Replace main seals in Diana/Original Model 6, 6G, 6M

Lift and slide out the cocking slide.


Using a wooden probe on the pinion gear teeth start to extract the main piston. You will have to jiggle the sear lever at times to get the piston past it. Towards the end you will be able to pull it through with an index finger.

If you prefer you can remove the sear spring and the sear arm should lift out thus you don't need to depress it to let the piston past. I found this out much later when reading another airgun blog so I have no pics!



This shows the sorry state of the washer. Oil contamination degraded the brown seals over time. The new blue replacements should not have this problem.
Remove remnants from the end of the compression chamber using a wooden stick followed by a vacuum cleaner hose with a ten inch length of garden hose taped into the end of it.


Clean up the piston and with a downwards and slightly sidewards pressure slip the dovetailed spigot into the hole in the new washer on a clean hard surface.


Before reassembly ensure there are no burrs or sharp arrises which could shave the new washer on reassembly. Clean out any debris from the pistol with paraffin (kerosene) and dry thoroughly.

Keep the pins, springs and screws in a safe place such as a tin can.