"YOU'VE COME A LONG WAY BB"

Rebuild Parts & Techniques


MKI or MKII Rebuid Kit;

http://www.mac1airgunshop.com/mkii-rebuild-kit-p/m1mkiikit.htm

 

It takes Heat to get these things apart most of the time. It will help you get the bolt, valve, and piercing group apart and back together if you use lots of heat to make the go loosen and the seals soften so you have a chance of getting them to let go.
Crosman Pellgumoil is often the culprit, in that it has transformed over the decades into something reassembling loctite threadlocker.
On lever type piercing assy the Nut to loosen is often so tight it requires a propane torch to get it to finally come unscrewed. The seal under the nut must be fried to the point of ash to get it out of there as it is rock hard and not willing to be removed more times than not.
Know your limitations and tool set and do not destroy the cap trying to rebuild it. There are people like me that can do it easy and to torment your skill set is not the way to go if you aren't profiecient in such things. It costs $15 to rebuild a cap.
It cost time and materiaL TO SAVE ONE that has been butchered AND THEY ARE NOT AVAILABLE.
There is a pry point on the valve that can be used by laying a very large driver across the inverted frame in the trigger area and then using a small flat driver to pull the lip of the valve forward using the large driver as a fulcrum. I never attempt this without first warming the action with a heat gun or propane torch. This makes it real easy to extract. If the seals are not soft from the heat it can be nearly impossible to remove valve. DON'T force anything.
All the surfaces contacting the orings must be free of scratches, debris or left over seal material. Make sure you don't put the valve in upside down as the Port must be UP.
The first time you charge the gun do it with the valve fitted and side screws tightened. I like to put blue loctite under the countersunk heads to eliminate any leakage past the frame/screw contact point.
Warm the frame before piercing the cartridge so there is never a chilled frame and seal attempting to seat for the first time. If the valve seeps slightly at first often a strike of the stem once will effect a seal.
If there are any irregularities to the valve seat the seal may not seal 100% and the seat may require cutting with piloted cutters.
If you look in the frame from the CO2 cartridge chamber you can see a small brass screen installed in the frame with a retainer. Make sure that screen is not got a hole in it as that will contaminate the valve group if that microscreen isn't intact.
As long as the rebuild is done debris free and the screen is good the parts should go for decades. DO NOT USE FIREARM LUBES ON AIRGUNS. Internal oiling should be very conservative and only done with Mac1 Secret Sauce. Lubrication needs in CO2 systems is very minor.
Rem Oil can be used for external wipe down rust inhibitor to keep steel parts from corroding.
The leaf spring on the trigger guard can be bent down away from the Sear to reduce drag on the hammer and increase velocity slightly. It also improves the trigger feel if you lube the end of the leaf spring with grease where it contacts the sear.

To degas gun when it is low you can put both thumbs behind the grip and both forefingers over the cocking knobs and pull rearward firmly with the gun un-cocked. If it isn't low on CO2 it is difficult to degas and should be shot down till it is low.
Make sure that you always leave the gun charged at least with a little gas.  Only leave them empty of CO2 when they see extreme heat conditions.
Never expose to direct sunlight or heat in excess of 120 degrees F for extended durations. When you do charge it up with a new cartridge make sure you open the bolt and cock the gun first. When you run low on your last cartridge don't shoot it all the way down.
Gun should be stored with bolt open, gun charged but not loaded or cocked.

Trigger adjustment for MKI & II
Screw in sear forward of the trigger blade is turned clockwise for sweeter trigger. To set trigger cock gun to the high power setting with open bolt. Turn sear adjust screw until the hammer clicks off high power. Back screw out 1/8th turn and make certain the thing is cocking firmly. If the gun won't go to the high power
setting in the first place back off the screw adjust until it does. Then start adjust procedure above.

Power adjustment for MKI & II (all early models and most late LD's have the power adjustment). The screw on the front of the housing below the barrel is the adjustment for power. Clockwise turns power up. If an alternate spring or hammer spacer has been employed you must be certain that the gun will still cock to high power when turning up the power. If you turn in too much it could fail to catch the high power setting. The tension of this spring affects the high and low power performances.
If someone has altered the trigger return spring or the sear engagement spring it could result in the gun only cocking to one power setting or the other. Not enough trigger blade return spring and you lose low power mode. Not enough sear engagement spring and the gun won't cock to high power. This trigger can be set for about 1 lb. without any modification at all. Simply by adjusting and lubing. It is a simple but elegant design and one of the finest triggers ever produced on a budget airpistol.
Enjoy your pistol and thank you for the business. It is IMO the finest CO2 gun ever produced.

