I'm not sure how to do it online either. I would suggest calling the Classic Center's toll free phone number to see what they recommend. Let them know up front that you're an MBCA member and let them explain how to proceed. I've gotten the discount through the years but I've always talked to someone about it and done it that way. Let us know what you find out. The Classic Center has been an invaluable resource for me over the years. They know our cars so well.

Thanks. I called and the person that picked up explained that if we’re using the website, the 15% is already factored into the price. I checked the list price on the regular MBUSA parts site and compared it to the classic Site and indeed the prices on the classic site are lower for the same part. I was also able to score free shipping. I wouldn’t have expected Mercedes to have good deals on such a hard to find part but they were priced less than half of what I was seeing on ebay. I’m going to check the classic site for parts more often.

Thanks for the update. My personal experience has been that the MB Classic Center is an invaluable resource. I've found that Ebay can be way over priced.

Discount even applies at MB dealership. Bought couple batteries for o8 SL not long ago at dealer parts counter, think was 10%

I've gotten the discount at both the MB Classic Center and my local MB dealership for both parts and service work performed..