Airgun Restoration

A lot of things aren't made like they used to be made. Airguns are a classic example of this. An old airgun, if taken care of properly, can last a long time. Unfortunately some of the internal components can deteriorate, over time, and make the airguns unable to hold air. Fortunately a "broken" airgun can be bought much cheaper than a working airgun, and the parts needed to fix them are not expensive. You just need to know how to take the airgun apart, replace the broken parts, and put everything back together.

In this Instructable, I will show you how I brought a Crosman 761XL back to life. This airgun was made sometime between 1972 and 1978.

Step 1: Tools and Materials

I bought a kit off of ebay, from a ebay store called UFIXITKITS.COM It cost 19.95 and came with online instructions.

The tools I used were:

A slotted screwdriver

A set of micro screwdrivers

Two pliers

A soft faced hammer

A wooden dowel

A 5/64" allen key

Some electrical tape

A paper clip

Some Q-tips, shop rags, and alcohol (for cleaning)

And some oil made for airguns.

Step 2: Right Side Screws

The right side is held on by three screws. Keep track of which screws were in which holes.

Step 3: Rear Stock Screw

The rear stock is held on by one screw. This screw stays in the rear stock.

Step 4: Bolt Knob

This step should probably be done first. Hindsight is 20/20. I wrapped the knob in electrical tape to protect it from the jaws of the pliers that I used to unscrew it from the bolt.

Step 5: Left Side Screws

There are two screws that hold the left side on.

Step 6: Take Off the Left and Right Sides

Carefully take off the left and right sides. There are small pieces that could fall out.

Step 7: Small Springs and Parts

There are a couple of small springs and parts that you need to keep track of. This is a good time to practice putting the pieces back together, while it is fresh on your mind.

Step 8: Remove the Barrel

There is a tiny set screw, in the barrel clamp that you need a 5/64" allen wrench to loosen. And a tiny slotted screw at the breach of the barrel. These screws would be very easy to loose, so put them somewhere safe.

Step 9: Air Gasket

This gasket is one of the pieces in the kit. The gasket is like a piece of plastic tube that sits on a metal piece, with a flange at the bottom. The metal piece is on the bottom (pump tube side), the plastic piece is on the top (barrel side). It is sandwiched between the bottom of the barrel and the top of the pump tube.

Step 10: Remove the Pump

The barrel band/pump tube cap is held in place with a split pin. A drift pin would be the best tool to remove the split pin, but I found that one of my mini screwdrivers fit perfectly and did the job of pushing out the split pin. Once the barrel band/pump tube cap is off, the pump can slide out the front end of the pump tube. The pump is held on the pump arm by a pin that just slips out.

Step 11: The Main Problem

The main problem with my airgun, was the end of the pump (the cup) was cracked. This made it so that the pump could not pump air to build up pressure necessary to fire the airgun. This is one of the pieces that comes in the kit.

Step 12: Remove the Hammer Assembly

The hammer assembly is in the back end of the pump tube. It is held in by a pin that can be easily pushed out. This pin has threads inside and these threads are engaged by two of the screws that hold the side plates together. The hammer assembly is three pieces

Step 13: Push Out the Valve Assembly

Using the wood dowel, Push the valve assembly out the front of the pump tube.

Step 14: Take Apart the Valve Assembly

There are two small pieces that will slip off the end of the main valve. Clean the main valve and then wrap it in electrical tape. Use two pliers to unscrew the two halves of the main valve. The main valve is brass and even though it is wrapped in electrical tape, you have to be careful to not use too much pressure on the pliers. Once the halves are apart, use a paperclip to push out the internal pieces.

Step 15: Clean the Inside of the Valve

I used the Q-tips and alcohol to clean the inside of the valve.

Step 16: Rebuild the Valve

Remove the old o-ring, clean the threads, and then replace the o-ring with a new one, from the kit. Return the clean internal pieces into the inside of the valve halves. After putting some oil on the o-ring, use the pliers to screw the two valve halves back together. Take off the protective electrical tape. Remove the o-ring from the end of the valve. Clean the valve. Replace the o-ring on the end of the valve. One of the small end pieces has two o-rings, one on the inside and one on the outside. Take both o-rings off and clean the piece. Replace the internal o-ring first. I had to use the stick of a Q-tip to make sure the internal o-ring was seated properly. Replace the outer o-ring and then put the end pieces back on the valve assembly.

Step 17: Clean the Pump Tube and Barrel

Before putting everything back together, now is a good time to clean the inside the pump tube and barrel. I used the wooden dowel to push a shop rag, soaked in alcohol, thru the pump tube a few times. I used a gun cleaning kit to clean the inside of the barrel. I also cleaned the insides of the side plates.

Step 18: Put the Valve Assembly Back in the Pump Tube

There are two holes, in the valve assembly that have to line up with two corresponding holes in the pump tube. Once you have the two holes lined up, apply oil to the outside of the valve assembly and then use the wooden dowel to push the valve assembly into place, inside the pump tube. Make sure the two holes line up.

Step 19: Put the Hammer Assembly Back in the Pump Tube

Put the three pieces of the hammer assembly back inside the pump tube and then reinsert the pin to hold them in place.

Step 20: New Pump Assembly

Install the new pump assembly by pushing the pin thru one end, onto the pump arm. Apply some oil to the pump cup, and then slide the pump assembly into the pump tube.

Step 21: Put the Barrel Band/Pump Tube Cap Back On

Put the barrel band/pump tube cap in the end of the pump tube. Line up the holes in the pump tube with the holes in the barrel band/pump tube cap and the pivot hole of the pump handle and push the split pin thru.

Step 22: Install the New Gasket

Install the new gasket that goes between the pump tube and the barrel. The metal piece goes on the pump tube side, the gasket goes on the barrel side. Both pieces are sandwiched between the barrel and the pump tube.

Step 23: Fasten the Barrel Back On

Use the two tiny screws to fasten the barrel back on. The set screw in the barrel band/pump tube cap and the slotted screw in the barrel breach.

Step 24: Reattach the Left Side

Make sure your valve assembly holes still line up and screw the left side plate back on, using the two screws, you took off the left side. You also need to make sure that the trigger sear is inserted into the bottom of the pump tube to engage the hammer assembly. And also make sure the bb detente is in place.

Step 25: Reattach the Right Side

Slide the bolt back into the breach of the barrel and then reattach the right side, using the three screws you took off the right side.

Step 26: Screw the Bolt Knob Back On

Carefully use the pliers to screw the bold knob back onto the bolt and then remove the protective electrical tape.

Step 27: Reattach the Stock

Tighten the screw to reattach the stock back on the airgun.

Step 28: Enjoy Your Airgun

For a couple hours of work, and about $20 of parts, you now have an airgun that will work like new again. Although the model I fixed was a Crosman 761XL, there are many models of old airguns that are worth bringing back to life. I highly recommend the kits from the ebay store UFIXITKITS.COM. Their kits are high quality at a reasonable price and their online instructions are clear pictures with concise text.

Step 29: Video

This is a long video, but I mainly made it so that I could reference it and make sure I was putting the pieces back together correctly.

As always, thank you for watching.