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Buyers Products 2" Forged SAE Trailer King Pin with 3/8" Bolster Plate - Weld On
Buyers Products

Buyers Products 2" Forged SAE Trailer King Pin with 3/8" Bolster Plate - Weld On

Part Number: 337KP20038
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$83.16
Retail:$111.99
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5th Wheel Pin Box
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Buyers Products 5th Wheel Pin Box - 337KP20038

  • King Pin Only
  • Buyers Products


Buyers Products 2" Forged SAE Trailer King Pin provides strength and reliability in coupling your fifth wheel. Forged from AISI 8630 steel and heat treated to maintain a hardness of 302-363 BHN and 150,000 PSI in ultimate strength. The King Pin has a 3/8" thick bolster plate and a 3" bolster plate hole thickness.


  • Forged from AISI 8630 Steel
  • Heat treated to create and maintain a hardness of 302-363 BHN
  • 150,000 P.S.I. in ultimate strength
  • Bolster plate thickness: 3/8"
  • Bolster plate hole thickness: 3"
  • Forged steel construction
  • Plain finish
  • Made in the USA

KP20038 Buyers Products 2 Inch Forged SAE Trailer King Pins With 3/8 Inch Bolster Plate - Weld On





Video of Buyers Products 2" Forged SAE Trailer King Pin with 3/8" Bolster Plate - Weld On

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.




Video Transcript for Buyers Products Fifth Wheel King Pin - Universal King Pin - 337KP20038 Review

Speaker 1: Now, we're gonna take a look at the two inch forged SAE Trailer King Pin with the 3/8 inch thick bolster plate. Now, this trailer King Pin will provide strength and reliability in coupling your fifth wheel. It is made of a forged steel construction. It's forged from AISI8630 Steel. It is heat treated to create and maintain a hardness of 302-363 BHN. It is 150,000 PSI in ultimate strength.

The bolster plate, up at the top here, the diameter on that, edge to edge, is right at eight inches. The bolster plate thickness is 3/8 of an inch. And then the bolster plate hole thickness, which is the portion right here, is three inches diameter. This part is made in the USA. The two inch measurement is the diameter right down here of your King Pin.

That should do it for the review on the Two Inch Forged SAE Trailer King Pin with the 3/8 inch thick bolter plate.

Customer Satisfaction Score:


Customer Reviews

Buyers Products 2" Forged SAE Trailer King Pin with 3/8" Bolster Plate - Weld On - 337KP20038

Average Customer Rating:  4.8 out of 5 stars   (69 Customer Reviews)


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Fast good service



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got my order fast



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I have been using these for years from a different supplier.



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Great thanks



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great product



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Worked great



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See what our Experts say about this Buyers Products 5th Wheel Pin Box

  • Troubleshooting Short King Pin on a 1972 5th Wheel Trailer
    It sounds like you have an older 5th wheel pin box and you need to either replace the king pin or replace the entire pin box. To replace the king pin you most likely would need a weld-on option like the Buyers # 337KP20038 which has a 3/8" bolster plate. If you would rather go with a bolt-on option then we do have part # 337BKPT809B but you need to make sure that you pin box is in excellent condition to ensure that this will hold up properly. We do carry replacement pin boxes as well...
    view full answer...
  • Availability of King Pin that Can Be Used to Close Jaws of Fifth Wheel Hitch
    We have metal king pins you could use like the part # 337KP20038 to close your hitch jaw when not in use, but the king pins you see in our review videos is actually a plastic king pin we don't offer for sale. The # 337KP20038 is 13 lbs which wouldn't be too heavy to use in your application.
    view full answer...
  • Why Do King Pin Replacements Have Different Bolster Thicknesses
    King pins can be found on a variety of different trailer types; 5th wheel, gooseneck, RVs, campers, lawncare, excavating, and car haulers just to name a few. So if you're just replacing the king pin you will want to use one that has a matching bolster plate thickness: 1/4" - # 337KP20025 5/16" - # 337KP20031 3/8" - # 337KP20038 1/2" - # 337KP20050 Attached is a review video for you to check out.
    view full answer...
  • Weight of Buyer's Products Forged Trailer King Pin 337KP20038
    The Buyer's Products Forged Trailer King Pin, part # 337KP20038 weighs 11 lbs with a shipping weight of 13 lbs.
    view full answer...
  • Fit & Compatibility of Convert-A-Ball 5th Wheel Trailer to Gooseneck Trailer Hitch Adapter
    The Convert-A-Ball 5th wheel to gooseneck is not specific to a trailer, it will fit on 2 inch industry standard king pins, like the Buyers Products # 337KP20038. It will then couple to a standard 2-5/16 inch gooseneck ball. To determine if the 12 to 16 inch height range of the # CAB-C5G will work you can follow the following procedure: After backing the vehicle under the trailer, measure from the top of the ball in the truck bed to the base of the pin box on the trailer. This will indicate...
    view full answer...
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  • Replacement King Pin Rebuild Kit Availability
    I am not sure if there are specialists that can repair your king pin but we do have a variety of replacement king pins for you to choose from. If you check out the linked page you can see options like the Buyers Products # 337KP20038 which is a universal replacement king pin. These do need to be installed by a professional welder.
    view full answer...

Do you have a question about this 5th Wheel Pin Box?


Info for this part was:

Employee Mike L
Expert Research:
Mike L
Employee Jameson C
Expert Research:
Jameson C
Employee Lindsey S
Edited by:
Lindsey S
Employee Jeff D
Installed by:
Jeff D
Employee Kristina F
Written by:
Kristina F

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