Idiots guide to classic airgun strips (pt 1)

[Phil Russell]

I forgot I had written these notes: they may help. All is pretty straightforward except getting the trigger / safety back together which is a bit of a fiddle until you get the knack. All is explained here:

CROSMAN 766 STRIP

Taking apart.
Remove barrel band (2 halves, single small screw goes though band)

Remove barrel band ends: plastic, lifts away.

Knock out the pin holding the pump lever to the pump tube.

Remove pump lever with pump attached.

Remove barrel: hex key on top of action.

With the breech block on its side, screws uppermost, stock to the right, remove the 4 screws. Keep top plate in position while doing this.

Gently prise the top plate off the bottom plate. Take care the pump handle plastic grip holder, black plastic sprung laden bit on left, does not ping out as you release the top plate. Top plate may come away with the trigger and safety catch or may leave trigger and safety in the bottom plate. Either way the trigger safety spring may become detached from its location on the safety. Do not worry. Remove trigger, spring and trigger pin.

Note position of trigger sear components.

Lift sear away, taking care not to lose the large spring that acts on the sear bar. Lift off the long spring and plastic peg that acts as the BB follower from its channel.

The valve housing is held by a screw to the left of the valve housing. Before releasing this, note the brass component at the top of the valve body towards the left. This has a small spring over it. Release and remove the screw holding the valve housing but hold the housing in position. Now gently lift the housing away to the right, catching the small spring on the brass piece and also noting that the striker piece and a black plastic end body will be released under spring pressure on the right hand side. Just go slowly and this component will not be forcibly ejected. The brass valve body will slide out of the air cylinder. If it is an easy, loose slide then inspect the O ring as it will most likely be worn.

If needed, replace O ring.

Clean all parts, especially the air cylinder.

I have not dismantled the valve.

Rebuilding
Reversal of above but these tricks may help.

Assemble valve body and housing into place in the air cylinder. Have the brass component in place but do not fit spring yet. Take care that the striker and its spring and the black plastic end cap are located correctly. Replace the screw to hold the valve housing.

Carefully replace the small spring over the brass component. There is just enough room to wiggle this over the component; it stays in place against the bottom plate.

Refit trigger sears in place and slip the sear spring into place.

Refit the pump handle retaining spring and catch ... take care it has a habit of falling out.

Refit the trigger and its rod with the safety spring under the trigger and the hooked end pointing up. At this stage I found it best to hook a small bit of thin wire over the long arm of the spring and feed it towards the trigger such that when the top plate is replaced it protrudes out of the trigger guard.

Replace top plate: a bit fiddly to do this and keep pump handle spring in place but persevere.

When located, pull on the bit of wire to pull the safety spring long leg downwards ... look through the hole for the safety catch to see if it has cleared the hole. When it has, feed the safety catch back into place and release the spring. Pull the bit of wire out.

Replace 4 plate screws.

Refit barrel, and pump etc.

Job done.

Cheers, Phil

[ggggr]

I got this the other day and thought I would do a strip down. Remove rearsight if you want. Remove the front and rear stock screws ,the trigger guard screw and the trigger guard and lift the action from the stock. To be able to remove the barrel and cocking arm, you will have to drift out the small pin in the housing the cocking arm passes through. Undo the barrel pivot lock nut and undo the pivot bolt and remove the barrel. If the breech seal needs changing then do it now. Remove the endcap from the cylinder. Unhook the trigger spring off the tang on the cylinder/trigger sleeve. Knock out the trigger pivot pin (front one of the two pins) and remove the trigger. Using the bit of forked tube tool ( mentioned early on in the guides) or similar keep pressure on the sleeve and knock out the 2nd pin. (I managed to hold the pressure with just my bare hands but use the tool just in case). Release pressure and the tube should come out,followed by a washer and the spring guide. Remove the spring and the piston. Clean everything up and lube. The example I got had no piston seal. It think it should be a synthetic seal held on by a metric screw (3mm I think). I made up a leather one to replace it. Replace the piston,mainspring,guide,washer and sleeve and compress with the tool to enable you to get the rear pin through the cylinder. Go to pt 2

[ggggr]

Enter the trigger into the housing and line up the holes with a punch and replace the trigger pivot pin. Refit the trigger spring onto the pip at the rear of the trigger and the tang on the housing. Replace cylinder end cap. Slide cocking arm through its housing an locate it. I would screw the barel pivot home now to hold everything in place while you refit the pin in the cocking arm housing. Replace the barrel pivot bolt lock nut. Replace action in stock and refit the stock bolts and trigger guard. Replace your rear sight.
I was surprised that this gun is the same size as the Diana/Milbro 22/23/76 and Webley junior/jaguar/ranger. Apart from the sights being better than the other guns mentioned, I did not think it was much better made. The weak point on the other (non tinplate) guns is the piston can wear at the point the cocking arm pushes on. The Hw25 piston did not seem much better made. Obviously the hw has decent scope grooves but unless you are intent on paying £140 + for a new gun, I dont think the hw justifies the extra money as a starter gun over the other guns mentioned. It seems to plink ok but then so do the others. It,s a pity some of our engineers on here have not made up a better piston to fit the Diana/webley range of small rifles.

