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Benjamin 137

Benjamin 137 Service, Rebuilding, Pump arm Repair, Dent Removal,


Benjamin 137 Pistol Rebuilding
Benjamin 137 Manual 
 


 


Benjamin 137 Rebuild Information    

Benjamin 137
Tool Set & Rebuild Kit

We manufacture Parts and Tools for the Benjamin 137
 


Pricing on Benjamin 137 parts are as follows.

Piston $25.00 each
Seal Kit $10.00 each
Piston Seal kit Combined $32.00

Rebuild service, $35.00 includes everything needed except the piston,
Piston with rebuild $25.00.
Total parts and service for Benjamin 137 Rebuild $55.00
 


Benjamin 137 Rebuild Service
with Piston $60.00
Priority Shipping $8.95

 Total $68.95
 


Benjamin 137 Pistol



On the left is the complete rebuild kit with optional seals
On the right is the seal kit and is most commonly used
with a new piston.

The Benjamin 130, 132 and 137 seal seat is rounded
in shape which makes hard seal material non functional.
The softer seal material allows the spring pressure to mold over
the seat making a good seal. It is possible to reshape the seat
giving the seal a sharper edge allowing the use of a harder/Teflon seal,
this is a one shot proposition and should only be used if the seat
in its original condition fails to seal.

This is the Rebuild Kit we offer for the Benjamin 137.
Everything is designed to have replaceable seals with the
hard parts being reusable, The Red Disk Is the Hardest,
The White is Teflon and the Orange is the softest.
also available is the thickness of the seal. Spring tension
is also changeable with the use of different springs.

This is the Rebuild Kit we offer for the Benjamin 137.
Everything is designed to have replaceable seals with the
hard parts being reusable, The Red Disk Is the Hardest,
The White is Teflon and the Orange is the softest.
also available is the thickness of the seal. Spring tension
is also changeable with the use of different springs.

 


Benjamin 137 Piston
Fits Benjamin 130, 132 & 137

$25.00 

Benjamin 137
Rebuild Kit  With Piston



$32.00
 

 


Benjamin 137 Rebuilding Kit Options

The kit above shows the options  available. Teflon in two thickness polyurethane is the material of choice in two thickness. Lead seals are also available, I use them both but O-rings are a lot easier to work with.

Consider this the most important screw on your Benjamin 137.


 

When removing this screw to periodically clean the Benjamin 137 piston for cleaning the pump  piston and tube, be sure to back this out 1/4 turn, no more, as you can see from the above picture someone has already tried that and all but destroyed it. I was able to grind a driver to fit the slot, but its not going to last for too many more cleanings.

 

 

 

For the Benjamin 137 Rebuild
see below



 


 

 


(This looks to be the Benjamin 137 original finish)
 
We do have limited parts for  this pistol, We manufacture Benjamin 137 seals in Lead, Teflon and Polyurethane.

If you need parts shoot us an email

 


 


This is where is all starts, when using a slotted head set screw, everything works fine at first then someone goes and tightens it too much, that pushes the setscrew slot edge over into the brass threads



Then they unscrew it taking a little brass with it   every time its turned until it jams

 

Yes the slot edges did twist off as I was
trying to remove the set screw




This is not an easy fix, 
Today was the day I started the not easy fix
of  drilling the set screw out of the Benjamin 137



This is not always the best way to start stud removal but if everything is lined I'll get a straight hole

 


Drilling small screws for stud removal drills bits seem to wander, I like to use a center cut end mill and slowly cut the screw out, if by chance I had a left hand and I was lucky, it would unscrew half way down.

 


Today I don't have a left hand in this size
so it looks like I'm in for the full ride.
 


Having got that done, its on to threading
before anything is moved, using the drill press to start the tap gives a clean square start.


With the tap started by machine and since there is a bottom to the hole Ill complete the thread by hand
 

 


Its always a good feeling to get the job done.
when working on what seems like a one of a kind, its not, but trying to find a replacement is near impossible


Now for the proper set screw


At a later date I will clean up the edge of the hole so it looks good under a magnifying glass




 


Done and back together



 


Benjamin 137 Pump Arm Repair

 

On the left is the pump arm in need of repair. Note the spring under the pump arm.
that is what holds the pump arm in the up position, unlike the crosman the Benjamin
needs a bit of clearance between the piston and the valve. This is a good time to say, Keep
it oiled, if the spring breaks the only option is to disassemble the pump arm make a new
spring. On the Right is the Pump Arm complete,   

  

Bottom left is the Benjamin 137 re-assembled the right full Benjamin 137 complete

The Benjamin 130, 132 and 137 are very nice old guns and like anything else
suffer from lack of maintenance, Keeping them lightly oiled on all moving parts
with quality airgun oil is a move in the right directions for another 50 years of service. 

