Table of Contents

Operation of 8300 Series Pneumatic Screwdrivers
Tools Required for Repairing 8300 Series Pneumatic Screwdrivers
Lubrication for 8300 Series Pneumatic Screwdrivers
Lubrication Instructions for Repair and Maintenance
Troubleshooting Guide

Operation of 8300 Series Pneumatic Screwdrivers

The following guidelines are provided to insure safe operations of Standard Pneumatic's 8300 Series Pneumatic Screwdrivers.

  • Always operate, inspect, and maintain any tool in accordance with American National Standards Institute Safety Code for Portable Air Tools (ANSI B1869.1)

  • For safety, top performance and maximum durability of parts, operate these tools at 90 psig(6.2bar/620 kPa) maximum air pressure at the inlet with 1/4" (6mm) ID air hose.

  • Always turn off and disconnect the air supply before installing, removing, or adjusting any accessory on this tool, or before performing any maintenance or repair.

  • Keep hands, loose clothing, and long hair away from the rotating end of the tool.

  • Anticipate and be alert for sudden changes in motion during start up and operation of any power tool.

  • Standard Pneumatic is not responsible for damage caused by any customer modifications of tools.

  • Always use clean, dry air. Dust, corrosive fumes or excessive moisture can damage the motor of an air tool. An air line filter and lubricator are required.

  • Low or fluctuating air pressure causes variations in tool speed and can result in inaccurate torque values.

Tools Required for Repairing 8300 Series Pneumatic Screwdrivers
  • Crescent Wrench - jaw opening to 1 1/8"

  • Vise - bench model or portable

  • Retaining ring pliers - internal & external

  • Open end wrenches - 3/8 & 3/4

  • Hex wrenches - .050, 7/64 & 1/4

  • Small Hammer & Strap wrench

  • Punch (3p or similar)

  • Micrometer - 1 to 2"

  • Small arbor press

  • Flat plate (glass or other)

  • Emery cloth

  • Tachometer

  • Container (at least 6" wide with low walls)

Lubrication for 8300 Series Pneumatic Screwdrivers

The ideal air supply to our tools can be achieved with our model 280 Filter-Regulator-Lubricator. The filter element removes contaminating solids, oils and liquids which may be in the compressed air line whether newly installed or not. This filter unit is equipped with a petcock for "dumping" the contaminants without shutting off the air supply.

The regulator controls the air supply to maintain a constant pressure at the tool even though there are changes in the flow demand and or inlet pressure.

When other manufactures of lubricators are used, it is recommended that the customer check with that particular manufacturer for the proper procedure for setting the lubricator to deliver 1/10 of a drop per minute to the tool. Many lubricators, especially larger units, require high airflow rates for the lubricator to operate properly. Therefore, the manufacturer should also be asked to verify the operation of the lubricator at a 10 cfm flow rate for the 8000 series.

Multiple tools on one air system present another problem. When several tools are connected to the same lubricator, it is not possible for the correct amount of lubrication to go to each tool. Since it is highly unlikely that the same number of tools would also be in operation at the same time, the airflow through the lubricator would be a variable; thus the amount of lubrication put into the airflow would also vary. However, with the micro fog type of lubricator, such as our model 280, the oil particle size is such that the oil stays suspended in the air through several "takeoffs" better than with other types of lubricators without wetting out. This results in multiple tools on the same line being better lubricated.

The position of the various tools in the system in relation to the distance away from the lubricator would also cause a variance in the amount of lubrication to each tool. If several tools must be connected to the same lubricator, the same procedure for setting the amount of lubrication on the unit should be used with only one of the tools running. It is assumed that the increased airflow of several tool operating at the same time will pull more oil into the system. The maximum number of tools that we recommend connected to one model 280 is two.

Lubrication Instructions for Repair and Maintenance

1. 1. Use Standard Pneumatic Tool Lubricant (part number 100) or a S.A.E. 10 wt non-detergent oil for lubricating the motor.

