Compound shutter Piston cap removal?

[JimboWalker]

I have a compound shutter that I may try to repair myself. The piston end caps are very hard to turn. Is there a possibility of a reverse thread with the caps or just stuck and need pliers? If I do enter the and remove the piston, what precautions do I make and how do I make sure the caps seal again. I'm sure the seals on the caps will probably leak after I break them loose. Thanks!

[pjd]

What's the problem with the shutter? If it's firing at one speed, probably the piston is stuck. If the slow speeds are too slow, the piston housing is probably a bit gunked up.

The best way to get at the piston is to remove the top cover of the shutter. You can't clean up the inside thoroughly without removing the piston assembly. The piston assembly is held in place by two screws, removing those will allow the piston to be removed and you'll have easy access to the caps and the retarding slug. Don't use pliers, it'll mess up the end caps. Removing the piston will allow the caps to be gripped more easily. No reverse threads involved, if I recall correctly.

If you aren't comfortable removing the top cover send it to a shutter repair expert, save yourself the time and hassle.

[JimboWalker]

I am sending to Bob Watkins. Thanks!

[Ron (Netherlands)]

I've serviced quite some compound shutters (most easy to do yourself); there are no seals inside!
Clean the piston and the tube with alcohol.
seen these? :

https://lommen9.home.xs4all.nl/shutters/compound/index.html

https://skgrimes.com/rebuild/products/shutters/compound-shutters/

https://www.rangefinderforum.com/classics/forum/messages/20735/15828.html?1247800588

https://www.largeformatphotography.info/forum/showthread.php?68498-Compound-Shutter-guts