Here is what I found when I opened the action tube.

The rear seal had turned to powder.

Partially disassembled trigger assembly.

Most of the front piston was welded to the bottom of the compression tube. I chipped it out with a hollow brass cleaning rod. Then I cleaned it up with a disk brake caliper hone.

All the old grease and rust had to be removed completely.

The rack gears had to be surgically clean.

The rear piston hub being cleaned.

The action tube screw on/off cap.

The rear seal dovetail that twists and locks into the rear piston.

A heavy spring washer takes up the side to side slack in the barrel.

This gun has a locking lever to hold the breech shut.

It's getting cleaner.

I disassemble, clean, polish and lube every single part of a gun. These are spring washers that hold the breech shut when the locking lever is closed. They were not installed properly. They must be placed in opposite directions so they will spring apart.

This is what I found behind the breech seal.

Someone with very little patience had worked on this gun before.


Something must have come loose inside the action before the other guy worked on this gun.

Maccari still makes seals and springs for these guns.

Everything went back together smoothly. The two piston "GISS System" action lets the gun fire with absolutely no shock whatsoever. I thought the gun never fired the first time I shot it. All I heard was a click. I opened the barrel to see if the pellet was still in the breech. Then I looked to see if it was lodged inside the barrel. Turns out everything worked just right the first time. This is an amazing (and very complicated) gun.
Rob

I take it you've worked on these before? I have a 1978 75 which will need the pink seals replaced but I am not going to even attempt to lay all ten thumbs on it. If there are three moving parts, I will misplace/lose two. That many? Looks like the hardware section of Home Depot! Great job, BTW!

What does the entire gun look like? Man, when ever I see that someone has taken a hammer to a gun I just get the urge to start slapping someone!

Roy,

Keep the change

Rebuilding my 75 was a fun learning experience. Once you sucessfully get a GISS back together, no other springer rebuild can look challenging.

To me, airguns are just another machine.
I completely rebuilt a Mitsubishi robot in five hours last week. I'd never worked on one like it before either. Hooked it up, homed it and it's still running. If it moves or uses electricity, I've worked on it in one form or another.
Now how do I set this alarm clock???!!!
Rob

Hey Rob, that was one hell of a job!! That was certainly a lesson on patience. Great pictures and details of the job. It makes an RWS look like childs play. Thanks - Lee

He was very pleased. I was formerly owned by a friend of his. I was glad to help him out.
Rob

your were owned? that friend an X-wife?

Are you drunk?

IT was owned by a friend of his.
Where's the EDIT link?
Sorry.
Rob