2. Generously lubricate rotor and rotor blades prior to reassembly of the motor.

3. Lightly coat all idler gears, pins on the gear plate assemblies and pinion gears with Darina AX multifuse grease or equivalent.

Trouble Shooting Guide


Possible Cause

Tool will not run or stalls

*Air pressure must be at 90psig (6.2bar/620kPa)
*Missing or broken rotor blade
*Lock nut on rotor is not correctly adjusted
*Burrs on gears
*Front or rear plate scored
*T-Valve installed incorrectly -Trigger is to be pulled
  completely out prior inserting T-Valve into housing.

Loss of power

*Lack of lubrication
*Muffler elements clogged
*Air pressure must be at 90psig (6.2bar/620kPa)
*Inlet screen clogged
*Rotor blades installed backwards
*Bearings worn

Tools stalls before clutch trips

*Clutch adjustment
*Air pressure must be at 90psig (6.2/620kPa)
*Rated tool performance vs torque requirement
*Damaged clutch component

Tool will not restart after clutch trips

*Push rod not at correct length or bent
*Burrs on gears
*Badly worn rotor
*Spring on upper clutch spindle broken or damaged


NOTE: Whenever a 8300 series tool is to be placed in a vise, use leather or copper covered jaws to protect the surface of the housing or tool and help prevent distortion. This is especially true of motor housings and threaded portions of the housing. Distortion of the motor housing could result in irreparable damage. (Numbers in parentheses refer to numbered parts in parts drawing)

1. Grasp the tool and remove the clutch housing (3) by turning the housing clockwise (left hand threads). If the clutch housing will not unscrew by hand then grasp the tool in a padded jaw vise and use a strap wrench to loosen the housing. Remove the clutch from motor housing assembly, taking special care not to bend the push rod (70).

2. Place the drive end of the tool into a vise, taking special care not to bend the push rod. Clamp onto the flats of the internal gear (34), then turn the pistol housing clockwise (left hand threads) to loosen. Remove the from the vise and continue turning the internal gear (34) until it separates from the housing. Carefully tilt the housing downward causing the gear train and motor to slide out.
Note: Place the motor and gear assemblies in a shallow container and clean all parts with solvent or alcohol after they have been disassembled.

3. Using an internal retaining ring pliers remove the retaining ring (32) from the internal gear (47). To remove the bearing and output spindle assembly (33, 35) from the internal gear, use a pencil or rod to push on the gear pins side of the output spindle (35). Check the bearing (33) for wear and smooth rotation. If the bearing requires replacement remove retaining ring (27) from output spindle (35), then press the output spindle away from the bearing.

4. Grasp the splined end of the rotor (47) firmly, unscrew the lock nut (52) by turning counter-clockwise. Then remove the bearing (51), rear plate (50), cylinder (48) and rotor blades (46) from rotor. Then using a snap ring pliers remove the retaining ring (42) from the splined end of rotor. Slide the bearing (43), wave washer (44) and front plate (45) from rotor.

5. Check bearings for excessive side play and smooth rotation. Inspect the front and back plates along with the rotor for any scoring or excessive or excessive wear. Inspect all idler gears (38,37) and pinion gears (40, 41) for burrs, chips and excessive wear. Place idler gears on the pins of the gear plate (39) and output spindle assembly (35), rotating easch one making sure it turns smoothly.

6. To remove push rod (70) place a 1/4" hex wrench into the end cap (76) turn clock- wise (left hand threads) to loosen. Using an internal retaining ring pliers or pointed rod to turn the retaining ring (74) and strainer (73) side ways to remove. Remove ring and strainer taking special care not to loose the spring (72) and valve ball (71). Remove push rod and visually inspect for straightness. Replace if rod cannot be straightened. Remove reverse valve using a rod or pencil to push it through the valve housing (66). Inspect the o-rings (67,69) and replace if worn.

