‘56 Buick: Help with resealing firewall fresh air intake flaps

[Bgs]

Hi all, the rubber seals on the cabin fresh air intake flaps in the 2x vents along the firewall are brittle and deteriorating. I would like to replace them. Anyone know of a good source of either a) flaps pre-assembled with fresh rubber, or b) a source for replacement rubber seals?

 

If I go route ‘B’ it appears I will need to split the metal-rubber-metal flapper sandwich apart. It has at least 2x rivets I would need to drill through. Are the other 8x circles spot welds…? Has anyone else split these apart before? I’d greatly appreciate any insights before I start drilling. 
 

If I cut my own seals, should I use EPDM or Neoprene or something else?

 

thanks!

 

 

 

 

[buickbrothers]

I did something different if it helps you or provides an alternative. I had a similar problem, and I took the less labor-intensive path of separating the plates as well. I found a very thick grey felt at a fabric store that was equivalent to the rubber thickness - like a Hobby Lobby. I trimmed the depleted rubber down to about 1/8 and bonded the felt to the remaining rubber. I used a wider piece of felt so I could then trim it for just the right fit/seal. The felt actually sealed better and doesn't deteriorate like the rubber does. Plus, it's very inexpensive. Hope that helps.   

[Bgs]

@buickbrothers, thanks for the suggestion. Unfortunately the rubber on mine is too brittle to bond to. It disintegrates when I touch it. 
 

I decided to move forward and drill out the spot welds to separate the plates.  After zinc plating, I’ll cut out a some EPDM or Neoprene and use rivets on the 2x original holes and 8x spot weld location holes. Note: a few of the spot welds were weak and i could separate by hand without drilling, but I ended up drilling anyways as I will use rivets to squeeze the sandwich back together. 
 

Here are some mid progress photos showing what the rubber between the plates looks like. 

[NTX5467]

Perhaps some "masticated rubber sheet", which is the type of rubber the upper control arm water shields are made from, might work better than neoprene?  To me the reason is longer-term durability and possible stiffness.

 

Just some thoughts,

NTX5467

[Bgs]

Got the parts back from the zinc plater and reassembled with rivets. Ended up using an epdm rubber sheet. It ended up being about twice as thick as the original and I’m crossing my fingers it will fit. (Body shell is off at the fab shop so I can’t test fit).

[Beemon]

It looks like the original had 1/2 diameter holes for the stamped portion, but you only drilled out the holes through the rubber. Did you have any issues with it squishing or clamping completely? Need to do this soon. 

[Bgs]

Although the stampings were 1/2”, the actual spot welds were smaller diameter. The holes I drilled were about the same size as the spot welds. This means the rivets could clamp in a similar manner as the original spot welds. 

[Beemon]

Sorry I mean these holes:

[Bgs]

in hindsight, I maybe could have sharpened the end of a tube and used a mallet to cut those out but It didn’t seem to cause a problem. The rubber was pretty squishy. I think those were maybe oversized originally such that it wouldn’t interfere with the spot welds.