Air Rifle Repair Manual
Copyright 2014, UJ Backus
This Manual is intended to be a guide for those seeking information on the repair of Sheridan air rifles.
It is not instructional material and only those who have proper skills should attempt repairs.
The Author therefore assumes no responsibility.
ALL RIGHTS RESERVED
Index
Preface.............................................................................................................................................2
Model A and B parts diagram (Super-Grade and Sporter).............................................................2
Model A and B information............................................................................................................3
Model C and C-SERIES parts diagram (Silver Streak and Blue Streak).......................................5
Pneumatic rifle pump cup replacement..........................................................................................6
Pneumatic rifle valve seals replacement.......................................................................................10
Model F and F-SERIES parts diagram (CO2 Silver Streak and CO2 Blue Streak)....................16
CO2 rifle valve seals replacement................................................................................................16
Model C9-SERIES and F9-SERIES.............................................................................................18
Model F9A-SERIES parts diagram..............................................................................................19
Cartridge valve seals replacement................................................................................................21
Part numbers.................................................................................................................................22
A note on barrel separation...........................................................................................................23
Tranquilizer guns and paintball markers......................................................................................23
1
Preface
An understanding of the mechanics of air guns is necessary in order to perform repairs properly and safely.
Sheridan air guns are of the pneumatic type and the CO2 gas type. Care must be taken during disassembly and
all parts cleaned with a proper solvent. Alcohol is adequate for most parts. Lacquer thinner and #0000 steel
wool can be used to remove heavier grunge and stains. For re-assembly, light grease and non-detergent oil
should be used sparingly in the proper places. Keep in mind that the barrel and air tube are made of brass
compounds that have self-lubricating properties. The bore need only be cleaned with alcohol and a soft cloth
patch. Wood should be carefully cleaned and preserved with light oil. Several products are available that can
restore the wood to a presentable condition without destroying its originality. Formby’s Lemon Oil Treatment
and Birchwood Casey Tru-Oil give good results. To preserve collector value, re-finishing should be avoided
unless it is deemed necessary due to excessive wear and/or damage.
The text and photos in this manual will guide the individual in the repair of Sheridan air rifles. Replacement
parts, as well as the special tools needed, are available through several sources which can be searched out on the
Internet. The exception is the Super-Grade and Sporter. Although replacing the pump cup is fairly easy and
requires no special tools, replacement pump cups are not readily available. Repair of the valve is difficult, parts
are scarce, and special tools are required. Therefore, it is best to send these models to a qualified airgunsmith.
Super-Grade and Sporter
Model A pneumatic rifle / Model B is basically the same
2
Model A and B information taken from the owner’s Hand Book
Operation
Open bolt and draw back slightly until it stops against the main spring. Pull bolt back hard against spring
until sear engages with a “click”. Bolt is now free and should be closed again so that safety lever can be
operated. Do not jamb bolt handle down hard when closing. The front of the bolt provides a tight seal in the
barrel when it is closed with very little pressure.
Move safety lever to rear to put on “Safe” and forward again for “Fire”. The safety can only be operated
when the rifle is cocked as described above.
Charge the rifle with the desired number of pumps. As with the operation of the safety, the rifle can only be
charged when cocked.
Open bolt and insert bullet (pellet) into chamber at rear of barrel. Push bolt forward forcing bullet (pellet)
into rifling and close bolt. Again, as described above, do not jamb bolt handle down too hard. This saves the
camming surface on the receiver from unnecessary excess wear.
Shoulder rifle, take aim at target, move safety to “Fire” and squeeze trigger. FOLLOW ALL SAFETY RULES.
Valves
In a pneumatic rifle dirt on the valves or valve seats will naturally cause air leakage. The Sheridan is
constructed so that it can be “blown out”. That failing to remove the dirt (in case of a gummy sludge) it can
even be washed out without taking the mechanism apart.
1. To blow out the valves, merely pump rifle two or three strokes without cocking the action. Make sure
before doing this however that there is no bullet in the chamber.
2. To wash out the valves, raise pump lever to top of stroke and squirt a drop or two of light oil in the small
air intake hole in the pump tube and (also with action not cocked and rifle unloaded) work the piston to
blow oil and dirt on through. This will also lubricate and prevent rust on such internal action parts as
valves, firing pin, striker, etc. After doing so, shoot rifle a few times unloaded and against something the
oily blast of air cannot spoil. The oil fouling in the barrel should also be cleaned out to retain top velocity
and accuracy.