 

S&W CO2 Pistols 78 & 79, Daisy 41, 780 & 790 Kit;

http://www.mac1airgunshop.com/smith-wesson-rebuild-kit-for-co2-pistols-p/sw78kit.htm

 

The S&W has an adjuster for power on the front below the muzzle. You need to take the adjuster assembly out of the frame to allow the hammer adjustment plunger and tube to slip out the front of the frame. This is how the front is held together. Don’t try to remove the upper housing from the lower without first getting these two parts out. Heat will always coax parts to move when they are stuck together with old lube goo. Pellgunoil resembles Loctite after a few decades and needs to be wire brushed off all surfaces it has adhered to. Getting all the residual grease and lubes cleaned out is paramount TO A CORRECT REPAIR.
All the surfaces contacting the exhaust seal and o-rings must be free of scratches, debris or left over seal material. The Hard seals we use demand clean and scratch free points of contact and need to be lubed with DC111 or divers grease on assembly.

Getting the Piercing cap apart will also be a challenge without the proper seal picks and HEAT to get thing to release and come apart. DO NOT START DRIVING CROSSPINS OUT! You take the seal retainer out and use a seal pick to drag the seal out of the groove. The rest of the cap does not need to come apart.
The first time you charge the gun do it with the valve fitted and side screws tightened. I like to put blue loctite under the countersunk heads to eliminate any leakage past the frame/screw contact point.
Warm the frame before piercing the cartridge so there is never a chilled frame and seal attempting to seat for the first time. If the valve seeps slightly at first often a strike of the stem once will affect a seal.
If there are any irregularities to the valve seat the seal may not seal 100% and the seat may require cutting with piloted cutters.
If you look in the frame from the top with no valve fitted you can see a small brass screen installed in the frame just sitting under the Transfer tube that brings the gas from the frame to valve. Make sure that screen has not got a hole in it as that will contaminate the valve group if that micro-screen isn't intact.
As long as the rebuild is done debris free and the screen is good the parts should go for decades.

DO NOT USE FIREARM LUBES IN AIRGUNS. Internal oiling should be very conservative and only done with Mac1 Secret Sauce. Lubrication needs in CO2 systems is very minor.
Rem Oil can be used for external wipe down rust inhibitor to keep steel parts from corroding.
It improves the trigger feel if you lube the engagement point with moly grease where it contacts the hammer and slacken the tension slightly to reduce hammer drag and trigger pull weight. On Trigger adjust models run the adjustment intill it fires off high power then turn it back out ¼ turn for safe engagement.
To degas gun when it is low you can put both thumbs behind the grip and both forefingers over the cocking knobs and pull rearward firmly with the gun un-cocked. If it isn't low on CO2 it is difficult to degas and should be shot down till it is low.
Make sure that you always leave the gun charged at least with a little gas.  Only leave them empty of CO2 when they see extreme heat conditions.
Never expose to direct sunlight or heat in excess of 120 degrees F for extended durations. When you do charge it up with a new cartridge make sure you open the bolt and cock the gun first. When you run low on your last cartridge don't shoot it all the way down.
Gun should be stored with bolt open, gun charged but not loaded or cocked.

 

Izzy 46M Valve Upgrade Kit;

http://www.mac1airgunshop.com/izh-46-valve-upgrade-kit-p/miz46ss90.htm

We have been making this seal change now for over a decade on the quality Russian Match AirPistol and we have not seen any hiccups yet. It seems like this pistol will work forever with this 90 durometer seal upgrade kit when kept wet with the Secret Sauce. The Kit includes seals, Mac1 Secret Sauce and a Stainless Steel valve chamber designed to be a replacement for the original. Take the old chamber and seal out, replace the original factory seal with the thick then  thin 90 durometer o-rings, install the stainless chamber bevel forward and reassemble gun. This can be done from the front end once the grip, cross pin, front sight, barrel support, pump lever/piston and cocking links are removed. We saw many guns in 2009-10 arrive from Russia as new stock that had been sitting for up to a year in storage. About 10% of the new guns leaked straight from the Box which prompted Me to manufacture the 300 series Stainless Chamber to nix the possibility of magnetic draw to metal particles or surface corrosion.
HEAT is highly recommended to get the Tube to unscrew from the Receiver. You need to be creative and handy to do this".

If the kit does not get the job done it is normally a tube or exhaust pin that is corroded or grooved at the seal. Tube damage is semi terminal but exhaust pin service is a more extensive repair that requires the mechanism back end to be removed and serviced.

