Sound Encapsulation Panel Restoration - PeachParts Mercedes-Benz Forum

matt87_300d · #1 02-24-2007, 10:28 AM

Hello,

I finally managed to track down a set of the anti-noise / sound encapsulation panels that go underneath the engine and transmission on my 1987 300D. $650 always seemed like way too much money to pay--thank goodness for CraigsList!

I believe that the panels, when new, had some sort of coating on the inside surface, however on the panels I bought it is all corroded away by twenty years of aging and leaking, etc, so I can't really tell what material originally coated these things.

There are images of the new panels, with a foam-like coating at:
http://www.w124performance.com/images/W124_stuff/sound_panels/new_87_front2.jpg
http://www.w124performance.com/images/W124_stuff/sound_panels/new_87_rear.jpg

Has anyone ever attempted to re-coat these sound panels? What material and adhesive did you use? It would have do be something oil / transmission fluid / coolant resistant. Or does it really matter...should I just put them on as bare plastic panels?

Looking forward to a quieter idle!

--Thanks,

--Matt

babymog · #2 02-24-2007, 11:27 AM

Fix the leaks first, then consider insulation that you can buy many places such as JC Whitney with the foil surface and open-cell foam beneath.

I believe that the original is an open-cell foam with a facing material, heat-pressed/molded onto the shell. On my '91 I had a leak, didn't know it until that panel was pretty full and started dumping fluid, what a mess. On the other hand, 4matics were famous for leaking anyway, ...

How fortunate for me that an oil-change jockey tossed it for me without my knowledge, by the time I noticed everyone played stupid, no way to recover it.

Rob124 · #3 02-24-2007, 11:45 AM

I've read that it does make things quieter to have the foam present, but I have the same problem with mine. See www.aircraftspruce.com/menus/ap/soundproof.html for some aircraft-oriented solutions which might work on these panels. I've used some of the closed cell vinyl-nitride foam with pretty good results, but not on these panels, yet.

For the front panel, it appears that one could cut the foam to fit, then brush glue onto the panel, and then vacuum bag the whole thing to produce a form-fitting appearance, as per the photo. I think I'll try that.

The material on the rear panel looks altogether different, and is probably expanding foam, which was put in place with the help of a mold. I'm not sure I want the mold to be the bottom of the car, however!

I've used Dynamat Extreme elsewhere on the car with good results, but don't think it's a good solution for this application.

Maybe someone has actually done this, though. I'd be interested.

matt87_300d · #4 02-24-2007, 12:00 PM

Thanks for the ideas. Fixing the leaks is certainly a good idea, but given how frequently new ones seem to pop up, it would be nice to use a material that's resistant to chemicals.

I found a product called "VB-TS" by Cascade Audio Engineering that seems like it fits the bill. It is 3/8" foam with an aluminum / mylar surface, and they claim that oil does not penetrate after two months. Not wonderful, but better than anything else I've found.

The spec-sheet on the material is available at:
http://www.partsexpress.com/pdf/268-280.pdf

Also, there are ebay sellers selling it for ~50% of retail. $50 for 14 square feet (VB-TS) / $100 for 28 feet (VB-TSXL).

This does not really match what it looks like the stock material is in the photos I posted links to, but may be a good solution nonetheless.

Rob124 · #5 02-24-2007, 12:37 PM

Matt,

If it has an aluminum surface, it may not absorb sound like the original foam. I think the issue here is sound absorption, vs. vibration deadening. That's why I decided not to use Dynmat on these panels--they're good at deadening body panels, but wouldn't do much about absorbing noise. That's why Mercedes used foam in these panels, I presume. If you get some of this stuff, let us know how it works, please.

jbaj007 · #6 02-24-2007, 01:36 PM

Why not try to incorporate something like this:

http://cgi.ebay.com/ebaymotors/Oil-absorbent-sheets-auto-diesel-marine-fuel-105-EA_W0QQitemZ4618776569QQihZ002QQcategoryZ63703QQrdZ1QQssPageNameZWD1VQQcmdZViewItem as a removable drip control device on the panel(s) or on a skid plate? In addition to the foam.

http://cgi.ebay.com/ebaymotors/Oil-Absorbent-Pads_W0QQitemZ4567350348QQihZ002QQcategoryZ26455QQrdZ1QQssPageNameZWD1VQQcmdZViewItem

Jeremy5848 · #7 02-24-2007, 01:37 PM

The panels on my wife's '87 didn't have anything on them (except a lot of old oil and dirt).

I was able to scrape off most of the crud and put the panels back as they were, not knowing anything about an inner liner. I don't think I could get anything to stick to the plastic anyway, given all of the oil that has been on the plastic for years, but just the panels alone help quiet the car. I'm looking forward to installing new padding on the hood, that should help too.