Model A and B valve unit components
3
Do not think valves are dirty or leaking if the pressure developed by one or two pumps is not retained in the
air chamber over a lengthy period. To withstand pressures up to half a ton, which may be built up in a Sheridan,
it is advisable pneumatic engineering not to use a soft valve-seat that would readily seal a few pounds of air, but
not hold the higher pressures.........No practical shooting is attempted with only one pump, and two or more will
provide sufficient air pressure against the hard and sturdy valves to seal the chamber.
When your Sheridan is not used regularly.......you may encounter normal slight seepage. It will disappear
with use – or if the rifle has become extremely dry – with a drop or two of light oil in the air intake hole under
the pump lever forced through the valves, by pumping with the action not cocked, in the same manner dirt is
washed out.................If slightly dry and seeping, a heavy charge of half a dozen strokes left in overnight will
usually completely seal up the chamber.
Dismantling
1. To adjust trigger pull: Remove stock by pushing out safety lever pin and taking out safety lever (Model A
only). Then remove forward and rear receiver screws (the two large screws on the underside of the stock).
Open pumping arm slightly, and carefully remove action from stock. Pull can be adjusted by changing the
position of the sear spring on the notched tang. Move backward to lighten and forward to increase weight.
2. To adjust bolt handle: The locking taper between bolt and handle allows one to set the later were
preferred. Keep in mind however that the front end of the bolt body is also a needle valve to eliminate
leakage behind the bullet. If bolt handle is adjusted so low that it can strike the wood before needle valve
is in position, it will not form a proper seal. To change position of handle, loosen screw (on end of bolt)
with large screwdriver. Tap (bolt handle) loose and turn to desired position. Retighten (screw) very firmly
to avoid slippage.
3. To clean pump tube: Remove piston assembly by starting with screw on nose of muzzle cap. When this is
out, raise pump lever slightly and tap out pivot pin. Remove the two muzzle cap screws, and using a piece
of wood tap off the muzzle cap. This allows whole assembly to be withdrawn. A cleaning rod with a good
sized cloth over the end works well to clean out the tube. Wipe off and lubricate piston and cross head.
Also put a drop of oil in all working points (pivots), and one in the long slot of the pump lever for the leaf
spring.
Tips on Re-Assembly
When replacing stock on action raise pumping arm slightly and action will slip into place readily. The longer
of the two stock screws goes in the back of the trigger guard. Do not reverse them.
(Model A only) The safety lever is put in from the small slot in the safety lever plate so that the ball on the
bottom of the lever is in the hole in the safety slide. When this is in place, move lever back or forward until
cross holes line up, and push in pin. If lever slips in handling twist a narrow strip of tape around the very top (of
lever) to hold onto.
4
Controlled Power
Controlled power makes a really fine pneumatic a very practical rifle to own. For target practice in the
average length basement, three strokes of the piston are sufficient for accuracy. Outdoors at around twenty five
yards, five or six strokes should be ample for general use. Velocity and point of impact can be regulated for
target work, hunting, plinking, etc., by the number of pumps and how they are handled, fast or slowly. It is
always sensible to use no more power than is needed for the job.
Important
Do not put in over eight pumps because the rifle is designed to operate most efficiently with moderate
charges. Do not over-charge and possibly cause an over-heated piston head, scorched valves, or air lock. The
muzzle velocity with eight pumps of the efficient piston is more than necessary or practical for the use to which
a pneumatic rifle is adapted (note: muzzle velocity with eight pumps averages 650-700 fps).
