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Craftsman
Front-Engine Lawn Tractor

Model # 9178420 Official Craftsman heavy-duty riding unit

Here are the diagrams and repair parts for Official Craftsman 9178420 heavy-duty riding unit, as well as links to manuals and error code tables, if available.

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Model diagram and schematic

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ALL PARTS
Showing 10 of 234 parts  |
Tire 6032H
#12

Main frame diagram

Tire

Part #6032H

Replaced by #532122075

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Manufacturer substitution
This part replaces 6032H. Substitute parts can look different from the original.
BEST SELLER
$73.61 | 
8% OFF Phone Price : $79.61
In Stock
Pin 786026
#50

Transmission diagram

Pin

Part #786026

Replaced by #786026B

?
Manufacturer substitution
This part replaces 786026. Substitute parts can look different from the original.
BEST SELLER
This item is not returnable
$4.60 | 
18% OFF Phone Price : $5.60
In Stock
Lock Washer 10040500
#53

Main frame diagram

Lock washer

Part #10040500

Replaced by #596238801

?
Manufacturer substitution
This part replaces 10040500. Substitute parts can look different from the original.
This item is not returnable
$5.11
In Stock
Washer 19252016
Washer

Part #19252016

Replaced by #532121749

?
Manufacturer substitution
This part replaces 19252016. Substitute parts can look different from the original.
This item is not returnable
$3.98 | 
20% OFF Phone Price : $4.98
In Stock
Ring 792001
#3

Transmission diagram

Ring

Part #792001

Replaced by #792001

?
Manufacturer substitution
This part replaces 792001. Substitute parts can look different from the original.
This item is not returnable
$4.37
In Stock
Screw 792007
#49

Transmission diagram

Screw

Part #792007

Replaced by #792007

?
Manufacturer substitution
This part replaces 792007. Substitute parts can look different from the original.
This item is not returnable
$4.37
In Stock
Gear 778036
#43

Transmission diagram

Gear

Part #778036

Replaced by #778036

?
Manufacturer substitution
This part replaces 778036. Substitute parts can look different from the original.
$70.64
In Stock
Gear 778039
#53

Transmission diagram

Gear

Part #778039

Replaced by #799023

?
Manufacturer substitution
This part replaces 778039. Substitute parts can look different from the original.
$119.68
In Stock
Seal 788009
#60

Transmission diagram

Seal

Part #788009

Replaced by #788009

?
Manufacturer substitution
This part replaces 788009. Substitute parts can look different from the original.
$11.60
In Stock
Gear 778037
#27

Transmission diagram

Gear

Part #778037

Replaced by #778037

?
Manufacturer substitution
This part replaces 778037. Substitute parts can look different from the original.
$53.09
In Stock

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

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

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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…

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

Main causes: faulty battery, bad alternator…

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

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

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Why won't my riding mower start?

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

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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…

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Why does my riding mower creep in neutral?

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

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Why does my riding mower run rough or misfire?

Main causes: clogged carburetor, damaged flywheel key, dirty spark plug, stale fuel, improper valve lash, engine needs a…

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Why won't my riding mower move?

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

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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…

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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.

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How to replace a mandrel assembly on a riding lawn mower

How to replace a mandrel assembly on a riding lawn mower

Replace the mandrel assembly if the blade shaft vibrates or doesn't spin.…

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Repair difficulty
Time required
 30 minutes or less
How to replace the flywheel key on a riding lawn mower

How to replace the flywheel key on a riding lawn mower

If the engine won't restart after hitting a stump or rock, the problem could be a sheared flywheel key. Follow these ste…

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Repair difficulty
Time required
 60 minutes or less
How to replace a riding lawn mower ignition coil

How to replace a riding lawn mower ignition coil

If you're not getting spark from a good spark plug, the problem could be the ignition coil. Follow these step-by-step in…

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Repair difficulty
Time required
 30 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.

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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.…

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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.…

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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.…

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