knocking sound in body-C3

[BangkokDean]

Recently I have a noise coming from the driver’s side at the top near the seat belt re tractor. I have removed the re tractor the t-top and the noise is still their. It sounds like metal bumping. After many drive around the block with all the trim removed and the re tractor removed I have come to the conclusion that the bird cage has some how separated from the top roof fiberglass, you can’t see any separation but I think when the body flexes the bird cage is hitting the outer fiberglass causing the knocking sound. I don’t see any way to bond it with out some major work. What I am thinks is to drill a few small holes on the inside of the birdcage and use a spray bomb of the expanding insulation foam, filling the space so the metal cage is not hitting the fiberglass skin.

Does anyone see a better solution?Or can think of what may be causing the knocking sound?

 

[Twin_Turbo]

The fiberglass is glued in a couple of spots, above the door edge (where the glass notches and flows into the roof bar) and directly in the middle behind the T bar. These are just big dabs of adhesive and a bitch to get to. I doubt that's where your noise is coming from. There's a good amount of room between the glass and the metal, it would take a lot of distortion to make a noise there. Tracing a noise can be very deceiving, make sure it's not something else first.

 

[BangkokDean]

The fiberglass is glued in a couple of spots, above the door edge (where the glass notches and flows into the roof bar) and directly in the middle behind the T bar. These are just big dabs of adhesive and a bitch to get to. I doubt that's where your noise is coming from. There's a good amount of room between the glass and the metal, it would take a lot of distortion to make a noise there. Tracing a noise can be very deceiving, make sure it's not something else first.

If I take the T-bar off can I see the bonded location? Also do you think it will do any harm to shoot some expanding foam in between the metal cross over and the fiberglass roof? I am always looking for something else that could be the noise. It seams like it is right at my left ear.It not in the door or the T-tops as when I drive with the door open and tops off it is still there. I at one time thought it was the body bolt next to the trailing arm as I have just replaced the bushings on the trailing arm. But cant see that it is coming from that point.

I will keep looking, if the foam does not do harm I may go with it.

 

[mrvette]

I'd be all OVER those body mounts, #3 as you said above, and #4 behind the rear wheel, #4 is a famous rust out spot, I had to do mine long time ago...

:gurney::beer:

 

[Twin_Turbo]

If I take the T-bar off can I see the bonded location? [/quote[

No, it's on the top towards the rear window. If you remove the interior halo trim you might be able to see it with a small flashlight and maybe a dentists mirror.

Also do you think it will do any harm to shoot some expanding foam in between the metal cross over and the fiberglass roof?

I'd be worried about the foam retaining moisture. There's no coating whatsoever on the birdcage and with the leaky t tops right there, asking for problems.

I am always looking for something else that could be the noise. It seams like it is right at my left ear.It not in the door or the T-tops as when I drive with the door open and tops off it is still there. I at one time thought it was the body bolt next to the trailing arm as I have just replaced the bushings on the trailing arm. But cant see that it is coming from that point.

I will keep looking, if the foam does not do harm I may go with it.

Have you tried the t top receiver? How about the door striker bolt? It threads into a captive nut, the cage for it however is pretty long, a lot longer (taller) than the adjustment in the fiberglass panel over the pillar. IT loose it will rattle.

 

[DeeVeeEight]

These noises travel and are a bitch to figure out, the bodies are like the skin on a drum and transmit vibrations. I might take a look at the shocks, diffy and sway bar bushings to see if anything has movement.

 

[BangkokDean]

Have you tried the t top receiver? How about the door striker bolt? It threads into a captive nut, the cage for it however is pretty long, a lot longer (taller) than the adjustment in the fiberglass panel over the pillar. IT loose it will rattle.

I will check that out.

These noises travel and are a bitch to figure out, the bodies are like the skin on a drum and transmit vibrations. I might take a look at the shocks, diffy and sway bar bushings to see if anything has movement.

I am thinking to get it up in the air to see what I can see. Thanks guys

 

[MYBAD79]

If you really want to go for the foam, check out www.uscomposites.com - they're in south FL and I have some of their structural foam... good stuff.... don't think it retains moisture like the "great stuff" foam you buy at the hardware store.