When I removed the clutch cylinder on my '60 BN7 for a rebuild, I found an aluminum shim behind the lower mounting bolt. This is a commercially made piece that follows the profile of the flange through which the lower bolt passes. It was trapped behind that flange and fire wall. The 1/16"-thick piece is slotted so that it can be slid between the firewall and the cylinder flange without fully removing the bolt. In addition to that slot, the piece has a half circle cut that reaches midway around the circular portion of the cylinder that goes through the fire wall. I know this piece is commercially made, as one side is raised around the outer perimeter, something that would be extremely difficult to do by hand. I have also recently replaced the brake master cylinder, and no such piece was found on that. Naturally, I forgot to install the piece when I replaced the clutch cylinder, and then lost it into never-never land inside the engine bay when I tried to put it back. While looking for it, I found the bolt that I had dropped into that abyss and replaced earlier. Since someone thought it was important to have the shim in there, I made a new one in similitude of the lost part and installed it. Given the generous potential play between the clutch push rod and the clutch pedal, it wouldn't seem a shim this thin would be a necessity. Postscript! Of course the missing original piece belatedly was found and is on my desk as I write this. I looked in vain for an identification of this part in the factory Service Parts List for the BN7/BT7 cars on Larry Varley's comprehensive Healey Web site. Happy to say I seem to have successfully rebuilt the clutch cylinder and bled the clutch slave, meaning that I now have to restore the transmission cover over my Smitty Toyota gear box and the balance of the car's interior. So, has anyone ever seen such a piece? I now have some scan capability, and could likely figure out how to post a picture.