Keiser Keiser 300 User manual

Keiser 300 / Air 300
Parts and
Maintenance
Manual

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Table of Contents
Introduction – How it Works 4
Preventive Maintenance 5
Troubleshooting 6
Air Hoses and Fittings 7
Filter 9
Valves 10
Cylinders 14
Mufflers 17
Fasteners 18
Arm Locks 19
Bearings 21
Hand Grips 23
Upholstery – Decals 25
Parts Identification 26
SAFETY CAUTIONS:
We’ve put a number of safety cautions in this book. We use the word CAUTION to tell
you about things that could cause bodily injury to persons on or around the equipment if
you were to ignore the warning.
MACHINE DAMAGE NOTICE:
Also, in this book you will find the word NOTICE. This tells you about things that
could hurt the machine if you were to ignore these warnings.

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K300 – HOW IT WORKS
Two basic systems are used to operate the KEISER 300 series exercise machines.
On machines that exercise the muscle groups of the upper body, the resistance is
controlled by means of foot pedals mounted on the base of the machine. Thumb buttons
in the handles operates machines for lower body muscle groups.
When the quick-disconnect is plugged into the air system, compressed air flows
into the machine. In all but the Seated Chest Press, Lateral Shoulder Raise, Military
Press, Tricep, and Seated Butterfly, the air flows through the filter to the increase valve
(in the machine above, the filter is in a different location, but its function is identical).
The filter removes moisture and particles, which may be harmful to the cylinders.
When the increase valve is depressed, the air flows into the cylinders, tanks, and
gauge through one or more manifolds. Moving the exercise arm through its range drives
the piston in the cylinder against the air pressure. The air, in effect, pushes back against
the piston, creating mechanical resistance. When the increase valve is held down, the
resistance becomes greater until the maximum cylinder pressure is reached.
Depressing the decrease valve opens the system to the atmosphere, allowing the
cylinder air to escape. The resistance decreases as the pressure is reduced.
The gauge is calibrated to show the maximum amount of resistance developed by
the machine. The gauge reading is correct when the exercise arms are against their stops.
The gauge needle will move during the exercise motion. This is characteristic of the
system and does not indicate a malfunction.

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PROBLEM: Pressure changes without valves being actuated.
Service the Valves (see pg. 9)
AIR HOSES AND FITTINGS
All K300 machines use polyethylene tubing and “Compress-align” fittings to connect the
various pneumatic components within the machine.
If an air leak is suspected, first listen closely to the air hose connections. Leaks will
make a hissing noise. Very slight leaks may not be loud enough to hear. These may be
detected by dabbing soapy water on the suspected leak. Escaping air will make bubbles.
If the leak is at a fitting, first tighten the nut about one-quarter (1/4) of a turn. Test the
connection again. If the fitting still leaks, the nut must be replaced. In most cases the air
hose should be long enough to allow this; if not, order a new air hose from KEISER.
To install a new nut:
TOOLS REQUIRED: adjustable wrench and a sharp knife
1. Cut the tubing as close as possible to the nut. The cut must be clean and square.
2. Slip a new nut over the tubing.
3. Insert the tubing into the fitting all the way to the shoulder inside the fitting (see the
cutaway illustration).
4. Hold the tubing in the fitting and slide the nut down onto the fitting. Tighten the nut
as tight as possible with the fingers, then another one full turn with a wrench.
If reinstalling an air hose, tighten the nut finger-tight, plus one-quarter (1/4) turn. This
will allow the nut to be used three more times before it must be replaced.

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QUICK – DISCONNECT
The feed hose is connected to the quick-disconnect and the machine with compress-align
fittings. If the feed hose must be repaired or replaced, follow this procedure:
1. To replace hose, unscrew the compress-align nuts on both ends and remove the hose
(new hoses and compress-align nuts are available from KEISER).
2. To shorten the hose, unscrew chrome compress-align nut from the quick-disconnect
and cut the hose to the desired length. Slide a new chrome nut (an extra one is
supplied with each machine) onto hose.
3. To tighten the compress-align nuts, slide the hose all the way into the fitting and
thread the nut on hand-tight. Tighten the brass nut one full turn more with a ½ in.
open-end wrench. The chrome nut may require more turns, due to the chrome on the
threads. Make sure the hose is held securely in place at both fittings.