7. Using an adjustable wrench, unscrew inlet fitting (82) by turning counter-clockwise. Remove compression spring (80), and butt plate (81). The T-valve (79) will drop once the spring is removed. A small metal rod about the same diameter as the push rod, bent into a hook shape at one end, can be used to remove the T-valve seat (77) and o-ring (78). Visually check the o-ring for wear. Using a needle nose pliers remove the internal muffler (84) from housing, wash wash muffler with suitable cleaning solution and thoroughly dry.

8. The trigger rod button (54), trigger rod bushing (57) and trigger rod (59) are held in the pistol housing (61) by a 1/16 dia. X 3/8 roll pin. Using a pin punch and hammer, carefully drive the pin is removed. The roll pin is located next to trigger and can be accessed from either side of housing. Remove trigger and assembly from housing. To remove trigger button (54) from trigger rod (59) use a .050 hex key to loosen set screw (55). O-rings (56,58) should be replaced if air leakage occurs when trigger is actuated.

9. The clutch assembly can be disassemblied by removing the retaining (25) ring from clutch spindle (15), then place a #2 phillips screwdriver into the notch located in the bearing ring washer (23), turn the driver counter clock-wise to loosen the adjustment nut (24). Releasing the spring compression will aid in disassemblying the clutch.

10. Place a container under the assembly to catch any of the steel balls that are to be removed. Cleaning the grease from the assembly will help in removing the steel balls. Remove the eight steel balls (9), 3 steel balls (10) and using a magnet will help in removing the eighteen steel balls (18). The clutch cam will separate from the clutch spindle (15). They will be a thrust washer or washers (12), see parts list for quantity depending on which model of tool. The small steel ball (10) and spring (14) may fall when cam is separated from spindle, then remove the lever (13) and pin (16).

11. Clean all parts thoroughly, using cleaning solvent, acetone, or an ultrasonic cleaner with specified soap.


Note: Whenever grasping a tool or part in a vise, always use leather-cover or copper-covered vise jaws. Always clean every part and wipe every part with a thin film of oil before installation. Apply a film of O-ring lubricant to all o-rings before final assembly.

1. If the bearing (33) on the output spindle (35) required replacement then press the new bearing onto the output until it bottoms on the shoulder. Use a snap ring pliers to secure the retaining ring (27) into the groove on spindle. Place the internal gear housing (34) so the internal gear is facing downward. Insert the output spindle/bearing into the internal gear housing, then install retaining ring (32) into the recessed groove of the housing, making sure the star washer (36) is secure in the I.D. of the spindle.

2. Apply a light coat of recommended grease to the pinion, idler gears and idler pins. Insert the pinion gear (40) into the gear plate assembly (39), then place the idlers gears (38,41,43) on the pins of the gear plate assembly and output spindle assembly (35). Install the idler/pinion gears into the internal gear housing (34) with the pinion gear end first. Rotate the gear assembly so the teeth of the gears mesh with the teeth of the internal gear. NOTE: The pinion gear (41) is installed onto the spindle gear of motor. Check the parts list for additional items depending on which model of tool is being repaired.

3. Assemble the motor by first placing the front plate (45) over the splined shaft of rotor (47) followed by the wave washer (44), then the bearing (43). Using an external snap ring pliers place the retaining ring (42) in the groove on the splined shaft. Note: the cylinder (48) has a U-shaped notch on one end. Place the cylinder, with the U-shaped notch end up, over the rotor against the front plate (45).

4. Wipe each rotor blade (46) with a light film of oil and place a blade in each slot of rotor (47) with the curved side facing to the center. Insert the alignment pin (49) into the small center hole located between the notched port holes. Install the rear plate (50) with the bearing recess away from cylinder and the top center hole aligned with dowel pin that had been placed in the end of the cylinder.

5. Install the bearing (51) in the recess of the rear plate followed by placing the lock nut (52) onto the threads of the rotor shaft, then hand tightened (the lock nut may turn only a 1/2 to 1 revolution). Assemble the motor to the internal gear housing containing the output shaft and idler gear assemblies .

