Finishing up my interior project. Now that I’ve installed new speakers and have the radio up and running again, the dash is ready to go back in.

Was thinking that the clips or edges of the dash contribute to the ubiquitous squeak that the dash has over bumpy roads. Curious if anyone has had success addressing this on a dash reinstallation?

 

If you figure that out, bottle it and sell it. You are talking about a vehicle built in the 1970's with design and materials that were available at the time, a vehicle who's intended lifespan was 5-7 years, and being built by Chevy---not Oldsmobile, not Buick, and certainly not Cadillac.

Other than assembling it 'snugly' with the fasteners provided, you could put something slippery between mating surfaces...hoping that movement between them would not generate any audible vibrations (and will not fall apart); or you could put some adhesive between them...hoping that you never have to disassemble them again.

I know what I do...and what I think most C3 owners do: clean the mating surfaces, make sure the fasteners and the mating parts which engage them are in good condition, tighten things up properly without stripping, distorting, or breaking anything....then enjoy the car for what it is. If you want {quiet}, buy a Mercedes.

 

I have had remarkable success with quieting the distracting (and sort of embarrassing) rattle-trap interior noises. Perhaps its just me and OCD or something but I can’t buy that bad noises are something to be tolerated and appreciated for their era and originality. I have slowly reduced or eliminated most noticeable interior noises whenever an area was disassembled for repair or maintenance. I did it by simply and very discretely applying 1/8” adhesive sponge door/window sealing foam tape (HomeDepot) to one of the plastic mating surfaces before reassembling everything. It has made a world of difference in reducing interior noises and making the driving experience more fun for all involved. Also, installing an adhesive foul-backed ‘dynamat’ to my interior floor pan while already replacing my carpet must have eliminated about 1/3 of them in a felled swoop.
There is nothing you can do to insulate from the plentiful, normal NVH issues in our C3’s, but you can now have a distraction-free conversation. Having the wheels balanced also did wonders -
good luck -

 

I’m certainly not trying to make a sterile sound booth out of the car (I have a C7 for that)! But through this whole interior renovation process I’ve had many “what the hell, might as well fix that” moments while everything is disassembled. Honestly I’m just eager to get the thing done so I can take her out for a spin!

I like the weatherstripping idea. Wasn’t sure if it would fit well and allow dash panels to go back together appropriately. I appreciate the suggestion.

 

I think Lakeside is suggesting 1/8" thick weatherstrip foam with adhesive backing which will mostly compress when placed between two mating [and fastened together] parts.

Worth a try if that is such a big deal for you. Not sure how long that foam will stay viable. If there is movement in that joint, the foam will erode, eventually.
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But, while thinking about this some more, you might try putting a light wipe of Loctite "High-Tack" gasket sealant between such parts. It never hardens and you can separate pieces after years of use.

 

Those guys in the midst of a car 'build' or have their dash out for a replacement, could consider fabbing up extra bracketry in the back.

 

For the sake of resolution and hopefully someone else’s benefit in the future...

I reinstalled my dash a couple of days ago. Tried to place some thin weatherstripping along the front edge of the dash, but wound up with some trouble with it staying adhered so not sure how much stayed in place against the firewall. Probably has to do with all the damn humidity we’ve had with the recent rains down here. So as an additional desperation move, I ran a strip of duct tape along the firewall lip where the dash clips in. Had a chance to take a nice long drive yesterday and it seems to have solved the problem.

Squeaks are a trivial matter and certainly expected from these cars, but any chance to remove some distraction from glorious BB engine noise and the wind in my thinning hair is welcome! Carry on.

 

liked: ...wind in my “thinning” hair

 

The 69 factory sidepipe muffler system does a good job getting rid of annoying body squeaking sounds. The absolute champion system is a BB with headers and sidepipes with minimal/no mufflers....no squeaking, no wind noise, road tire noise, no annoying chatter from the passenger's seat. Another advantage is that you'll have absolutely no interest in buying an expensive sound system for your car...save $$$$.

 

Look up UHMW (ultra-high molecular weight) tape.

It's very expensive but it's an amazing product! It stops glass rattling in my Lord of the Rings pinball machine with greatly upgraded loudspeakers (think bass). It keeps my 1960s contractor-built kitchen "tipper" (sans hardware) drawers gliding smoothly and easily to include the "junk" and tool drawers that easily weight 30# or more. I even used it in a thicker form without the self-adhesive to make a solid masonry (cement board and tile) gravity-anchored service access "end cap" with storage for a very large Jacuzzi corner tub. It easily weighs 200# but slides away with ease despite giving all appearance (and horizontal seal along the tiled lip) of being permanent..

 

Excellent advice! I actually got the original radio up and running as part of my recent interior work. Decided not to go into anything more advanced than the original. My drive yesterday confirmed that the car will drown out anything. And I’m totally fine with that!

 

man that sounds like a miracle product!

 

It is!