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New 8T4778 Locknut Unc Harde Replacement suitable for Caterpillar Equipment
- New Locknut Unc Harde Replacement suitable for Caterpillar Equipment
- Made to USA Specification
Buy with Confidence: All parts are covered by our warranty
Exact Fit Guarantee
This part is guaranteed to fit your machine.
Wrong Part?
We'll overnight correct part at no cost to you.
Description for 8T4778 Self-locking Nut
â–¶Specification for 8T4778 Self-locking Nut
â–¶Exact Fit Guarantee for 8T4778 Self-locking Nut
â–¶| Models | 1090, 1190, 1190T, 120H, 120M, 120M 2, 1290T, 12H, 12H ES, 12M, 12M 2, 12M 3, 12M 3 AWD, 1390, 140H, 140H ES, 140M, 140M 2, 140M 3, 140M 3 AWD, 143H, 14H, 14H NA, 14M, 160H, 160H ES, 160M, 160M 2 |
|---|---|
| Dimensions | 1.06x0.55x0.55 |
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The Double Order Catastrophe
My co-worker placed an order and wasn't sure it went through online. I later placed the same order thinking the previous order didn't go through. To my surprise both orders went through, and I needed to cancel one of the orders. I called and spoke with someone who instructed me someone would contact me about the situation. I was contacted by Misty and she said she would do her best to cancel one of the orders but not sure if she could because they were next day orders. A small tome later I received an email saying she was able to cancel one of the orders. Thank you to Misty and the entire Propel Parts Team. Greatly appreciated!! -
Very thorough ! Confirmed order and great communications.
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Excellant customer service!
The prices are very good! The customer service is excellant! I had to contact them because our tax info wasn't right and they refunded it on the spot! Great job! we will be doing a lot more ordering from thi company. Highly recommended! -
Great service at an affordable price to get my machine back going.
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Cat blade pins.
Easy transaction good web site.
Frequently Asked Questions
What is the 8T4778 UNC locknut and how is it used?
The 8T4778 is a hardened UNC locknut designed for use in Caterpillar equipment assemblies where vibration resistance is critical. For the full range of heavy equipment hardware parts including locknuts and specialty fasteners, visit our hardware category.
When should this locknut be replaced?
Replace the 8T4778 locknut if:
- The prevailing torque feature is no longer effective (nylon insert sheared or deformed)
- Thread damage prevents proper torque from being achieved
- Corrosion has compromised the nut's structural integrity
- The nut has been subjected to excessive torque that deformed the profile
Can I reuse this locknut?
Nylon insert locknuts (Nylock style) should not be reused ??? the nylon insert loses effectiveness with each subsequent use. All-metal prevailing torque locknuts can sometimes be reused if the threads show no damage, but replacement is always the safer choice.
Is the 8T4778 compatible with my Caterpillar machine?
Compatibility depends on thread size, pitch, width across flats, and hardness grade. For related assembly components, see our engine assembly parts. Verify using your equipment's service documentation.
What torque should I apply to this locknut?
Torque specifications for locknuts vary based on thread size, grade, and the assembly being fastened. Always refer to your Caterpillar service manual for the correct torque value.
Is this a quality aftermarket part?
Yes ??? the 8T4778 is a premium aftermarket locknut manufactured to meet or exceed OEM specifications for thread precision, hardness, and locking torque characteristics.
What warranty and shipping options does Propel Parts offer?
Propel Parts covers this part with a 12-month warranty from the invoice date. Same-day shipping is available for weekday orders placed before 3:00 PM ET, with worldwide delivery available.
This 8T4778 Self-locking Nut is compatible with the following models:
1090, 1190, 1190T, 120H, 120M, 120M 2, 1290T, 12H, 12H ES, 12M, 12M 2, 12M 3, 12M 3 AWD, 1390, 140H, 140H ES, 140M, 140M 2, 140M 3, 140M 3 AWD, 143H, 14H, 14H NA, 14M, 160H, 160H ES, 160M, 160M 2 & more...
Shipping
We know equipment downtime costs money, so fast and reliable shipping is a priority at Propel Parts. Orders placed on weekdays before 3:00 PM ET typically ship the same day, with expedited delivery options available for many locations when time is critical.
We ship across the U.S., Canada, and over 130 countries worldwide, helping customers keep machines running wherever they operate. Available shipping methods and delivery estimates are shown at checkout so you can select the option that best fits your timeline.
Tracking information is emailed within 24–48 hours after your order is processed, giving you full visibility from dispatch to delivery and peace of mind that your parts are on the way.
Easy Returns
Our refund policy is simple. We offer a 30-day, no-hassle return policy, and we make every effort to provide the best service and highest-quality parts possible. If you’re not fully satisfied with your purchase, you may return it within 30 days for a refund. Full details are available on our Returns Policy page.
Warranty
Buy with confidence. All parts from Propel Parts are covered against material or manufacturer defects for 12 months from the original invoice date. We stand behind every part we sell, so you can count on reliable performance and dependable support. Full details are available on our Warranty Policy page.
Exact Fit Guarantee®
The right part — or we'll make it right.
Order Normally
Know your part number? Simply place your order.
Not Sure?
Place your order, then send us your serial number before it ships.
We'll verify fit.
We Make It Right
Wrong part? We'll make it right.Fast. At our expense.
1 YEAR UNLIMITED WARRANTY
ORDER BY 3PM EST. EXCL. WEEKEND
NO CORE OR EXCHANGE CHARGES
EASY RETURNS & FAST REFUNDS
