Repair: Olympus OM 28mm f/2.8
Bought this lens while picking up an OM-1n body from a former professional photographer here in Seattle. We got to talking and she mentioned that she had some other stuff in a box and I came home with a book, the lens, a cable release, and some other bits and boops. The lens is a really nice 28mm with a decently fast 2.8 aperture, it's super sharp up to f16, and it's tiny. However it came to me non-functional, the aperture ring was jammed tight and no amount of pushing and pulling would get it to move, and the aperture blades were sticky.
For the aperture ring, many Olympus lenses use a small ball bearing to provide a detente between f-stops. My hypothesis is that the ball bearing had moved out of it's little hole and had become jammed under the plate that moves over it. The fix for this issue involves opening up the front of the lens, unscrewing the name ring, and then readjusting the ball bearing.
This lens the name ring has spanner holes that are deep set and my spanner can't reach them. I tried to use a lens rubber tool (it's like a little rubber cup that you can use to unscrew plates with friction), but that didn't work. I tried putting the lens in the freezer for a few hours. I tried lubricating the threads with some Ronsonol. Really nothing worked.
I built this contraption to get more pressure on the name plate. One of the problems I was having is that this rubber cub set isn't very stiff and will fold with enough pressure. This set up gives more structure to the cup. With the lens turned upside down and pushing down into the table I pushed pretty hard, the name ring didn't move... but the aperture ring did! After that the ring moved perfectly with a really nice perfect clickyness.
For the sticky shutter blades involves opening up the other side of the lens. It's pretty straightforward, three screws hold the back plate on. Mine were pretty tight but a drop of Acetone got them moving. Below the plate there is a trio of plates that interface with the aperture check and lens release buttons on the side of the lens.
The common failure point for the blades is for a bit of lubricant to drip down onto those plates and just increases the friction enough to drag the blade movement down. A little IPA and a cotton swap to clean them up got them moving nicely again, and with that the lens was back in action.