Front shock undercoating -- what is it?

[Jastx]

I just had new shocks installed on my 1989 930. In the interest of keeping it original looking, I'd like to replace the undercoating-type material that was removed inside the trunk to install the new shocks.

What exactly is it? Where can I get it? How was it originally applied? Looks sprayed on...

Thanks!

[RickM]

You can use Wurth SKS Stonegaurd which is sold here (You'll need to call as I don't see in the catalog). It is sprayed on at the factory.

You can buy the Wurth gun for $$$$ or a Harbor Freight unit for around $7. For touch-ups you can also use a brush to dab it on.

HF gun: http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=43761

[Tex3]

Jastx,
Depending on how much undercoat you need will determine spray can or pistol method personally I used a sears sand blaster pistol and wurth per quart. Not as thick as I would have like but I guess the spray can will give you the same results. Again pistol method works for me best since I will be using it in the near future



Finally finished my gas tank!

[Rot 911]

If it is the stuff around the top shock mounts I don't believe it is the Wurth Stone Guard. More like a hard tar substance.

[Jastx]

Right, it's the stuff around the top shock mounts. It dries non-sticky. This stuff:

[DW SD]

Just curious, why? I'd leave it until you are ready to enter a concourse or some other event. I've found a number of reasons to want to take it apart with that messy not in the way.

Just another perspective. I cannot blame you wanting to keep things original.

[Jastx]

Interesting point. My car is more concours oriented. I would condsider leaving it if I had the material available to return it to original on hand. From the responses, I'm still unsure what that is.

[randywebb]

it helps hold the alignment - dunno how it was applied originally

[strupgolf]

I just had a front end aligement and the guy said he could not adjust things right until the black gunk is off. Does this sound right or what. Thanks

[Wil Ferch]

Sounds correct....needs to come off to allow movement for an alignment....

Wil

[randywebb]

agree - IFF there is so much buildup he can't move the plate where he needs to go

My alignement shop has never had to do that tho.

Bottom Line - if you trust the shop, do what they say...
If you don't trust the shop, find another or do it yourself...

[RickM]

.... but what is this stuff ? .......

[randywebb]

some kinda black gunk (That's the technical terminology, of course)

....

It seems asphaltic, tarry... my guess is that it is derived from a lower level refined petrochm. with something added to make it better for this use.

Some work with Google might be productive.

Otherwise, it would be time to make like an analytical chemist and get anal on it with some big instruments - not cheap even if you have friends you can ply with beer....

We don't seem to have evolved a hobbyist mass spec. yet -- unlike woodworking & machinst areas.