Check out the link below with the repair, it should have all the necessary parts listed as well. If you have anymore questions, give us a call at 888-280-7799 and one of our MBZ parts specialists will be happy to help you out.
Mercedes-Benz W123 Self-Leveling Valve Rebuild | W123 (1977-1985) | Pelican Parts DIY Maintenance Article
-Dmitry