K-Jet, as for availability: it used to be available at Mercedes, I bought it there 2 years ago. Now you can buy those Mercedes solenoids in the internet stores for higher prices. Such is life. I assume you know what is available in internet stores and on ebay (at least 2-3 offers on ebay). If not, let me know, I will share.
As for repair - yes. There are several threads on the Forum, you just need to use the Search function. Type in what you want to search for e.g. in parenthesis "Constant Speed Solenoid" - you will get about 150-200 hits to look through by topic. If you type in just CSS, 17 hits.
When you look through it, you find threads like this:
https://www.sl113.org/forums/index.php?topic=27065.msg193973#msg193973I do not mean to be preaching, I found out for myself that reaching some fluency level in working with search function just made my life easier.