Measuring to Determine the Correct Replacement Pin Box for a 5th-Wheel Trailer

If you cannot locate the OEM pin box manufacturer's name and model number of your trailer's 5th wheel king pin box, you can measure it to find a correct replacement.

Step 1.

First, select the pin box style from the drawings below that matches the pin box on your 5th wheel trailer.

Step 2.

Next, after you have selected your pin box style, "Click" on the drawing below that matches it. Then print out the drawing and take it to your trailer. Use the drawing to measure the horizontal bolt hole distance, vertical bolt hole distance, bolt size, bolt head size, front row of bolts to king pin, back row of bolts to king pin and pin box width. Also, record the number of bolts per side that secure the pin box to the trailer frame.

Click on your pin box style to access a printable full size drawing.

Step 3.

Finally, use the pin box measurement chart to match the measurements of your trailer's OEM pin box to the manufacturer and model number. This will be the proper replacement pin box for your 5th wheel.

Note: Extending a pin box increases the amount of leverage applied to the frame of a 5th wheel trailer. Because this increased leverage can cause damage to a trailer frame, trailer manufacturers might not honor the trailer warranty if the pin box has been extended. Check with your trailer manufacturer if a new pin box will add more than 6" to the length of your original.

Pin Box Measurements
	Measurements	2a	2b	2c	2d	2e	2f	3a	3b	3c
	OEM Pin Box	Horizontal	Vertical	Center	Bolt Size	Bolt head Size	Bolt Qty per Side	Front Row to King Pin	Back Row to King Pin	Pin Box Width
Long	Fabex 665, M&M 665	7-5/8", 7-7/8"	2"	N/A	1/2"	3/4"	4	18-3/4"	26-3/8"	12"
	Venture CJ20515...17	8"	1-1/2"	N/A	1/2"	3/4"		18-1/2"	26-1/2"	12"
	Steelco/Davis PB02,PB02W	8"	1-1/2"	N/A	1/2"	3/4"	6	18-1/2"	26-1/2"	12"
	Fabex 765	9-1/2"	2"	4.75"	5/8"	15/16"	3	21-1/2"	31"	12-1/2"
	Fabex 750	9-1/2"	2"	4.75"	5/8"	15/16"	3	16"	25-1/2"	12-1/2"
	RBW 7028	9-1/2"	2-1/2"	N/A	5/8"	15/16"	2	20"	29-1/2"	12-1/2"
	Lippert 1621	7-7/8"	2"	N/A	5/8"	15/16"	6	17-3/4"	25-5/8"	12"
	Lippert 1621 HD	7-7/8"	2"	N/A	5/8"	15/16"	6	17-3/4"	25-5/8"	12"
	Fabex 500	9-1/2"	2-1/2"	N/A	5/8"	15/16"	2	20"	29-1/2"	12-1/2"
	Fabex 503	9-1/2"	2-1/2"	N/A	5/8"	15/16"	2	18"	27-1/2"	12-1/2"
	Lippert 1716	8-3/4"	2-1/2"	N/A	5/8"	15/16"	9	20-3/8"	29-1/8"	12-1/2"
	Leland 7920	7"	1-1/2"	N/A	1/2"	3/4"	6	21"	28"	14"
	Youngs Welding	9"	3"	N/A	3/4"	1-1/8"	4	20"	29"	12"
Medium	Fabex 730	9-1/2"	2-1/2"	4-3/4"	5/8"	15/16"	3	10-1/2"	20"	12-1/2"
	RBW 7019	9-1/2"	2"	N/A	5/8"	15/16"	2	13"	22-1/2"	12-1/2"
	Lippert 0719	7-7/8"	2"	N/A	5/8"	15/16"	6	9"	16-7/8"	12"
	Fabex 520	9-1/2"	2-1/2"	N/A	5/8"	15/16"	2	13-1/2"	23"	12-1/2"
	Fabex 530	9-1/2"	2-1/2"	N/A	5/8"	15/16"	2	11"	20-1/2"	12-1/2"
	Leland 7910	7"	1-1/2"	N/A	1/2"	3/4"	6	9"	16"	14"
	Youngs Welding	9"	3"	N/A	3/4"	1-1/8"	4	8"	17"	12"
	Lippert 1116	8-3/4"	2-1/2"	4-3/8"	5/8"	15/16"	9	14-5/8"	22-3/8"	12-1/2"
	Fabex 663, M&M 663	7-5/8", 7-7/8"	2"	N/A	1/2"	3/4"	6	9-1/2"	17-1/8"	12"
	Venture CJ13515, CJ13517	8"	1-1/2"	N/A	1/2"	3/4"	6	9-3/4"	17-3/4"	12"
	Steelco/Davis PB01	8"	1-1/2"	N/A	1/2"	3/4"	6	9-3/4"	17-3/4"	12"
Teles. 45 degrees	Youngs Welding Tube Style	7-1/8"	2-1/8"	N/A	1/2" or 5/8"	3/4" or 15/16"	5 (Retracted)	0"	10-3/4"	8"
Teles. 72 degrees	Atwood AB-72	7-7/8"	2"	N/A	1/2"	3/4"	4 (Retracted)	-1"	6-7/8"	12"
Teles. 72 degrees	RBW 7016-2P	7-1/4"	2"	N/A	3/4"	1-1/8"	2 (Retracted)	-1"	6-1/4"	12"
Short	Fabex 560	9-1/2"	2-1/2"	N/A	5/8"	15/16"	6	1-1/2"	11"	12"
	Lippert 0115	8-3/4"	2-1/2"	N/A	5/8"	15/16"	9	1-1/2"	10-1/8"	12-1/2"
	Venture	8"	1-1/2"	N/A	1/2"	3/4"	6	-4"	4"	12"