Gun should be stored with latch slightly open, but not cocked or pumnped. Kit includes a bottle of Mac1 secret Sauce to keep the pivots seals wet.

 

Valve Stem rebuild Kits MKI;

http://www.mac1airgunshop.com/smith-wesson-rebuild-kit-for-co2-pistols-p/crmkistki.htm

This kit includes the brass head and seal as well as a return spring. The steel stem is not included and the Factory part is reused.

Valve Stem Rebuild components for Professional Rebuild of the Crosman MKI Exhaust valve Assembly. Can be used to fit many other models and other makers. Can rebuild the Crosman 454, 1600, 500, SA6, 44 and Hahn 45 It is not a copy of the Original Factory Part. For that reason we use a different valve spring with this head which is included in the kit. We use 100% Polyurethane seals so our guns DON'T Leak. Made in USA by Mac1.

A propane torch can be very helpful to get the brass head to separate from the steel stem. We use a .25” hole in a recess the size of the brass piece so you can drive the steel stem out of the brass head. The new seal fits in the new brass head and you use a 1/8" hole in an anvil to drive the head and seal onto the stem. It is a good policy to use a permanent thread locker in the brass head for insurance. Once the head is pressed together it can be trued and faced off to ready it for use. We face it off in the lathe after truing the stem so it runs concentric. Heat the entire gun up to toasty when you first charge it so the seals will be supple and the pressure will be high. Making sure there is no damage to the valve seat where the seal sits is very important as the Mac1 seals are hard enough so you can leave the gun charged all the time. Getting it to seal initially can be impossible if there is any seat irregularity. Polishing the seat is often required to remove any scratches or abuse.
Because of minimal Valve return spring tension it is appropriate to cock gun before charging when using this valve and spring. It will give far better consistency and power but the valve can be held open by the hammer tension when the gun is NOT cocked so it is important to cock before charging.
If you use the parts that make for the most reliable repairs imaginable a DIY project can be the best investment you ever made in an airgun. Quality parts last. Your time is wasted when you use inferior parts.

 

160 Stem Kit; Also fits 180, 187, 150, 157, 400, 166 and Sears Models

http://www.mac1airgunshop.com/smith-wesson-rebuild-kit-for-co2-pistols-p/cr160stki.htm

This kit includes the brass head and seal . The steel stem is not included and the Factory part is reused.

We use 100% Polyurethane seals so our guns DON'T Leak. Made in USA by Mac1.

A propane torch can be very helpful to get the brass head to separate from the steel stem. We use a .25” hole in a recess the size of the brass piece so you can drive the steel stem out of the brass head. The new seal fits in the new brass head and you use a 1/8" hole in an anvil to drive the head and seal onto the stem. It is a good policy to use a permanent thread locker in the brass head for insurance. Once the head is pressed together it can be trued and faced off to ready it for use. We face it off in the lathe after truing the stem so it runs concentric.

It is always appropriate to leave your bolt open when charging a CO2 gun.
Heat the entire gun up to toasty when you first charge it so the seals will be supple and the pressure will be high. Making sure there is no damage to the valve seat where the seal sits. It is very important as the Mac1 seals are hard enough so you can leave the gun charged all the time. Getting it to seal initially can be impossible if there is any seat irregularity. Polishing the seat is often required to remove any scratches or abuse. If you use the parts that make for the most reliable repairs imaginable a DIY project can be the best investment you ever made in an airgun. Quality parts last. Your time is wasted when you use inferior parts.


600 Valve Stem rebuild Kit; Same Instructions as the 160 stem kit

http://www.mac1airgunshop.com/smith-wesson-rebuild-kit-for-co2-pistols-p/cr600stki.htm

 

622 Valve Stem Rebuild Kit;

http://www.mac1airgunshop.com/smith-wesson-rebuild-kit-for-co2-pistols-p/cr622stki.htm

