Thanks for the link. It looks like the same issue though and I think it's because I have manual brakes that causing the problem. The Dorman M75817 was the second master I received and it had the same large rear res issue even though the description was right. What I got this time was the second 10-1493M and it also has the large rear res and it'd description is also correct. I called Napa again and they can't get them at all either. How can 2 manufacturer's have correct description and the wrong part? Maybe I'm gonna be stuck running this master. What would happen if I did?