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FILTER
The air filter keeps moisture and dirt out of the cylinders and other components. The
filter bowl must be kept free of moisture. Filter bowls that fill quickly with water
indicate a problem with the air dryer. If your air system does not include a dryer, the
filters on all machines must be checked and/or drained daily.
This is best done by pressing on the drain valve until all moisture blows free. The
moisture can be caught in a towel. CAUTION: IF THE FILTER BOWL IS CRACKED,
IT MUST BE REPLACED IMMEDIATELY. NOTICE: IF FILTER BOWL IS
CRACKED, AN AIR LEAK COULD RUN THE COMPRESSOR CONTINUOUSLY,
PUTTING EXCESSIVE WEAR ON THE COMPRESSOR.
The internal parts of the filter and the bowl can be cleaned. Always decrease resistance
to zero before starting service or repair on any K300 machine.
To service:
Unplug the quick-disconnect and unscrew the bowl and element holder from the housing.
Clean all parts with dish soap and water. Do not use solvent or other strong chemicals on
any part of the filter. Allow the element to dry thoroughly. Lightly coat the bowl seal
with SAE 30 wt. Oil and reassemble. Leaky drain valves can be replaced with a bicycle
tire tube valve available at most hardware stores.

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VALVES
The valves in the pedals or handles can be removed for service or repair. Always unplug
the quick-disconnect from the air system and decrease the resistance to zero before
working on the valves. The following groups of machines state the type of valve and its
maintenance procedures.
LEG EXTENSION, LEG CURL, SQUAT, HIP ABDUCTOR, LEG PRESS,
STANDING HIP, ABDOMINAL, LOWER BACK, AND SEATED CALF
1. Trace the hoses on the valves to their connections on the filter or manifold. An
increase valve is connected to two hoses, one from the filter and one to the manifold.
Decrease valves are connected to one hose from the manifold and one from the
exhaust muffler. Mark the hoses with tape so they can be reassembled properly, then
disconnect.
2. Decrease the resistance to zero. Remove the grip end cap from the handle and pull
the valve out to a point where the hose can be cut about ½ inch from the bottom of the
valve housing. Cut the hoses clean and square, and cut the small remaining piece off
the barbed fittings. NOTICE: DO NOT DAMAGE BARBS. DAMAGED BARBS
ARE AREAS FOR POSSIBLE LEAKS.

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3. Rest the valve housing on the open jaws of a vise and drive out the spring pin with a
hammer and 3/16-drift punch (see illustration below). When the punch is removed,
the spool can be removed as shown.
4. Remove the O-rings off the spool. CAUTION: DO NOT CUT SPOOL! CUTS IN A
SPOOL ARE AREAS FOR POSSIBLE AIR LEAKS. Wipe the spool completely
dry with a clean dry cloth and inspect it carefully for signs of wear or deterioration.
Lightly coat the narrow part of the spool with silicon lubricant and slip on three new
O-rings.
5. Clean the inside passages of the valve housing with solvent and compressed air. Do
not use any kind of tool inside the housing. Inspect the bore for scratches or wear of
any kind. The housing should be replaced if there are any imperfections in the bore.
6. Assembly is the opposite of disassembly. Tap the spring pin into the spool until it is
just flush with the outside of the housing.
7. For increase valves, push the air hose from the filter over the barb on the high-
pressure side of the valve (see illustration), and the air hose to the manifold on the
low-pressure side. Push the hose all the way up to the flange. For decrease valves,
the air hose from the manifold is connected to the high pressure side, and the air hose
from the muffler is connected to the low pressure side.

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8. Replace the valve in the machine and remount the end cap on the end of the handle (if
you have any questions on the preceding steps, please contact our service
department).
SEATED CHEST PRESS, LATERAL SHOULDER RAISE, MILITARY PRESS,
TRICEP, AND SEATED BUTTERFLY
NOTE: Machines shipped before October, 1985 have nuts and bolts holding the valves in
place. Later machines use only flat head screws for easier access to the valves. The
procedure described here applies specifically to the older machines but the same general
procedure also applies to the new machines.
TOOLS REQUIRED: 5/16, 3/8, 7/16 open-end wrenches, screwdriver
1. Tilt the machine back and lay it down so that the pedal assembly is easily accessible.
NOTICE: REST THE MACHINE ON FRAME MEMBERS ONLY. TO PROTECT
AIR HOSES AND FITTINGS.