Complete Valve Stem Rebuild components for Professional Rebuild of the Crosman 622 Exhaust valve Assembly. Not an exact copy but works great. We use 100% Polyurethane seals so our guns DON'T Leak. Made in USA by Mac1.  A propane torch can be very helpful to get the brass head to separate from the steel stem and later models need the head drilled out to push the stem out. The seal fits in the brass head and you use a 1/8" hole in a anvil to drive the head onto the stem. It is a good policy to use a permanent thread locker in the brass head for insurance. Once the head is pressed together it can be trued and faced off to ready it for use. Heat the entire gun up to toasty when you first charge it so the seals will be supple and the pressure will be high. Making sure there is no damage to the valve seat where the seal sits is very important as the Mac1 seals are hard enough so you can leave the gun charged all the time. Getting it to seal initially can be impossible if there is any seat irregularity. Polishing the seat is often required to remove any scratches or abuse.
If you use the parts that make for the most reliable repairs imaginable a DIY project can be the best investment you ever made in an airgun. Quality parts last. This kit is the brass head and seal only. It is not a replica of the factory head but gives more valve volume and flow for more power.
The 622 needs a hole drilled in a specific spot as shown in the picture. With a 1/8" spring pin driven into the strategically positioned hole, the 622 valve and tube will never separate again. Planned failure cancelled with one hole drilled. Go to the Product link and there is a picture of a tube drilled and pinned.

 

Flat Head Piston Rebuild Kit;

http://www.mac1airgunshop.com/flat-head-piston-for-early-crosmans-p/mflhereki.htm

This kit is perfect for rebuilding the pistons on all the old Crosmans. It fits S&W 77A piston as well. It presses onto the ones like the 760, 130, 140 and screws onto the 101, 120, 105 etc. It fits virtually every flat top piston Crosman ever made. All the DIY needs to do is extract the cup, brass piece and aluminum washer and press the plastic piston head on in place of those parts. Leave the felt on. The piston length will need to be shortened a few threads in most cases for it to fit. Well within the adjustment range.

Mac1 manufactured in USA. Black or grey plastic head, Uses a #111 90 Durometer Urethane seal as the Pump seal. Piston Head Comes with a spare oring.This replaces the factory aluminum washer, brass pressed on part and the Pump Cup. Take those off and press this on. The best DIY solution going and the pros use it also.

The kit comes with two #111 90 durometer urethane o-rings so you have a spare for the piston or you can use it on the outside of the valve.

 

Stainless Steel Adjustable Piston Head;

http://www.mac1airgunshop.com/steroid-stainless-steel-piston-head-p/mststpihe.htm

 

Mac1 made in USA. This 300 series Stainless Steel Solid Piston Head is non-magnetic and rust proof. The best part for upgrading your Sheridan piston for strength and adjustability. You need to cut the factory piston head off, thread the rod end to 1/4X28TPI and install the supplied Jam nut. You are piston adjustable and bullet proof. Mac1 Steroid Piston Head includes the Factory Pump Cup. (OAL) Length of adjusted piston is 7.25".  This solid head will not flex and is compatible with the factory pump cup. It also fits the very early Pistons that had a non-rebuildable head on them. You can remove the factory head and screw these on as a direct replacement on models with threaded rod ends. A part like this is needed when you have a gun that will last practically forever.

 

Sheridan Rebuild Kit-Keyed Rivet or Round Rivet;

http://www.mac1airgunshop.com/product-p/mshrekikr.htm

http://www.mac1airgunshop.com/product-p/mshkirr.htm

I don't sell valve tools. Bryan & Associates does.
Guns either don't pump at all, only retain one pump (blows pump back open) OR leak out the exhaust side. If it doesn't pump at all often it only needs a pump cup. When they are oil starved they fry relatively quickly for a part that could go 100,000 rounds or a MILLION PUMPS lubed with the Sauce.

I have made all the parts the factory has discontinued in the course of the Crosman takeover of the Benj/Sher Badges. So I can still make them last like they always did.
This company (Sheridan/Benjamin) made guns that lasted for 40 years. It was cheaper to buy the badges than to compete with them so Crosman bought the company and immediately cheapened the products quality and raised the price $30 so they could improve the margins.
I build Billet pump arms that are the best levers ever so we can use those on the old guns & current offerings. The Billet lever can be fitted to early guns but they don't NEED it like the current gun does. The Lever in the Rocker gun was the very first part Crosman discontinued and then the subsequent part was drastically cheapened to make it weak by design so it would fail when pushed.

The currently available factory parts are rubbish compared to most 70-80's vintage components still in the guns. If I were to do a NORMAL In House valve job($75) I would fit spares pulled from guns with low use that were in for my Steroid Upgrade. 90% of what I do is make guns High Performance(Steroid) and I take out perfectly good 80's spares so I can do Standard valve jobs on the other 10% of the guns I work on.  "if she works WAIT till she doesn't".  Sorry I don't sell take-outs, What you get in the kit is the best of the current stuff. Don';t leave those with more than one pump in them when in storage.
The key point is the Repair kit exhaust valve should not be used unless the Exhaust valve in the gun has failed or looks to be tired. Most Rockers go down because of an Inlet seal failure (weak link)and that is the only part you really need to change other than the other soft goods & pivots.

