Craftsman 106173781 twin-cylinder tank-type air compressor Parts

For a Craftsman twin-cylinder tank-type air compressor like model 106173781, the model number is typically printed on a data plate or sticker attached to the tank or frame; it’s often near the handle, base, or where the power cord and controls are mounted.

Where to look on a tank-type air compressor

Check these common spots first:

• Tank: front, side, or near the bottom seam
• Frame/base: near the feet or wheel bracket area
• Motor/pump area: on the shroud or nearby bracket (less common than the tank)
• Control panel area: near the pressure switch, regulator, or gauges
• Back side of the unit: especially if the front is kept “clean” for branding labels

What the label usually includes (and what to write down)

On most compressors, the same label includes multiple identifiers. Record them exactly as shown.

Label item	What it’s used for	Example of what it looks like
Model number	Matching the correct parts list	106173781
Serial number	Production run identification	Letters and numbers
Electrical rating	Confirming power requirements	Volts/amps/Hz
Pressure rating	Confirming safe operating limits	PSI / kPa

Tips if the label is missing or unreadable

If the sticker is scraped off or painted over, these steps help you recover the model number:

• Wipe the area with a damp cloth; dirt can hide faint printing
• Shine a flashlight across the surface at a low angle to reveal embossed text
• Look for a second label on the opposite side of the tank
• Check for a stamped number on the tank collar or frame plate
• Use your parts search history and saved appliances in Sears PartsDirect if you previously looked it up

Why it matters

The model number is what ties your compressor to the correct parts diagrams and compatible components (such as pressure switches, regulators, safety valves, and check valves). Using the exact model number prevents ordering parts that fit a similar-looking Craftsman unit but won’t match your build.

Last updated: February 2026

4.0 SCFM at 90 PSI means the compressor can supply 4 standard cubic feet of air per minute while delivering 90 PSI at the outlet. It is a performance rating used to match an air compressor to pneumatic tools; it is not automatically the confirmed rating for every Craftsman model.

How to use 4.0 SCFM @ 90 PSI to pick tools

Use the tool’s air requirement label (often listed as SCFM at 90 PSI) and compare it to the compressor’s SCFM rating at the same pressure.

• If the tool requires 3.0 SCFM @ 90 PSI, a 4.0 SCFM @ 90 PSI compressor runs it steadily
• If the tool requires 5.0 SCFM @ 90 PSI, the compressor falls behind; pressure drops during use
• Add 25% to 50% extra SCFM for smoother operation on continuous-use tools
• Set the regulator to the tool’s required PSI; higher PSI wastes air and increases cycling
• Use a larger hose (commonly 3/8-inch for higher-flow tools) to reduce pressure drop

SCFM vs CFM (what “standard” changes)

SCFM is measured under standardized conditions so you can compare compressors more fairly. CFM can be reported under varying conditions and is less useful for tool matching.

Spec	What it tells you	What to do with it
SCFM @ 90 PSI	Usable airflow at a common working pressure	Primary number for most air tools
SCFM @ 40 PSI	Airflow at lower pressure	Helpful for some nailers/sprayers
PSI	Pressure capability	Must meet the tool’s minimum PSI

Why it matters

Air tools need pressure (PSI) and volume (SCFM). PSI is the push; SCFM is the amount of air available to keep the tool running without bogging down.

Related DIY help

If you are troubleshooting a compressor that will not start, trips a breaker, or runs weak, electrical testing is often the first step; use how to use a multimeter to test electrical parts video.

Last updated: February 2026

Most air compressors last about 10 to 15 years with normal use and basic maintenance; smaller DIY units often run 5 to 10 years, while heavier-duty shop and industrial compressors commonly reach 15 to 20 years. For a Craftsman 106173781 twin-cylinder tank-type air compressor, lifespan depends most on duty cycle, heat, moisture control, and leak-free operation.

Typical lifespan by compressor type

Compressor type	Typical lifespan	Notes
Small DIY / homeowner (portable)	5 to 10 years	Shorter life if run hot or continuously
Twin-cylinder tank-type (like 106173781)	10 to 15 years	Often limited by pump wear, valves, and tank condition
Industrial rotary screw / centrifugal	15 to 20 years	Designed for continuous duty with scheduled service

What shortens lifespan fastest

• Running past the duty cycle (long continuous run time that overheats the pump)
• Moisture left in the tank (internal rust and contaminated air)
• Air leaks in fittings, hose connections, or the check valve (extra run time)
• Dirty intake filter (restricted airflow and higher operating temperature)
• Low or degraded pump oil on oil-lubricated designs (accelerated wear)

Maintenance that adds years (high impact)

• Drain the tank after use or at the end of the day to remove condensation.
• Keep the intake area clean; replace or clean the air filter on schedule.
• Check for leaks (listen for hissing; use soapy water on fittings).
• Keep ventilation clear so the pump and motor can shed heat.
• If your unit is oil-lubricated, keep oil at the correct level and change it at regular intervals.

When it is time to repair vs. replace

Symptom	Usually worth repairing	Usually points to end-of-life
Slow build to pressure	Leaks, dirty filter, worn reed/valves	Severe pump wear plus multiple leaks
Frequent cycling	Small leaks, pressure switch issues	Tank corrosion causing recurring problems
Loud knocking	Loose hardware, minor wear	Persistent knock with low output

Why it matters

A compressor that runs longer to reach cut-out pressure builds heat and moisture faster; that speeds up pump wear and increases rust risk in the tank. Keeping run time down and water out is the simplest way to extend service life.

For safe DIY electrical checks (motor, pressure switch, capacitor), use our how to use a multimeter to test electrical parts video.

Last updated: February 2026

For the Craftsman 106173781 twin-cylinder tank-type air compressor, the most common cause of failure is poor maintenance that leads to overheating and accelerated wear (dirty intake filter, low or degraded oil on oil-lubricated units, and restricted cooling airflow). Air leaks and electrical issues are also frequent contributors.

Most common failure drivers (and what to check first)

• Overheating: clogged cooling fins, blocked shroud/guard, poor ventilation, long run times.
• Dirty or restricted intake filter: makes the pump work harder and run hotter.
• Lubrication problems (if oil-lubricated): low oil level, wrong oil type, old oil.
• Air leaks: fittings, drain valve, pressure switch line, tank check valve area.
• Electrical problems: weak power supply, damaged cord, failing pressure switch, bad capacitor (if equipped).

Quick symptom-to-cause guide

Symptom	Most likely cause	What we do next
Runs hot, shuts off, or trips breaker	Overheating or electrical overload	Improve airflow, reduce duty cycle, verify outlet/circuit
Runs constantly, won’t reach cut-out	Air leak or worn pump valves/rings	Leak test, then evaluate pump condition
Hard start or hums then trips	Capacitor/motor issue or low voltage	Check voltage, inspect wiring, test electrical parts
Builds pressure slowly	Intake restriction or worn pump	Check filter and airflow, then pump wear

Why it matters

Heat and friction are what kill compressors. When airflow is restricted or lubrication and filtration are neglected, internal temperatures rise, seals and valves wear faster, and the motor draws more current. Fixing the root cause early prevents repeat failures.

Practical prevention for this model type

• Keep the compressor in a clean, well-ventilated area; do not block the pump or motor.
• Drain tank moisture regularly to reduce corrosion and water carryover.
• Check and tighten fittings; use soapy water to find small leaks.
• If your unit is oil-lubricated, keep oil at the proper level and change it on a routine schedule.
• If you suspect an electrical issue, use safe test methods from how to use a multimeter to test electrical parts video.

Last updated: February 2026