We start by removing the scope & mount (If you have one)
Then remove the front screw of the trigger guard.
To separate the stock from the receiver start by removing the top screw....
The stock comes off....
We need to remove the cocking lever to gain access to the release pins, so we need to remove these 2 lock-washers.
The pins come out easily once the lock-washers are removed.
Make sure these washers come back to the same spot, or the coking lever will have slack...
Remove the linkage with an allen wrench, this single screw releases the piston assembly.
Once the screw is out, the arm releases easily.
Here we’re going to remove the 2 side pins that hold the trigger assembly and spring, use a small punch and tap lightly to push the pins, at this point the spring tension is minimal, point the receiver down and use some rags to cushion the assembly when it comes out.
Pull your assembly, spring and guides out...
The power plant slides out easily....
The piston comes out easily, this is the heart and soul of your Diana 48...
We’re going to need a flat screw-driver to remove the old rubber seal, just be careful not to score or scratch anything...
This is a new JM seal, made of hard rubber and it will give you a really hard time to seat it in the piston... I warmed the seal in the microwave oven for about 10 seconds, just enough for it to become flexible. Just be very careful not to overheat and deform the seal, as some ovens have a lot of power. Push the warm seal in the piston’s seat and will fit in easily, the seal will harden again, as it gradually cools down.
Apply the JM “heavy tar” to spring only, this should be the last step as you’re getting ready to reassemble all your parts back on to the rifle.
We installed the spring by pushing down with a piece of a 2x4, once the the two holes lined up, I simply inserted a small punch to retain the position. Then I inserted a pin by hand and drove in by taping it lightly with a small hammer, then I removed the punch and the other pin went in much easier.
I highly recommend treating the two stock screws with Locktite or Permatex compound, keeping these screws from shaking loose will insure accuracy.
Right after I reassembled my rifle, I went to my backyard to test it, the rifle cocked smoothly and it had a more solid sound when it fired, I was very pleased with the result.
Tools needed:
Small punch, small hammer, phillips screw-driver a piece of wood (2x4)
Level of Difficulty: (1-10) I rate this project as a: 6
This upgrade requires a James Maccari tune kit and is highly recommended for all users.
This is a group of 8 shots at 15 yards...