6. Place the motor/gear train and internal gear housing in a V-Block, insert a 1/4" hex wrench into the hex opening of the output shaft. Place a 3/8" open end wrench on the lock nut of the motor assembly. Tighten the lock nut until a continuous drag is present when motor is rotated, then loosen the nut until the motor will rotate freely. Remove the motor assembly from the gear train, while holding the motor with one hand turn the splinded end of rotor. It should spin or rotate with out any evidence of tightness or dragging.

7. Place o-ring (78) onto the T-valve insert (77), then using a rod slide the insert with o-ring into the threaded inlet port, making certain that they have been fully seated. Insert the internal muffler into the non-threaded exhaust port until flush with end of housing. The T-Valve is placed with the shaft end first into inlet port and when properly installed the shaft can be visually seen when looking into the trigger port. Insert the compression spring (80) in inlet hole then attach the butt plate. Insert the inlet fitting through the opening of the butt plate into the threaded inlet port of housing, using an adjustable wrench turn the fitting clock- wise until securely tightened.

8. Install new o-rings (56,58) on the trigger rod bushing (57). Slide the trigger rod/disc (59,60) through the open end of bushing making sure the flat on the rod faces the set screw opening in the rod button (54). Using a .050 hex wrench, tighten the set screw (55). Insert the bushing and rod into the slot opening on the front of the handle. Press the trigger button until it bottoms out in housing, using a pin punch and hammer drive the 1/16 dia. x 3/8 long roll pin into the small hole located on side of housing near the trigger port. The roll pin locks the trigger assembly in place.

9. Installation of the dowel pin (65) into the valve housing (66) is somtimes tricky due to the smallness of the pin and the depth of the bore where the valve housing is located. The difficult part is having the pin stay in the motor assembly when inserted into bore. Install valve adapter (53) with the recess towards the lock nut on end of motor assembly and align the small center hole with the pin extending from end of motor. Apply some grease to the end of the dowel pin (65) prior to inserting into the small hole of the valve adapter that contains the other alignment pin. The grease will aid in holding the pin in place.

10. Hold the housing with handle upward, then slide the motor with valve adapter into the bore. A thin screwdriver or rod placed through the rear of the housing into one of the porting holes in the valve adapter will help to rotate the motor assembly so the align pin will slide into dowel pin hole of the valve housing. The motor and valve adapter should be flush with valve housing when properly assembled.

11. Insert internal gear housing (34) and geartrain into bore, rotation of the output shaft may be required so the gears properly mesh. Using an adjustable wrench placed on flats of internal gear, turn counter clockwise to tighten. Then use a crowfoot torque wrench tighten to 200 inch lbs.

12. Insert push rod (70) into reverse valve (68), followed by the valve ball (71), valve spring (72), strainer (73) and then retaining ring (74). Install new o-ring (69) to reverse valve and slide o-ring (67) onto the push rod until it is seated in the recess of the reverse valve. Carefully insert pushrod and reverse valve through the opening in the valve housing (66) guiding the rod into the hole that passes through the locknut, motor and gear train assemblies. Rotate the reverse valve so the threaded hole is centered in the slot at the top of the tool. Place the reverse valve cover (63) with set screw (64) in the groove located on the top of the housing where the slot is located. Then tighten the set screw and verify that the reverse valve will move freely from forward and reverse. Place the end cap (76) with o-ring (75) into the back end of housing, turning clockwise to tighten.

13. Install the clutch into the tool, then thread the clutch housing onto the tool by turning counter clockwise unit the clutch housing is tight against the motor housing. Be careful not to over-tighten or cross thread the clutch housing.

14. Attach the tool to an airline and check the free speed (RPM) with a tachometer. If required, the internal gear housing (34) may have to be loosened and then re-tightened until the optimal free speed is achieved. Ideally, the RPM should be as shown below:

Ideal RPM Values
for Model #


1600 RPM


1000 RPM


600 RPM


350 RPM


1600 RPM


1000 RPM


600 RPM


350 RPM

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