Thursday, January 1, 2009

Diana Modell 5 Disassembly

So as I hinted at earlier, when I shot the Modell 5 recently it surprised me by going off when the barrel was closed on cocking. Not good. Thankfully nothing was harmed as I kept the muzzle downrange and away from my feet. So I had to disassemble it to inspect and fix the problem.

The Diana Modell 5 (The Blue Book calls it the Model V)

Stock screws are removed. I forget which side has the longer screws...not that I did at the time.

The trigger guard is unscrewed and unhooked from the action and then the stock can be removed. I'll call the grips "the stock" as it's made of wood...

The spring sits in the a hole in the stock, just as with the Slavia.

Notice the large amount of schmutz at the trigger.

The barrel was removed from the tube.

The barrel pivot screw was shimmed to time the cutouts with the lockscrew.

The llink is slid forward so that the pin can be pushed out of the enlarged opening.

A clever design of two diameters.

This is actually a shot of reassembly, the tiny pin is what the trigger guard hooks over. Don't lose it...

The trigger pin is pushed out.

The sear and pin.

Just as with every other Diana pistol, I put it in the compressor and removed the end cap.

That's the amount of preload.

You can see a tiny setscrew to the left of the end cap. It keeps the cap from unscrewing but as far as I can tell doesn't bear against anything, just sits within the slot of the tube.

The piston with it's huge block. Notice the shaved bits of leather seal. The bit at the bottom was in the sear interface, likely what caused it to go off...

The piston seal itself was in fine shape. You can see the circuar groove in the attached block. I'm not sure how they attached that block to the piston.

I shaved off the fuzz from the piston. Then I lubed and reassembled in reverse order. The pistol now only goes off when the trigger is pulled. Which is a good thing.


derrick38 said...

Nick, that piston seal is in amazing shape. I didn't realize there was a shelf on the pivot bolt for the locking screw to bottom on. I'd always (wrongly) assumed that it just nestled in the notches and bottomed against the compression tube itself. Very clever arrangement.

Nick Carter said...

Yet I didn't even notice that eyed as always...most I've seen (what about 4?) don't have that ledge.

Anonymous said...

Have just recently discovered your site and think it's great. Your photos are so good and your writing is easy to understand.

Hope someday soon you'll take us through a step-by-step disassembly on that Hy-Score pistol you recently purchased. That would be a great post.


Nick Carter said...

Thanks Mike,
I'm having fun for sure. The Hy-Score is functioning fine, so I'm not going to touch it! They are a little finicky to disassemble. If I find a beater one you can be sure I'll tear into it.

Unknown said...

Hi Nick, I would love to see a Hy Score 800 Catch. I inherited a gun that is missing the catch and can't find anyone that has one. I would love to see some photos to fab one!Or, maybe you can make one?! Thanks Lance

PS Diana V works great Thanks to the blog!

Unknown said...

Couln't get the urathane seal into my Diana 5 sleeve so I made a 1" PVC guide. I heated the PVC evenly then wrapped 3 loops of scotch tape around it. Then I pushed a standard fitting over the pipe. After cooling it was almost the perfect diameter.956. I sanded the ID very slightly and pushed the piston and seal in the PVS sleeve with a little moly I set it on the Diana tube and it popped right in. Thanks for your help so far, Lance

Felice Luftschein said...

For the 800, best thing is to check the Vintage airgun forum as I haven't disassembled one myself. I think there's details kicking around over there.

Good work on the seal!