Consult a qualified airgunsmith for repairs
Silver Streak and Blue Streak
Model C and C-SERIES pneumatic rifle
5
Pneumatic rifle pump cup replacement (except Model A and B)
drive out the two roll pins from front of air tube and remove muzzle cap
cross head pin pushes out through roll pin hole
this pin secures the pump arm linkage to the pump rod cross head
6
withdraw pump rod from air tube
clean all parts including inside of air tube
7
there are three styles of pump rods
top is adjustable with pump cup molded into piston head used to about 1961
middle is adjustable with pump cup press fitted in piston head used to 1964
bottom is non-adjustable with press fitted pump cup used to end of production
remove old pump cup
molded in style unscrews and is replaced with custom piston head
press fitted type often needs to be chipped or burned out when brittle
8
new pump cups are of the press fitted type
top shows pre 1962 original piston head with molded in pump cup
bottom is custom piston head for pre 1962 which accepts press fitted pump cup
oil perimeter of new pump cup to aid in pressing it into the piston head recess
with new pump cup installed and lightly oiled, insert pump rod into air tube
adjustable rods should be set to length for maximum travel, which requires trial and error fitting
this reduces space between pump cup and inlet valve which will result in maximum power
re-install pump arm linkage and cross head pin
re-install muzzle cap and press the roll pins in with a vise
apply light oil at cross head, pump lever pivot, and pump lever arm at muzzle cap
9
Pneumatic rifle valve seals replacement (except Model A and B)
remove trigger/sear by driving out retention pin
drive out end cap retention pin / CAUTION: end cap is under pressure from striker spring
10
some persuasion may be necessary to remove end cap
CAUTION: end cap is under pressure from striker spring
earlier models use three screws to retain end cap
11
remove striker, spring, and guide / earliest style striker is shown on left
note ring on center striker; many have just half a ring which faces down when installed
tools needed to remove valve components
12
remove valve retainer nut and then valve body / the remainder of the valve parts should fall out
sometimes it is necessary to push the parts out with a stiff wire inserted from the inlet side
be sure to remove valve body seal which is usually stuck inside the chamber
surface in chamber where seal seats should be carefully scraped clean
new inlet valve, exhaust valve, and valve body seal shown at top
early valve components with original valves and seals shown at bottom
some rifles use two washers / valve body seal can be either lead or rubber
clean and inspect all parts
13
clean inside of tube, air chamber, and chamber threads
make sure retainer nut screws easily into chamber
if necessary, tap for chamber threads can be made by cutting slots in a spare steel retainer nut as shown
apply a light application of oil to surface of seals
drop inlet valve, inlet valve spring, washer(s), and exhaust valve spring into chamber
small end of exhaust valve spring faces base of exhaust valve / refer to photo on previous page
install valve body with seal and exhaust valve as shown / take care to not cross-thread retainer nut
early valve bodies have a single exhaust port; later valve bodies have two or four exhaust ports
be sure to properly align the early single port valve bodies / they have a tab that fits a slot in the chamber
Note: Retainer nut lead seal is omitted in photo. If blow back is evident when firing rifle and bolt-to-breech seal
is properly adjusted (see bottom of next page), then retainer nut lead seal should be installed.
14
apply light coat of grease on surface of striker and on trigger/sear attachment point
install striker (half ring down if applicable), striker spring, spring guide, end cap and trigger/sear
tools needed to remove bolt if required / take care to not loose bolt tension spring
1951 to 1955 bolts also have a small pin that must be driven out before removing cocking lug
the receiver on these rifles will have a small hole on right side that aligns with pin
drive pin out from left side of receiver after removing locking cam and cover
Note: Bolt should seal breech when closed. Adjustment is made by moving locking cam forward or to the rear
as necessary. Bolt handle should not contact stock in closed position when properly adjusted. If applicable,
replace damaged or worn o-ring on bolt loading pin with size AS568-004.
15
CO2 Silver Streak and CO2 Blue Streak
Model F and F-SERIES CO2 rifle
CO2 rifle valve seals replacement
remove trigger/sear, end cap, striker and spring, retainer nut and valve body as outlined for pneumatic rifles
valve components
chamber plug has a slotted sleeve attached / larger chamber sleeve is made of brass
valve body seal is rubber / retainer nut seal is lead and can be omitted as with pneumatic rifles
16
insert spent CO2 cartridge and tap with wooden dowel to work chamber plug loose from tube
use a ¼” rod to drive chamber plug and sleeve out rear of tube
clean all parts, inside of tube, and chamber threads as outlined for pneumatic rifles
17
this shows the old seals, and the chamber plug and valve body with new seals installed
re-install valve components in tube
complete re-assembly with installation of striker, striker spring and guide, end cap, and trigger/sear
C9-SERIES and F9-SERIES
Pump cup replacement for the C9-SERIES is the same as described previously. Valve seals replacement for
the C9-SERIES and F9-SERIES rifles made before 1995 is also the same as described previously, except for the
trigger/safety assembly which is shown in the following F9A procedures.
The following procedures also show the removable cartridge valve found in 1995 and newer models.