[ggggr]

If you want to take off the sights then the rear is held by the elevation wheel and a screw at the front of the spring steel plate. The front sight (early model I guess) is alloy. You will need to undo and remove the small screw on the side that nips it up and then tap it off the barrel. Remove the two front stock screw and the 2 rear ones on the trigger guard and lift the action out of the stock and remove the plastic end cap. The cocking arm can be lifted out of the slot in the cylinder but remain connected to the breech block. Undo the barrel pivot screw and remove the barrel. Watch out for the plastic washers on either side of the breech block. If you want to clean and lube the plunger and spring, do it now. You need to knock the small tube that passes through the breech block with a punch. As you withdraw the punch the plunger and spring should fly out. Clean and lube and replace them and refit the tube and the 2 plastic washers. You will need a 10mm spanner to undo the stock nut/trigger nut from the captive bolt that passes through from the inside of the cylinder. Look how the trigger spring goes (one leg behind the trigger and the other pushing against the inside of the cylinder. Undo the nut and remove the trigger set up and the captive bolt. Go to pt2

[ggggr]

Use your special tool bit of forked tube (read first few posts in the guide) and compress the mainspring and remove the cylinder pin and then ease the tension and remove the gude,mainspring and piston. The piston set up on the one done was a leather washer with a plastic buffer in the centre and also a spacer underneath. It was held on by a small screw. If the leather washer is damaged, you can make one up. if the rest is damaged then I would buy new. Clean and lube everything up and refit the washer set up to the piston. Fit the piston, followed by the mainspring and guide. Compress the spring and refit the cylinder pin. Put the captive bolt through from the inside of the piston and refit the trigger housing (making sure the trigger spring is in the right position, with one leg behind the trigger and the other in the cylinder) and nip up the stock nut/trigger nut. Refit the plastic end cap. Refit the breech block and the barrel pivot bolt.Locate the cocking arm in its slot in the cylinder. Put the action in the stock and refit the trigger guard and stock bolts. Refit the sights and dont forget to nip up the small screw on the side of the foresight.

[ggggr]

I would not attempt this until you have done a few guns. It is fairly simple in design but the trigger pins are a swine to get out and there are a few other things. I will say that if you make up a couple of long slave pins for for fitting the cylinder end pin and sear pin + a short one to hold the barrel plunger while you attempt to refit that, you will make things easier for yourself. A dremel might help to ease the trigger pins rather than trying to move them a bit and file them ( like I did). If you have taken notice of this we will begin.
You can remove the rearsight adjuster screw if you want and the little sprung pin and spring that locate it. Remove the 2 side stock screws, the long one through the pistol grip and the trigger guard screw. The trigger guard should lift off and the action should come out of the frame. The long middle sear does not need to come out but everything else does. The sear spring has a small piece that sits on it at one end and a tang on the cylinder at the other. You could try to compress it and get it off but I would do it like this. Knock out the front of the 2 pins in the cylinder (holds the sear) and as you withdraw the punch, keep pressure on the sear until the punch is out. Slowly release the pressure on the sear and it should come away from the spring and the small piece (be VERY careful as this could fly for miles, which is why I suggest doing it this way). When the sear is out you will see a small pin coming out of the end cap into the cylinder. Remove this with tweezers. It is the pin the trigger adjuster screw pushes against. Now knock out the rear of the 2 cylinder pins and keep pressure on the end cap as you remove the punch. The endcap,sleeve and mainspring guide and mainspring should now come out. Now remove the trigger pivot pin. Notice how the short leg of its spring sits in it and the long leg pushes against cocking arm retaining pin above it. Remove trigger and spring. Knock out the cocking arm retaining pin. Break the barrel and knock out its pivot pin. Watch out for the barrel plunger pin and spring flying. You should now be able to lift the cocking arm out of the cylinder and remove the barrel. There is a plunger and spring on the cylinder as well, held by a grub screw underneath. Undo the screw and remove the plunger and spring and clean,lube and replace now. The piston should come out of the cylinder . It has a leather washer with a fibre buffer, held by a small screw. Clean off and lube all the bits and get ready to put back together. Replace the piston in the cylinder and then locate the cocking arm. Replace the cocking arm retaining pin and then locate the barrel with it plunger and spring in the breech jaws. A short slave pin really would help! Replace barrel pivot pin. Go to Pt2

[ggggr]

Now replace the mainspring,guide and sleeve in the cylinder. I used a socket to push on the sleeve and then put a pin through the sear pivot hole in the cylinder. With this holding things in place you can replace the endcap and push its pin through ( then remove the pin from the sear pivot hole). Replace the trigger and its spring, making sure the long leg of the spring pushes against the cocking arm retaining pin,then fit the trigger pivot pin. Get your tweezers out and replace the small trigger adjusting pin into its hole in the endcap. Heres the tricky bit You now need to replace the sear and its spring and that small piece that locates on the tang on the cylinder. I would reverse the way you got it out. Get the sear,spring and small piece somewhere near and then locate the small piece on the tang on the cylinder. Keeping pressure on you should be able to locate the sear and replace its pivot. Replace the small spring and pin that locate the rearsight adjuster and refit the adjuster. Put action in frame and replace trigger guard and its screw,the 2 side screws and the one through the pistol grip.
On mine the trigger travel adjusting screw was stiff so I put some plusgas on it while the gun was apart. You wind it in to reduce travel but it does not need to come out for the strip. On my gun I noticed the mainspring was quite small in diameter( I was expecting one like the Original model 5). I thought about fitting a larger diameter one that was shorter but left that for another day. The spring in the gun was a bit worn but the power is not bad now made up a piston washer. The trigger is heavyish and would benefit from some work but the pistol is fine for plinking. I dont have a chrono but would say it,s more powerful than a Webley but less than a Scorpion. The rearsight is not the best but it is a fairly fun plinker. I shoot two handed. The foresight does dig into your hand a bit when cocking. A strange gun this Ugly and beautiful----Well made but with some chimpanzee touches