New Old Stock RB67: Disintegrated Light Seals and Dark Slide Seal
Originally posted on Instagram. Notes from the repair bench, kept here as a searchable archive. View the original on Instagram
Sometimes, getting a new old stock camera in the original box is not ideal. This RB67 and back arrived looking like new, perhaps unused or very lightly used. Along with a 90mm lens, they were from the late 1970s since the boxes had labels from Bell and Howell who were the distributors of Mamiya at that time.
So, while cosmetics were very nice on the body, all of the light seals were disintegrated on the body, back and revolving adapter. And, the mirror light trap was not returning. All of this was due to age of the seals and dried lubrication. I also replaced several pieces of leatherette that had dried up and were curling. The lens, which looked great, had separation on an inner element, probably due to long time storage in a hot, humid area.
I get contacted regularly about light seals and I generally suggest DIY on replacement. Not difficult but can be time consuming to clean all the passages. In this case, I did the replacement of the seals since I was going to work on other systems of the body.
Speaking of light seals, one seal that is not included in the kits being sold is the dark slide seal. In some cases, this seal may not need replacement if the back shows little use as it does not disintergrate from time like the other seals in the back. The dark slide seal gets worn with a lot of use (sliding the dark slide in and out). Since this seal is not usually sold, you have to make one up for yourself if you don’t have a supply. You can remove the old seal and glue on a small strip of velvet. The final photo shows some of these dark slide seals with a new one at the left in the photo and a worn one to its right.