18
Model F9A-SERIES CO2 rifle
remove trigger spring components
19
drive out trigger/sear retention pin and remove safety components
Note: retention pin has knurled end and must be driven out from proper direction
take care to not loose safety detent ball and safety spring located in end cap
remove three screws securing end cap and withdraw cap, striker and spring from tube
Note: use a 7/64” allen wrench to remove bolt cocking lug if bolt is to be removed from receiver
20
Cartridge valve seals replacement
remove stock lug, which also serves to secure cartridge valve in tube
drive out cartridge valve assembly with wooden dowel
Note: in pneumatic rifles the cartridge can sometimes be blown out by activating the pump
CO2 cartridge valve components shown at top
pneumatic cartridge valve components with o-rings installed shown at bottom
unscrew valve body and clean parts; re-assemble cartridge with new seals and o-rings
install cartridge in air tube and re-assemble rifle in reverse order
21
pre 1995 pneumatic rifle part numbers:
pump cup
inlet valve
exhaust valve
valve retainer nut
397-025
10010
397-038
68AT-034
pre 1995 CO2 rifle part numbers:
chamber plug
chamber plug o-ring
chamber plug sleeve
chamber sleeve
face seal
valve spring
exhaust valve
valve body seal
valve body
lead seal
valve retainer nut
F500
F500-0
F500-1
F500-2
G397-012
G397-011
FX505-3
68AT-035
68AT-033
68AT-032
68AT-034
pneumatic cartridge valve part numbers:
complete valve assy
exhaust valve body
exhaust valve body o-ring
exhaust valve
valve spring
inlet valve body
inlet valve body inner o-ring
inlet valve body outer o-ring
check valve
397-032
397-033
397-036
397-038
397-035
397-034
397-037
JTX-080
1322-056
CO2 cartridge valve part numbers:
complete valve assy
exhaust valve body
exhaust valve body o-ring
exhaust valve
valve spring
inlet valve body
inlet valve body inner o-ring
inlet valve body outer o-ring
face seal
piercing stem guide
G397-008
397-033
397-036
2250-016
788-061
G397-009
397-037
397-040
G397-012
G397-010
22
A common issue with Sheridan pellet rifles, other than the Model A Super-Grade, is barrel separation. The
solder joint along the barrel and air tube can break due to stress or age. It is well known that the clip-on rear
sight used on 1971 and later pellet rifles can cause stress on the solder joint. An improperly attached scope
mount can also cause stress on the joint.
To check for barrel separation shine a bright light along the barrel/air tube seam and note if any light passes
through the solder joint. Also, pinch between the muzzle and air tube to check for separation at the front sight.
In some cases the receiver can become separated so check that it cannot be lifted from the air tube.
Barrel separation can be repaired by anyone who has good soldering skills. In most cases the heat applied
will not damage the nickel finish on a Silver Streak. However, the repair area on a Blue Streak may need to be
re-finished.
In the case of minor separation caused by the clip-on rear sight, it is advised to remove the sight to prevent
the separation from worsening. There are different methods to remove the sight. One way is to tap it from front
to rear while holding the wedges stationary so that the sight can slide off of them. If it is desired to retain the
open rear sight, the solder joint will need to be repaired. A pair of wedges can be fabricated from plastic and the
clip-on sight re-installed using these plastic wedges. A better option is to install a Williams receiver sight.
Tranquilizer guns and paintball markers
Except for removal of the bolt, repairs for the Model G and later tranquilizer guns and the K-SERIES
paintball markers are basically the same as pellet rifles from the same era.
On tranquilizer guns the cocking handle is screwed directly into the striker. The handle must be removed to
withdraw the striker from the tube when servicing the valve. The swing-open loading bolt on later style guns
does not normally need to be removed for cleaning or o-ring replacement.
Model 176B shown with loading bolt in open position
23
On K2 with the bolt closed remove the cocking lug from left side. Bolt can now be withdrawn from rear.
On KP2 remove stock to clear pump handle. Push pump rod up to rotate bolt clockwise so cocking lug is
accessible for removal.
Withdraw bolt taking care to not loose spring loaded detent ball(s). Bolt unscrews from pump rod.
Note: some bolts are secured to pump rod with set screw and can be withdrawn with stock in place.
24
On KP3 and KP2-DF with quick change bolt; pull knurled knob on rear of bolt and withdraw pump rod from
bolt. Turn bolt clockwise so cocking lug protrudes through slot on left of tube. Depress spring loaded lug into
bolt and slide bolt out to the rear.
Note: detent balls remain secure in bolt assembly.
Run cleaning patch through tube when bolt is removed.
Lightly oil bolt o-rings to aid in re-installing bolt into tube.
To learn more about Sheridan air guns refer to my book, “SHERIDAN / Classic American Air
Rifles”. It has information on Company history and details about the various models produced.
Also included is information on pellets, shipping boxes, literature, and other items of interest.
Every serious collector should have a copy in his/her library.
25