clip of any kind, looks like a press-fit. I will give the hot water a try. Gently. Thanks!

I used a center punch on the center shaft hold the bottom motor and one hand on the fan. Did not take it all the way off but enough to oil the shaft and bearings