Back in the 1990s I had purchased a used film magazine, which caused intermittent misfire with my new (not purchased used) ETRSi body. The film-advanced interlock pin in the magazine protruded too far into the body. As a result, the mirror would swing upward, but it was prevented from swinging up fully all the time. As a result, the lens would sometimes be prevented from actuating the shutter and the flashing red LED in the viewfinder would not indicate shutter fire. If I mounted one of the film magazines which I had purchased new, there was not a problem...it happened only with the one used magazine, and intermittently. I needed to send both body and back to Bronica repair facility, where they shortened the pin on the magazine so it would not cause the mirror to make incomplete upward motion.
So now with the lube I've got it working 40% of the time. I guess I need more lube or different lube.
After days of cleaning and re-lubing, letting it set in. Running it through all speeds at all lengths I find that at infinity, it works. Focusing in past the 5 foot mark it starts to hang, and anything past 4 will not fire unless "helped".
This lens is basically unusable to me. However, I wonder if the springs in the body that cause the rotational force are just weak from use. Because of the design of the lens, racking it out would cause force to fall off exponentially,
if I remember my physics. Anyone else want to chime in?
I now need to figure out if it's worth a full CLA, body and lens - or do I need to sell it and seek out a new camera. To tell the truth, I don't think I would mind selling it if I could find a decent back for my Speed Graphic (that wasn't $600!). Decisions, decisions...
Force should not fall off at all, because the actuation arms which extend into the lens and transfer the motion from the body to the cam plate, move in a fixed arc, regardless of what point along those arms the cam plate makes contact with them.
A few things to consider: The body does not generate much force on release. The pins must have only a little resistance to being moved at the start of their travel. Cocking the lens requires some force, which provides the spring tension to work the shutter and diaphragm, but once cocked, the pins can be moved in the release direction easily.
Check manually that the pins move easily in the release direction (clockwise, looking at the back of the lens). To release, move in the lock tab located on the lens, inside the mount ring between 4 and 5 o'clock as you look at the back of the lens. The pins will have a slight resistance initially, then move very easily until they reach a detent near the end of their arc.
Check that the rotating piece which is attached to the back plate, and has the pins and actuation arms on it, can move completely freely through its entire travel.
Check that you put those actuation arms into the proper slots in the cam plate (the plate which moves the rollers as it it is turned).
Check that you used the right grease. A light grease which is not sticky should be used, as a thick and/or sticky grease will create resistance to motion.
Check if anything seems to be misaligned and feel if anything seems to be binding.
The critical point is where the rollers contact the cam plate. That is where a lot of localized force is generated, and all the old grease must be gone. The cam plate must move easily in the release direction, and the rollers must follow.