 


Benjamin 137 Breech Separation Repair

 


Benjamin 137 Breech Separation
Repair Start


 


To re-solder the breech on the Benjamin 137
$20 to $30 depending on the amount of
work to remove the old solder.

 


 


Benjamin 137 Breech/Receiver Separation
Repair Completed

http://www.airgunsmith.com/Benjamin_137/Images/Benjamin_137_Breech_Soldered.JPG
 
For a larger Image click here


Brass needs a bit more heat then other metals in order to work properly
This image we can see a small amount of discoloration from the heat


With this Breech we went ahead and removed the breach, barrel and sight from the tube, what I found was the front sight sleeve had no solder under the sleeve, all the solder was on the out side along the edge. This condition most likely contributed to the breech separation.

 This is a rebuild with a new AGS Benjamin 137 Piston

After reassembly the chronograph test results are
pretty good, All with 10 pumps.
472.3 - 540.0 -  539.9 - 532.2 - 517.0
 


     As the Benjamin 137 Pistol ages breech separation is a common occurrence and is somewhat of a simple repair, the most difficult
part is removing the old solder. It is not necessary to completely remove the barrel and breech unless the front sight shows signs of
corrosion, Also if the front sight comes loose total removal of the barrel and breech is not needed. If I was to say the most (important) part about soldering, it would be to get both parts at the same temperature, if not the end result will be a cold solder joint/connection.  Not much solder is needed to join the two parts together, the process is simple, remove the old solder clean it good, apply a good flux use a good lead alloy mix, heat the parts the same temperature needed to melt the solder being used and the solder will flow
right where it belongs, Everywhere the flux was applied.

 

 


Repairing the Benjamin 137 Dented Pump Tube

Repairing the dent in the brass tube is not that difficult of a task, what we need to take into account
is the brass hardness, lack of understanding here will lead to cracks in the tube.
On this sample never mind the self repair linkage pin by cutting out the tube so a cotter pin
could be used, it may not look that great but the function is perfect.
 

http://www.airgunsmith.com/Benjamin_137/Images/137_Dent_1.JPG

  For a larger Image click here
http://www.airgunsmith.com/Benjamin_137/Images/137_Dent_3.JPG

  For a larger Image click here
 


Here we can see the dent is completely gone
 

http://www.airgunsmith.com/Benjamin_137/Images/137_Last_c.JPG

For a larger Image click here


It takes time but dented pump tubes are not the end
of a guns life into the parts bin.

http://www.airgunsmith.com/Benjamin_137/Images/137_Dent_last_A.JPG

For a larger Image click here

This little 137 will have many years of shooting

 

 

http://www.airgunsmith.com/Benjamin_137/Images/137_Dent_q.JPG

For a larger Image click here

 

 

http://www.airgunsmith.com/Benjamin_137/Images/137_Dent_R.JPG

For a larger Image click here

 


If you do get a dent in your pump tube the gun is not trash, it can be fixed to a point
you would never know it was there.

Here we go with the Benjamin 137 Pistol for the full rebuild

The biggest pain is getting the valve seat nice and clean for the new seal, unless.



You have a tool 



Ok not a very good picture but its easy
to see its nice and clean.


 Here are the numbers


 

These are some nice numbers for the little Benjamin 137.

 



Benjamin 137 AGS
Piston
Fits Benjamin 130, 132 & 137

$25.00 

Benjamin 137 Rebuild Kit
 With Piston



$30.00
 

 


The Benjamin 137 piston works by oversized rubber
getting forced down its little 137 throat. 


We will be changing this to a modern light weight piston
sure to give the Benjamin 137 a boost in power.

 


We just finished a 137 with new made parts
and modified valve.,
this is all with 10 pumps and the
last shot with no pumps just shooting with what is left
in the valve.



I don't recommend pumping the Benjamin 137 10 times for every shot
but if you need a little more FPE for a shot or two out of this 40 year old Gem,
you can sure get it.


I think we have covered most of the common issues with the Benjamin 137 except modifications.
I have a Benjamin 137 that needs some work, as soon as I get some time I will
post the modifications here.

The modifications on the Benjamin 137 are no cake walk, there is a lot of work just getting
to some of the parts let alone modifying them for improvements.
 

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