I was rotating the tires on my 06 Evo MR with 5800 miles and the front left Billstein shock was totally covered in a black coating. Did not think much until I saw that the other three are bright yellow.
I will pull the wheel again tomorrow and look at it, but wonder if anyone can tell me what is on that side that can cause that kind of leak, gear, trans axle, ...?

Thanks guys.

 

Is it dry or oily?

 

Yes it was pretty dry and caked on.

 

Probably just brake dust.

 

That's undercoating. Mine where like that too. One was bright yellow, other was covered in the undercoating.

 

You know it looked pretty thick. I can believe that it is undercoating. Did you remove it or leave it on the shock?

 

I just cleaned the undercoating off mine last nite. Yuck, what a mess. Paint thinner and lots of paper towels will do it. Won't harm the yellow paint either.

 

Thanks Steve_P and razorlab. I will do so tonight...

 

USE some gunk degreaser, works great. I sprayed on, power washed off.

 

Yeap it was undercoating washed it off now I am happy again. Thanks for the help.

 

i would still check your outter cv boot on the axle. something on the road could've cut the boot open and threw grease everywhere. its just one of those better safe than sorry. if you don't catch it quick, your going to be paying for a new axle instead of a cv boot. jack the car up on the side you found the substance and do a quick check of the cv boot and make sure theres no cuts on the boot.