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2. Loosen the adjusting screw behind the pedal. Hold the nuts on top of the valve with a
3/8 open-end wrench and remove the screw with a 5/16 wrench or socket. The valve
can now be lifted off the link, and the valve cartridge removed for service or
replacement. On machines shipped after October, 1985, a standard screwdriver is
used to remove the valve mounting screws.
3. Assembly is the opposite of removal. Use the adjusting screw to make the pedal even
and parallel to the ground. Lock the adjusting screw in place with “Loctite 292”.
VALVE SERVICING
TOOLS REQUIRED:1/2 inch wrench or socket, rag, DOW CORNING 111.
1. Remove the brass valve cartridge from the aluminum housing. Make sure that the O-
ring indicated does not remain in the housing. If it does, use the spring to remove it.
2. Push the spool out of the lining. Wipe all parts clean with a soft dry, lint-free cloth.
Do not use alcohol or petroleum-based cleaning solution. Check all parts for cracks
or excessive wear. Replace entire unit if worn or damaged.
3. Wipe a thin film of DOW CORNING 111 compound on the valve and bore.
Reassemble the valve cartridge.
4. Reinstall the valve cartridge. NOTICE: DO NOT OVER TIGHTEN.

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CYLINDERS
Three types of cylinders are used on K300 series machines:
2 ½ “ x 7” = Part #:11-5317
2 ½ “ x 12”= Part #:13-5316
4” x 12”= Part #:15-5314
Maintenance procedures are the same for all three types of cylinders.
TOOLS REQUIRED: adjustable wrench, 5/16 or ¼ inch allen wrench and an oil can.
REMOVAL:
1. Unplug the quick-disconnect from the air system and reduce the resistance to zero.
2. Remove the air hose from the cylinder. It is best to remove one cylinder at a time. If
both cylinders must be removed, mark the cylinders and air lines to avoid mistakes in
re-assembly.
3. Remove the nuts and bolts holding the cylinder and clevis. Check the bearings in the
tang end of the cylinder and the lever arm. If they are loose or worn, they must be
replaced.

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TO REPLACE THE CYLINDER:
1. Put a drop of oil on the bearings and remount the cylinder. Tighten all nuts securely.
2. Reattach the air hose. Tighten the nut finger-tight, plus ¼ turn. Plug in the quick-
disconnect and check for air leaks. If the fitting leaks, tighten the nut another ¼ turn.
If the leak persists, replace the nut.
CYLINDER SERVICING
NOTICE: IT IS VERY IMPORTANT THAT THE CYLINDER ROD AND BORE
ARE NOT SCRATCHED OR DAMAGED IN ANY WAY. DAMAGED CYLINDER
RODS AND BORES ARE AREAS FOR POSSIBLE AIR LEAKS.
TOOLS REQUIRED: 11/16 wrench or socket, internal snap ring pliers, rag and Mt-55
light grease
1. Using the 11/16 wrench, carefully remove the muffler from the end housing of the
cylinder.
2. Clamp the tang of the cylinder in a vise or have someone hold the cylinder. If the
ends of the snap ring are not visible, the end housing must be rotated until both ends
are visible through the cut-out.

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3. Pull the rod out 2/3 to ¾ of the way. Squeeze the snap ring with snap ring pliers and
pull on the rod to “tap” the end housing out of the cylinder (see illustration).
4. Wipe out the bore of the cylinder with a lint-free rag and inspect for scratches or
uneven wear. If found, contact KEISER for a replacement.
5. Clean the piston and inspect for wear or damage. If any metal particles are found on
the piston or inside the cylinder contact KEISER for a replacement.
6. Clean wear the strip grooves and apply a moderate coat of “Hydrotex MT-55” light
grease (available from KEISER) to hold wear strips in place during assembly.
Lightly coat the bore, cup seal, piston and wear strips with MT-55 light grease.
NOTICE: OPEN END OF CUP SEAL MUST FACE AWAY FROM THE
CYLINDER ROD. Carefully re-assemble the cylinder.
7. Apply a very light coat of lube to the muffler threads and reinstall snug, but not tight.
8. Operate piston by hand through its stroke. There should be no stickiness or metal-to-
metal contact.
9. Wipe the cylinder rods clean and coat them lightly with clean, SAE 30 wt. Motor oil.
ADJUSTMENT
Cylinders are factory adjusted and need not be readjusted unless the cylinder or clevis
becomes loose or is replaced. While each machine is checked differently, cylinder
adjustments are basically the same. TOOLS REQUIRED: 2 large adjustable wrenches

