Can’t find your part?   Contact us:
+1-309-603-4777
Sears Parts Direct
Tips to find your model number
Orders

  • Keep track of the models you own in your profile

    Sign in or Register to view or add models

Schedule a repair
Craftsman
Riding Mowers & Tractors

Model # 3904 Official Craftsman lawn tractor

Here are the diagrams and repair parts for Official Craftsman 3904 lawn tractor, as well as links to manuals and error code tables, if available.

There are a couple of ways to find the part or diagram you need:

  • Click a diagram to see the parts shown on that diagram.
  • In the search box below, enter all or part of the part number or the part’s name.

Not all parts are shown on the diagrams—those parts are labeled NI, for “not illustrated”.

We encourage you to save the model to your profile, so it’s easy to access parts and manuals for your appliance whenever you log in.

For DIY troubleshooting advice and repair guides, visit our repair help section.

Model diagram and schematic

SEARCH WITHIN THIS MODEL

?

This is the number corresponding to the part on the diagram / schematic

Search
ALL PARTS
Showing 10 of 758 parts  |
Lever 12181-5717-0
#40

Speed control plate - starter diagram

Lever

Part #12181-5717-0

The manufacturer no longer makes this part, and there's no substitute part

Cover 12181-7550-0
#70

Fan cover diagram

Cover

Part #12181-7550-0

The manufacturer no longer makes this part, and there's no substitute part

Gasket 12181-1452-0
#30

Head cover - camshaft diagram

Gasket

Part #12181-1452-0

The manufacturer no longer makes this part, and there's no substitute part

Crankshaft 12181-1354-0
#70

Crankcase - cylinder head diagram

Crankshaft

Part #12181-1354-0

The manufacturer no longer makes this part, and there's no substitute part

Lever 66071-5517-0
#80

Dashboard diagram

Lever

Part #66071-5517-0

The manufacturer no longer makes this part, and there's no substitute part

Lawn Mower Bushing 58511-2812-0
#240

Front axle diagram

Lawn mower bushing

Part #58511-2812-0

The manufacturer no longer makes this part, and there's no substitute part

Cover 66071-5122-0
#60

Frame diagram

Cover

Part #66071-5122-0

The manufacturer no longer makes this part, and there's no substitute part

Spring 66071-4286-0
#240

Brake pedal diagram

Spring

Part #66071-4286-0

The manufacturer no longer makes this part, and there's no substitute part

Shaft 12181-5610-0
#100

Governor diagram

Shaft

Part #12181-5610-0

The manufacturer no longer makes this part, and there's no substitute part

Bolt 66071-5547-0
#30

Battery diagram

Bolt

Part #66071-5547-0

The manufacturer no longer makes this part, and there's no substitute part

Most common symptoms to help you fix your riding mowers & tractors

Choose a symptom to see related riding mower and lawn tractor repairs.

View all

Why is my riding mower not cutting evenly?

Main causes: unlevel mower deck, dull or damaged cutting blades, worn mandrel pulleys, bent mower deck, engine needs tun…

Read more

Why won't my riding mower start?

Main causes: dead battery, stale fuel, bad starter solenoid, ignition system problem, bad ignition interlock switch, clo…

Read more

Why is the steering loose on my riding mower?

Main causes: damaged tie rods, bent or worn wheel spindle, worn front axle, damaged sector gear assembly…

Read more

How do I fix a flat tire on my riding mower?

Main causes: punctured tire or inner tube, leaky valve stem, damaged wheel rim…

Read more

Why won't my riding mower cut grass?

Main causes: worn or broken blade belt, broken belt idler pulley, blade clutch cable failure, bad PTO switch, damaged ma…

Read more

How do I charge a dead battery on my riding mower?

Main causes: faulty battery, bad alternator…

Read more

Why does my riding mower deck vibrate?

Main causes: damaged cutting blade, worn deck pulley, damaged mandrel pulley, loose fasteners on mower deck components…

Read more

Why does my riding mower creep in neutral?

Main causes: shift lever needs adjustment, neutral control needs adjustment…

Read more

Why won't my riding mower move?

Main causes: worn or broken ground drive belt, bad seat switch, transaxle freewheel control engaged, transaxle failure, …

Read more

Most common repair guides to help fix your riding mowers & tractors

These step-by-step repair guides will help you safely fix what’s broken on your riding mower or lawn tractor.

View all
How to replace the starter motor on a riding lawn mower

How to replace the starter motor on a riding lawn mower

If you hear the solenoid click but don’t hear the starter motor spin when you turn the key, follow these steps to replac…

Read more
Repair difficulty
Time required
 30 minutes or less
How to rebuild a riding lawn mower carburetor

How to rebuild a riding lawn mower carburetor

Get your sputtering carburetor running smoothly in 60 minutes.…

Read more
Repair difficulty
Time required
 60 minutes or less
How to replace a riding lawn mower rear tire

How to replace a riding lawn mower rear tire

Your mower can’t run on a damaged rear tire. Here’s how to install a new one.…

Read more
Repair difficulty
Time required
 60 minutes or less

Effective articles & videos to help repair your riding mowers & tractors

Use the advice and tips in these articles and videos to get the most out of your riding mower or lawn tractor.

View all
How to enjoy all the online benefits we offer on our Sears PartsDirect website

How to enjoy all the online benefits we offer on our Sears PartsDirect website

Learn about all the convenient features on our Sears PartsDirect website that make your parts purchases easier.…

Read more
Top questions about Sears and Sears PartsDirect

Top questions about Sears and Sears PartsDirect

Get answers to frequently asked questions about Sears and Sears PartsDirect.…

Read more
Riding lawn mower engine clicks but doesn't turn over video

Riding lawn mower engine clicks but doesn't turn over video

Check the starter solenoid, starter motor, wiring, battery and engine.…

Read more

Parts & More