2015 marks our 35 years of Gunsmithing Service and 10 years Airgunsmith has been providing quality parts and service online to airgun hobbyist and professionals world wide

 

 

 



 

Crosman MK 1 & MK 2 Parts & Repair Service


 

Airgunsmith Now Offers MK1 & MK2 Teflon Stem Seals  in both type one and type 2

See Airgunsmith MK Teflon Seals

 


Complete Crosman Mark I & II Rebuild
Turn around time on the Crosman Mark I & Mark II is 1 to 2 week




Complete Mark 1 & 2 Rebuild includes
-----------------
Complete disassembly cleaning and re-assembly
with all new seals including new valve stem seal

Crosman Mark  I & II Rebuild Kits
Kits include All O-rings needed
Plus New Valve Stem Seal & Airgun Oil



These are the same seals we have been using in our MK I & II rebuilding for the last 10 years

We need to know the valve stem seal you need
use link below to determine your seal type
 

Airgunsmith MK Seals Type



 

Even though this seal looks like its in good condition, its hard as rock.
 


The Square shape of the valve stem
 is what keeps the stem centered

 


This seal can be removed with heat,
when the seal is warmed it will become pliable
 



After removing the pesky valve stem the work begins
A variable speed tool with a dental bit is ideal for this pesky work.

Heat is the easiest way to remove
the seal, I don't like fire in the shop so the leister comes into play, it heats to about 1300 degrees, that is enough to soften the valve stem seal and to make separating the valve stem from the valve easier.

Either way works my little grinder is always at hand
so it gets used the most.

 


 



 


What little crud in the valve is enough to make it leak.
Before this valve goes back together the valve  need to be cleaned polished with a new seal in the valve stem.

 

Crosman MK Safety Repair

Every MK comes to us with its own issues,

This is why at times things take so long. If its a simple rebuild or a complete restore, fixing pot metal or welding safety's they all take there own time, some are quick and easy to fix, others are more time consuming, either way they need to get done.

http://www.airgunsmith.com/Crosman_MK2/images/sa1.JPG http://www.airgunsmith.com/Crosman_MK2/images/sa1.JPG http://www.airgunsmith.com/Crosman_MK2/images/sa1.JPG

I almost welded this safety without pictures. the carbon pitting can be filled but
with such thin and brittle steel, get in get it done, make sure it will hold then call it good.
 


Valve stem check valve body



When performing a Crosman MK 1 or MK 2 Rebuild
This seal must be replaced or your work will be in vain.

 


 


Crosman Mark 1 Valve stem side by side with custom valve stem




This gun needs a new valve stem.
The one above still needs a bit of trimming
but the basic size it there.

 


The Crosman MK 1 and MK 2 Valve Stem Completed




Never use pliers or a vise
on the valve stem, it will snap.

Use heat and a  brass hammer.

This dried out old seal has done its job
for years, but now its time for a new one.



As you can see the seal is brittle and useless as a sealing surface. 


Now that everything is done, don't forget
The piercing cap pin seal



Without this O-ring you may as well vent your Co2 into the air.


Also if you don't have a tool to remove the piercing guide nut, GET ONE, its real easy to damage the nut and once its gone its gone!
 


 

Below is a damaged piercing pin nut we had to remove from the piercing body, the threads above the nut were damaged, luck was on our side the damage was high enough we could use a tap to get most of them straight.
 


Crosman MK 1 & 2 Cocking Knob Replacement


Sometimes the cocking knob gets lost.
Machining a new one is an option.

We have found using Brass black
is not as satisfactory as using an old
gunsmith process to patina the brass black 

Slim Knob



It holds up much better and has a very nice finish
 

Crosman Mark 1 & Mark 2
Valve Stem with new seal, there are
a few different materials that can be used.
two of the best are Polyurethane & Teflon.

After pressing the stem into the valve head
 this valve stem will be good for the next couple of generations.


Teflon Stem Seals
 


This is the
 O-ring were after


The real issue with the damaged nut

 is the threads in the piercing body, if you damage them it gets real hard to un-screw the guide nut over the damaged threads


Crosman MK 1 Piercing Body Threads
Cleaned up




 

Piercing cap pin seal Mid 1975



Not one of the best designs the slotted part on the right looks as though it would unscrew
but its just a plug. held in with the plug retainer. the retainer needs to be pulled out with care, it needs to be flexed not bent.
 


If and when we remove the damaged nut
replacing the nut is either having a spare in the cabinet
 or machining one from steel, we have used Navel Bronze
it seems to work fine with no issues. One would think the nut is made of hardened steel but its not, its soft as butter.
If you were to have only one tool for the MK, I would say this would be the tool to have, this is a very thin walled part, damage comes very easily
 


We were able the save the piercing pin nut & the
piercing pin body, sometimes things don't
work out so good, but this time everything fell in place.



You can see how short the nut is.


Now for the final touch,
snug down the barrel nut.



Another good thing to do is to use a good oil on the nut when you assemble the cap, I use nickel paste, this insures the next disassembly is a smooth one.
 

Crosman MK-1 & 2 Restoration

Re-building the Crosman MK-1 and MK-2 Piercing Pin Assembly
 
Lets face it, sometimes things get out of hand and right into the jaws of pliers.
 I can say with almost 100% certainty we have all used pliers and damaged whatever it was we were working on
and once we made a little damage care and concern for aesthetics gets thrown out the window.

Since these piercing assemblies are no longer made this is where restoration comes in.
First we disassemble clean all the sharp edges then we get to restoring the knurl.
After the knurl is complete we blue and reassemble with new seals. 
 

Before After Done
 

Crosman MK 1 and 2 Piercing Pin Custom Replacement 

I'm not sure why these break but when they do all is not lost.
The pin we machine is a bit longer to open the Co2 cartridge a little more
then the stock pin. I haven't done too much research, making the replacement
wasn't so much about performance increases as it was to just replace the broken part.
When I get the time I will show the entire piercing assembly we make to replace the lost set up.      

http://www.airgunsmith.com/Crosman_MK2/images/Perc_1.JPG http://www.airgunsmith.com/Crosman_MK2/images/Perc_1.JPG

 http://www.airgunsmith.com/Crosman_MK2/images/Perc_1.JPG http://www.airgunsmith.com/Crosman_MK2/images/Perc_1.JPG


 

 

Professional Quality Airgun tools by Airgunsmith
 

Piercing Pin Guide Nut Tool
 



 

 

 


Barrel Nut Tool


Valve Puller

 


 Valve Seat Stone

 


You will see some tools made of steel and some of brass still others of the harder bronze.
We do this by design to save the airgun from tool damage.

Wherever the tool is being used it is our intent
to use a tool of softer material if there is a potential of surface damage.

In other places we need a tool that will not only be of a proper fit
but be of sufficient hardness to cut into the part being turned or pulled
in this way when pressure is applied we make a very small indent insuring there will be no slippage. 

 

Crosman MK II Repair | Custom Crosman Airgun MK II Rebuild | Crosman MK II | Crosman MK II Maintenance | Crosman MK II Rebuild | Custom Made Crosman 2289 Airgun Parts

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