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1. Hold the clevis in position with a wrench as shown (1) and loosen the lock nut.
NOTICE: LOOSENING THE LOCK NUT WITHOUT HOLDING THE CLEVIS CAN
DAMGE THE BUSHINGS, CLEVIS AND THE CYLINDER ROD.
2. Adjust the rod length (2) as required.
3. Hold the clevis and tighten the lock nut. Watch the rod to make sure it does not turn
while tightening the nut.
MUFFLERS
The mufflers on the rod ends of the cylinders should be replaced at any time cylinder
problems are suspected. Removing the muffler and moving the exercise arm through its
range will determine if the muffler is clogged. A clogged muffler will make the motion
spongy or rough. When replacing a muffler, coat the threads with oil, silicon lubricant,
or “WD-40”, and reinstall snug but not tight. Mufflers on decrease pedal valves should
be checked or replaced if the resistance decreases slowly or incompletely.

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FASTENERS
NUTS AND BOLTS
Tightness of nuts and bolts should be checked monthly. Main frame bolts are generally
held in place through an internal mounting tube (see illustration). These bolts should be
tight (35-40 ft.-lbs.). Other bolts should not be tightened any more than necessary to
keep them from turning freely. NOTICE: OVER TIGHTENING BOLTS, WHICH GO
THROUGH THE MIDDLE OF TUBES, WILL CRUSH THE TUBE AND DESTROY
THE CHROME FINISH.
TOOLS REQUIRED: drift punch and a hammer
Spring pins are used to hold a shaft in place or to fasten a collar to a shaft. With the
exception of the arm lock shafts, spring pins are always shorter than the diameter of the
shaft. The procedures for removal and replacement of spring pins are as follows:
SPRING PIN REMOVAL:
1. Look at the exploded view of the machine in the parts section and find the size of the
pin.
2. Using the proper size drift punch, tap the pin into the shaft until the pin is completely
out of the bracket or collar.

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3. Remove the shaft from the bracket or the collar from the shaft, and tap the spring pin
through and out of the shaft. NOTICE: ALWAYS REMOVE THE PIN FROM THE
SHAFT IMMEDIATELY. ACCIDENTAL INSTALLATION OF A SECOND PIN
WILL DAMAGE THE MACHINE.
SPRING PIN REPLACEMENT:
1. Check the hole in the shaft to make sure the old pin has been removed. Assemble the
shaft in the bracket or grip collar on the shaft.
2. Tap the new spring pin into the bracket or collar until the end of the pin is flush with
the outside. Be careful not to damage chrome.
NOTICE: SEE THE SPECIAL INSTRUCTIONS, ADJACENT TO THE PARTS LIST
FOR THE ROLL PIN INSTALLATION ON THE FOLLOWING MACHINES:
SQUAT, MILITARY PRESS, SHOULDER SHRUG, LAT PULL DOWN, AND LEG
PRESS.
TOOLS REQUIRED: large screwdriver, 5/16 drift punch and a hammer
The seated Chest Press, Military Press, Tricep, Upper Back and Leg Press use a steel
shaft to lock the exercise arms together for bilateral exercise. If this shaft must be
removed for any reason, follow this procedure.

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REMOVING THE SHAFT:
1. Pry off the plastic cap covering the locking sleeve and spring pin. On the Seated
Chest Press and Upper Back, this is the middle of the three square tubes. On the
Military Press and Tricep, it is the outside tube. This cap must be replaced with a new
part. NOTICE: BE CAREFUL NOT TO SCRATCH THE CHROME.
2. Pry off the white plastic locking sleeve with a screwdriver.
3. Using a 5/16 drift punch, drive the spring through and out of the shaft. The shaft and
spring pin can now be removed.
REPLACING THE SHAFT:
4. Put the shaft back into holes in the exercise arms.
5. Drive the spring pin through the shaft until it is just flush with the side of the shaft
facing you.
6. Push the locking sleeve over the shaft.
7. Using a rubber mallet or block of wood and hammer, drive a new plastic cap into the
end of the square tube.