Yashica-C dismount shutter

[lozhka]

I did not spend much money on this Yashica-C, so I thought it would be a nice learning experience to try to "repair"/clean the shutter. Of course, it would be great if I could actually manage to get it to function again.

I'm roughly following these instructions: http://ratfactor.com/yashica-d-tlr-copal-mxv-shutter

Now I got to the part where I should unscrew the black "tube" from the mounting plate. This is the "stage" I'm at now, I removed the lens to make sure it doesn't get damaged:

This is the front:

I tried everything, but can not unscrew the tube. I can't get it loose. I looked for other instructions and experiences, but it is always said to remove the black tube and then the shutter should get loose. I tried looking for a way to dismount the shutter from the front, or a way to take out the mechanics as a whole and work my way down, but no chance. I do get access to the mechanics, but it doesn't look like I can take them out as a whole somehow, without having to take them apart completely.

Has anybody had this same problem and/or knows what to do to dismount the shutter element to get to the back of it, to access the blades?

My goal is to clean the shutter blades, as I assume that they are stuck/greasy. The mechanism seems to be working fine, I can set the shutter speed using the ring, cock the timer with the "handle" and more or less release it. On releasing, the blades do not open immediately, I have to wiggle the release button until the blades are fully open, then they close again nicely, after the appropriate time. This hints that I have to clean the blades, is that right?

So, two questions:
- Is it right that I should try to clean the blades? (I plan to follow the instructions from the link for this)
- How on earth can I get access to the blades? I've spent a whole day on this and I'm close to going nuts.

 

[shutterfinger]

Looking at your picture #1 the "black tube" is likely rusted in place. Cider vinegar will dissolve the rust. You may need to put some penetrating oil https://www.amazon.com/LIQUID-WRENC...d=1488751637&sr=8-15&keywords=penetrating+oil on the threads between the tube and shutter and let it sit for a day or more to get it loose.

http://pheugo.com/cameras/index.php?page=copalmxv
I doubt its the shutter blades causing it to be sluggish, its likely the delay mechanism, release mechanism, and blade controller dirty and dried out.
A full Clean and Lube is in order, I do not know if there is anything to adjust.
When removing the front cover, mark one of the slots in the retaining ring and count the number of turns to remove it then record for reassembly.
Take good pictures of the shutter as you disassemble it to aid in reassembly.

Shutter and aperture blades should be free of oil and grease. Never use oil or grease on them.

 

[John Koehrer]

The only thing holding the lens ONTO the board is the black tube.
Access to the works will be through the front. The silver spanner ring is holding
the cover plate. Taking it off will generally give access to the guts.

 

[lozhka]

@John Koehrer
Took a look at the mechanics, but I intend to get access to the actual blades and I think I will still have to go in from the "back" for that.

@shutterfinger
Thank you for your reply and the advice! I will definitely try cider vinegar and eventually the penetrating oil.

In the meantime, I put a few drops of lighter fluid on the blades and "shooting" worked perfectly, as long as there was fluid on the blades. The timings seemed to be right (as long as the blades were covered in the fluid). After a few "shots" some greasy stuff appeared on the blades, I very carefully cleaned it off with a q-tip and it was yellow. After repeating this process for a few times, the shutter seems to be working now. However, I have read about experiences that ended up with the blades being stuck again soon after reassembling and using the camera for a while. Is it a good/wise idea to still try to completely clean the blades by disassembling them, or should I just do the mounted cleaning (with the fluid and the q-tips) a few more times/days, before reassembling? I am actually a bit curious to see how the blades are working exactly, so I might still open it up to take a look.

 

[shutterfinger]

I deplore the use of lighter fluid. Its main ingredient Naphtha, softens the dried out lubrication but does not remove the fine metal filings and dirt that have accumulated over the years and redistributes it to places that it should not be.
Putting solvent on the shutter blades and it loosens up says the lubricants have run down onto the blade controller and blades so just flushing it with solvent is akin to pouring 100 mesh sand into a good shutter.

Taking the front cover and speed ring off, putting the shutter face down in an ultrasonic cleaner, covering with 90% Isoproply Alcohol, and running a few cleaning cycles of 3 to 5 minutes each allowing the alcohol to cool every other cycle will be almost as good as a full disassembly and clean and 100% better than flushing with solvent.

 

[EdColorado]

I'll second what Shutterfinger said here. Just please please allow the alcohol to cool as he said, its amazing how hot things can get in an ultrasonic cleaner.

 

[lozhka]

Thanks, both of you!

Is 90% better than 96% alcohol for this? Nevertheless, it seems impossible to get that damn black tube off the plate. I'm starting to think that somebody glued it to it and I'm close to giving up. Putting the shutter with the plate (edit: the big back plate that also holds the upper lens) and everything in a bath does not make a lot of sense to get the blades cleaner, I suppose? As it would only wiggle around the dirt inside the "box"?

PS The mechanics that are visible when I remove the front cover plate seem to be working fine and run smoothly, which is why I still suspect the blades or the "base" of the blades to be the cause of trouble.

 

[shutterfinger]

The things I do to get stuck retainers off are
1. penetrating oil keeping the joint moist with the oil for up to 3 days when rust is apparent. I have left some non critical parts in penetrating oil for a week before they came loose.
2. heat an oven to 250°F-275°F (221°C-235°C), place the part in the center of the oven, turn the oven off and leave the part for 30 minutes then try to remove the stuck parts being careful not to burn my fingers/hands. Some place the item in a freezer for an hour or two but moisture condensation can be a problem.
4. heat with a small torch.
https://www.amazon.com/Bernzomatic-...F8&qid=1489024201&sr=8-5&keywords=micro+torch
5. use a rubber strap wrench strap and a 12 inch curved/V jaw pair of tongue and grove pliers. Place the rubber strap in the jaws of the pliers to prevent marring then grip the ring. Too much pressure can deform the ring.
https://www.amazon.com/Task-Tools-T...8&qid=1489023626&sr=1-2&keywords=strap+wrench
https://www.amazon.com/Channellock-...1489023694&sr=1-14&keywords=slip+joint+pliers
Be persistent!
The shutter blades have been the cause of less than 1% of the 50 + shutters I've serviced.
Water is used to dilute alcohol so the higher the percentage of alcohol the less the water content, the less water the better. Denatured alcohol will dissolve adhesives, may damage paint and harm other parts used in shutters therefore I do not recommend using it.