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Kind of an odd-ball question, but can anybody give dimensions of leaf spring U-bolts for the left front M38 or MBT and M416 trailers?? Mine on the M100 are shot and need to be replaced. They measure 2-1/4 wide by 6 inches tall (inside dims), flat top, with 7/16-20NF threads for the long hex nuts. They sit on 10-leaf springs. I believe the whole set-up is original Dunbar-Kapple.

The M100 TM's don't give dimensions for the U-bolts, and neither does the M38 TM's so I can't really tell what's correct or not. The U-bolts on the LF of my M38 seems long to me, about 1-1/2 inches exposed below the nuts. The M100 part number is 7328295. Research leads me to believe they may be the same U-bolt as the left front on the M38 and possibly the same on the MBT and M416 trailers. But each has its own different part number (WO-A575, WO-642987) so I can't tell for certain.

Anyway, I thought I'd ask here for some guidance/advice before I call the suppliers and pester them with questions about various leaf spring U-bolt dimensions so I can get the correct size U-Bolts the 1st time. Nobody shows stock on the M100 part number 7328295. I'd rather not have to get them long and have to cut them shorter if I can help it.

Thanks!

The U-bolts on the front of my M38 are flat-top and measure about 3 1/4 inches from top and 3 1/4 wide with about 1/4 inch of threads exposed.
The U-bolts on my M100 are round-top and measure about 3 1/2 from the top and about 3 1/4 wide and also have about 1/4 inch of threads exposed.

Hi Kendall, thanks for the measuring! It looks like your M38 and M100 U-bolts have about the same width (about 3-1/4 wide outside dim). With the U-bolt being 7/16, my stubby pencil says that's about 2-3/8 inside diameter. I measured my M100 axle at 2-1/4 diameter, and my M38 axle at 2-5/16.

You prompted me to see if my old wore out M100 U-bolts would slip over my M38 front axle tube and no, not without some serious forcing (didn't do that). Should've tried that sooner. I think I was wrong with my original post to say that I thought maybe the M38 front axle U-bolts were the same as the M100. I no longer believe they are.

Looks like I need a want ad for M100 U-bolts. Never seen any advertised or NOS. Does anybody make them?

Thanks again!

Firts look up the parts number for the U bolt. If you go to the TM 9-2330-201-14 (M100 IPL) and round up the ORD part # 7328295 and the FSN 5306-732-8295 and google the ORD # the first hit is:
https://aerobasegroup.com/part-number/7 ... 0-732-8295

7328295
U Bolt; Fine Thread - 2A

7328295
Description: 2a Unf Thread: 7/16-20, Thread Length: 1-1/2"

Specifications
Distance From Inside Center Of Bend To Bolt End: 6.140 inches AAWV
Material: Steel comp 1335 or steel comp 1340 or steel comp 8630 or steel comp 8635 or steel comp 4130 MATT
Minimum Yield Strength: 140000 pounds per square inch CQHQ
Thread Diameter: 0.438 inches AHYM
Inside Distance Between Shanks: 2.281 inches AAWW
Style: Round bend STYL
Surface Treatment: Phosphate SFTT
Thread Class: 2a AAJD
Thread Direction: Right-hand AAJF
Thread Length: 1.500 inches minimum AASA
Thread Quantity Per Inch: 20 CMLP
Thread Series: Unf THSD
Federal Supply Class (FSC): Bolts
National Stock Number (NSN): 5306-00-732-8295

Thanks Wes! Awesome!

It never occurred to me that the part number is also the last 7 digits of the FSN. And then I looked up the part number 7328295 and forgot to pay attention that G747-7328295 is the complete part number, and G747 should've told me these U-bolts are unique to the M100 only or they might have had a G503, G529, or even a G740 prefix and part number. I'm learning.

I'll make some phone calls to see if I can get some made up.

It never occurred to me that the part number is also the last 7 digits of the FSN.

Don't always bank on that. You only see that normally on the very early FSN's that started being used in the early 50's.

Found an outfit in Ohio that makes custom U-bolts and has 2-1/4 x 6 threaded 7/16-20NF in stock. They come with the extra thick washers and long nuts. Ordered 2 pair, price was reasonable. Will report when I get them.

DSUBAN.com! $9.88 each, delivered. Ordered Wednesday 2/22 and they were in my mailbox on Friday 2/24. Although the website allowed ordering 6-inch length, the way they make them came out at 7-inch, so I'll have to trim them an inch. The 2-1/4 inch width is right on.