Hood Insulation W123 - PeachParts Mercedes-Benz Forum

Guest987 · #1 10-04-2014, 12:49 PM

I am intending to replace the hood insulation on the 240D. I wanting to ask if it is better to remove the hood to do this? I have read some posts on people doing it with the hood in place. Also, what do you prefer on the method and cleaner on getting the old glued on pad off with? Mine is flecking off all over in the compartment. Ones I noticed for replacement seem to be the ones with what looks like an aluminum covering like... for the cars with the turbo.

fahrvergnugen · #2 10-04-2014, 01:14 PM

What I did is just wash off all the old stuff at the car wash, use some 3M Super 90 adhesive as directed, and get some help on the other side of the hood... Worked out fine.

charmalu · #3 10-04-2014, 01:53 PM

You do not need to take off the Hood to replace the Pad.

Here is a single post from a thread I posted in.

Be sure to use 3M 8090 spray adhesive.

Finally gave up on hood pad; anyone want to convince me to replace?

Just in case that thread ever get deleted.....

I replaced the pad on 2 W123`s this summer by my self.

Lay a plastic tarp, sheet etc... across the engine. this will keep all the crumbling pad off the engine. pull down big pieces and scrape off what you can with a putty knife.

Then I raised the hood straight up, got on the engine and wiped the surface down with a wax and grease remover. a product used when prepping the body for paint.

Mark the center of the hood top and bottom with a felt tip marker. do the same with the pad.

masked off the windshield and eng bay, then using 3M 8090 spray adhesive sprayed the hood area with 2 coats. then sprayed the pad with 2 coats for good coverage.

Let it get tacky.

Fold pad in 1/2 (none glued side) and line up the centering marks on pad to the marks on the hood. make sure the top corner is lined up as well as the bottom corner. then smooth it down, then do the other side.

Run your hand across the pad with some pressure to make sure the pad is secured to the hood.

It did make the 240 a little quieter.

Charlie

PackerEdgerton · #4 10-04-2014, 08:53 PM

My hood install was just done a few weeks ago. I followed Charlie's method, but put one of those multi-purpose ladders across the engine bay and put plywood across the top to have something stable to stand on.

I did use a Dremel vibrating multitool with a scraper blade across the entire surface. I also wiped it with lacquer thinner to take off as much of the glue as I could. I wore heavy long-sleeved gloves and a lacquer-rated VOC breathing mask the whole time.

I used 2nd Skin Audio's "Hood Pack" which works quite well. For details, refer to my thread "The Quest for Quiet"

Good luck

Packman

97 SL320 · #5 10-04-2014, 08:57 PM

Also, a good hood pad will save your paint from baking. ( hot motor )

Stretch · #6 10-05-2014, 04:53 AM

If you decide to remove the hood / bonnet to do this job then you need to have a really good place to support it and not scratch the outer paint job. As said above you don't really need to remove this body part from the car to do the job but it does mean you don't have to clean all the muck you might leave behind in the engine bay. (Obviously covering the engine bay with an old blanket will catch a lot of it - but think of the paint work on the wings / fenders whilst you are rubbing yourself up against them!)

leathermang · #7 10-05-2014, 08:58 AM

Before you take the hood off.... be sure to mark the position of the brackets which attach to the hood.... I suggest with a scribe... it can make all the difference in getting it back on and fitted correctly...

funola · #8 10-05-2014, 09:50 AM

The most important advise I can add is that when spraying the adhesive onto the foam, you want it oriented like painting a ceiling. Hang the foam from 4 corners and spray upwards. Reason being the foam is a sponge, if laying flat, the adhesive will soak in and sink to the bottom (instead of being on the surface) and most of it will not be doing its job. If hung, the adhesive will stay on the surface and provide maximum adhesion.

Guest987 · #9 10-05-2014, 11:08 AM

I had a question on cleaning off the old adhesive. Will brake clean get it back off ok? This particular hood had had the pad replaced once. The person that did it got really wild with spraying the adhesive on the underside of the hood. I was hoping I could get it off without destroying the painted finish. Also, I would like to know if there are different qualities of the hood pads? The one on there you just touch it with your finger and it leaves a permanent indentation in it, and you have like greasy fuel on your fingers. The top covering just comes off too! It was like maybe a fuel line had come loose, and sprayed the hood insulation pad.

dkr · #10 10-05-2014, 11:18 AM

I've done this a few times and see zero upside to removing the hood. The downside is that you may scratch the paint, dent it and misalign it when you reinstall it.

Dkr.

charmalu · #11 10-06-2014, 04:59 AM

Quote:

Originally Posted by Stretch

If you decide to remove the hood / bonnet to do this job then you need to have a really good place to support it and not scratch the outer paint job. As said above you don't really need to remove this body part from the car to do the job but it does mean you don't have to clean all the muck you might leave behind in the engine bay. (Obviously covering the engine bay with an old blanket will catch a lot of it - but think of the paint work on the wings / fenders whilst you are rubbing yourself up against them!)

Do it Naked.

Charlie

Stretch · #12 10-06-2014, 08:45 AM

Quote:

Originally Posted by charmalu

Do it Naked.

Charlie

I've been told some people have a rubber fetish but a dried up hood foam fetish?

leathermang · #13 10-06-2014, 09:54 AM

Quote:

Originally Posted by funola

The most important advise I can add is that when spraying the adhesive onto the foam, you want it oriented like painting a ceiling. Hang the foam from 4 corners and spray upwards. Reason being the foam is a sponge, if laying flat, the adhesive will soak in and sink to the bottom (instead of being on the surface) and most of it will not be doing its job. If hung, the adhesive will stay on the surface and provide maximum adhesion.

On the other hand.... some spray cans are made where the pickup tube is such that it needs to be in an upright position... read the instructions for what ever you buy....
but it might also be fine for the foam to be vertical ... like a wall.... long enough for it to ' tack '.....
And on another hand.... contact cement should be applied in several light coats... if more than one coat is needed.... and that by itself will usually keep it from ' soaking ' in.....

remember.... 8090 is the magic 3m number...

Guest987 · #14 10-06-2014, 09:55 AM

I might break my ?? standing on the motor with my goggles on!!

Stretch · #15 10-06-2014, 10:18 AM

You most certainly want to look after your ??