Does anyone know how to remove the gas cylinder tube from a Czech Zb.Vz26?

There is a locking plunger, which moves out of the way ok, then it seems the tube should unscrew, but it won't move.
-I presume the gas tube is standard right hand threads?
The tube won't budge, but there is a small amount of rust around the junction.  Will try penetrating oil and then heat, if nothing else works.

Also, once it's anchor screw is removed, does the complete rear sight base assembly remove from it's dovetail towards the top, or bottom, or either way?

Thanks.

Yes the gas tube has normal right hand screw threads and will unscrew. The usual problem is they are extremely fine threads and its an area where corrosive ammo, dirt, rust can eventually get over 70 years of life and become very stuck. Original ones seem to require tube destruction in order to remove it. i advise leaving it alone unless you have to replace it. Also the heat you will have to use will destroy the detent spring that was used to keep it from rotating.

The rear sight is held in the dove tail by a grub screw that is hidden by the dial for the rear sight. Once you remove the rear sight wheel, you can see it and back it out completely before trying to remove the sight base.

My C&R transferable ZB26 made in 1931.

BTW you need to have the buffer in front of the trigger guard or you can have problems with the eject brass sometimes coming back into the gun. I made a drawing for making new ones if you need it. The ZB26 also does not like the heavy 8mm ammo but prefer the lighter ammo. The Czechs had adopted the lighter 8mm ammo. The ZB30 changes were there to address the use of the heavier 8mm other countries were adopting. I bought 27 cases of the Rommy 8mm ammo back when it was cheap for my ZB26 since it was hte only surplus with the light bullets. It runs great with it though its corrosive and has to be cleaned after shooting.

Attached File
You can see the grub screw in this section drawing, its number 104.

Thanks very much.  
Knowing the gas tube thread is right hand will at least keep me trying in the right direction.
I did get the grub screw out, but was not sure if the rear sight assembly can be pushed out of the dovetail in either direction, or one direction only.
Thanks to your side diagram, it looks like it has to go out towards the top, as there is a ledge near the bottom.

Yeah the sight base only comes out of the top. It should not be that tight int he dove tail. Just tap on it with a rubber/plastic mallet straight into the receiver a couple of times and it might might break loose.