Test the power. If it does not leak and dumps all its air (with 8 pumps) the best thing to do is put fresh parts in the front of the gun. New Cup, new link pivot to piston, new keyed or round rivet, fresh front spring pin(make sure it holds good OR replace front plug($25). This will eliminate all the front end excess head space. Mop the goo out good (sock on a dowel) before you reinstall lever and piston group or you will push it(goo) into the valve group. This snot needs to be cleaned out not pushed through the gun.
The weak link in this system is the factory check valve. It wants to blow and will go first if the gun is pushed too hard or the lube gets put directly in the air hole. Then it instantly becomes a single pumper and will no longer build beyond one pump of pressure.
 6 digit Serial Numbers on the 200K plus all have keyed rivets if they are original. Before that is round rivet as a rule. Open the lever and look at the rivet that connects the lever arm to the lever link. If it is round on both sides(small on one side) then that is the round rivet. The kit has three factory parts(cup, front pin & Exhaust valve. The other six parts are Mac1. Two PTFE gaskets to take the front gasket and leads place. Link pin, rivet, inlet and bolt oring are all Mac1 Steroid Upgraded components. 9 Parts total. Get the Secret Sauce. ($4 for 2oz or $10 for 10 oz).
The kit I sell($25) comes with my Check valve and the Factory Exhaust. Unless the Exhaust seal is bad in yours it is more than likely a much better choice to reuse than to put the current stuff in. My Check valve(inlet) is the best ever. Hit it good to seat it with X visible. Use a solid drift just smaller in diameter than the check valve and strike it good so it is smashed into the seat. Make sure you are not trapping any debris when you do this. Cleaning the thing out is the key to a quality job. I soak it for weeks before I attempt to remove the crud. Some guns are completely impacted with debris as they were NEVER LUBED and consequently never cleaned themselves. They go down because of corrosive and/or congestive debris.
Get the secret sauce($4). It eliminates any future lever or pivot wear unless you abuse the gun by running it oil starved.
MOST important. All the Sheridans with the Spring steel rear sight set on wedges will eventually pop the solder joint loose between the Tube and Barrel. You must remove it immediately so the stress over time thing is stopped. I stretch it out and reinstall for the iron sight fans or you can glue it on and eliminate any possibility of solder joint failure while also being able to line the rear sight up with the direction of the front sight.
Williams peep was retooled last year(2012) to fix any issues with sighting in on the current guns. Unless you buy from someone with two year old stock you will get a revised one but the 80's and before  vintage gun would work with the earlier 5DSH Williams with no alteration. The current sight gives you more adjustment than ever and will work on both early and late guns. $40. Drill and tap for the Williams peep is $10 and is required on all models prior to 1986.
I'm always afraid of giving advice to DIY's on Dan repairs because I have seen so many actions screwed up in my time working on these. Make sure there are no nicks in the exhaust valve guide where the seal or gaskets sit. Try to make sure you get as much of the lead out of the valve nut threads as possible. It is too easy to cross thread the nut with the multi-tool. It is very important to turn it backwards till it picks up the first thread. If it doesn't feel right it propably isn't. Don't thrash the thing. I have a guided tap to fix jacked up threads. You must give me some material to work with so if you get the nut in there sideways please punt while I can still return you a functional piece.
Packing with the multi tool can be a challenge even for the best DIY so it is something not everyone will be able to accomplish. If you get over your head there are pros that can take the gun and still fix it.
Make sure you get all the old seals out of there. The front gasket can be a real challenge if it stays inside. Cleaning the snot out of the barrel, tube and valve is the key to a proper rebuild. I spend more time doing that than building the gun.
The oiling design element of all Dans and Benjamins seems lost on most people. The end of the piston where the link hooks up is either a porous metal part or one with a felt. That felt/part should always be saturated moist and delivering a film of lube to the pump tube ever stroke. You lube the pivots each with two drops at the rivet AND FRONT PIVOT BUT AT THE PISTON PIVOT GIVE IT 6-8 drops SO THE PISTON IS ALWAYS WET VISIBLY.
This insures enough lubricant is fed to the gun so the atmospheric contaminants & moisture can be carried through the gun and out with the discharged air. That is how the guns stays clean inside. Secret Sauce lubricant will eliminate wear and facilitate the internal cleaning when used on the Pump Pivots. You do not need to put it anywhere else as it is blowing through the system and will take care of everything if you keep the guide end of the piston wet.
Good Luck rebuilding your gun.