Leaf spring eye pivot bushing

[Pierre]

Hi everyone,



While restoring suspension components on my 52 M38, I've noticed the pivot eye bushings (rubber sandwiched between two metal tubes) I've ordered from multiple vendors are not quite the same length as the originals that I took out.

Originals have outer tube length at 1,815" and inner tube at 2,050"

From vendors both tubes are 1,815"

Which bushing is right or do I have the wrong brackets riveted to my frame which have about 2" between the ears?

[Pierre]

[RonD2]

Hi Pierre,
Paragraph 191 on page 181-182 of TM9-1804B (Power Train, Body, and Frame) only gives diameter and Paragraph 138 on page 151 says nothing about length having a wear limit.

Maybe this means length isn't critical? --- meaning if it fits, it's good?

I did a search on "pivot eye bushing" and didn't get anything informative concerning length.

Sorry, not much help.
Good luck!

[BobW]

I think M-38 Spring Pivot Brackets have a different width than Civilian Jeep Brackets.

[Pierre]

Can someone please measure the inside gap of the bracket on their M38

Thanks

[RonD2]

I measure 2 inches inside (machinist ruler not a micrometer).

The ORD9 pages 282-283 list pivot eye bushing as BEARING, Silent Block, WO-801624, ORD G740-7697597.

Both AJP and MWM list WO-801624 on their web site stores ($7 each).

[wesk]

Hello Pierre,

Generally the best way to determine part correct sizes is to have the factory blueprint for that part. Since it has been years since the Willys/Kaiser facility sold off it's assets, There is only a handful of archive hunters that escaped with thousands of factory drawings and production paperwork. However they tended to concentrate on their personal area of interest. Some for WWII production, some early postwar civvy production and some 1950-71 military production. We do have one member of this website who left Toledo with a very large percentage of the 1950-1971 military drawings. He has worked with Ryan Miller and myself on many occasions to help with high demand requests for specific drawings. Ryan's M38 build manual touches on the springs and frame brackets but lacks the measurements.

The next best source of dimensional info is with the FSN and NSN files. During and after WWII the Army supply system relied not on manufacturer's part numbers but instead on a military set of stock numbers common to all service branches and NATO member countries. These were Ordnance Part Number and Ordnance Stock numbers. They were usually 6 to 10 digits. If you review your M38's ORD 9 SNL G-740 parts manual you'll see these various numbers. Let's walk thru these numbers using this bearing as an example.

Page 283 of the ORD 9 SNL G-740 Section 1601.3 the first part is this bearing, silent block (rear spring). It shows there are 2 each used on the rear springs. Now the first number we should review is it's from the factory, manufacturer's part number which is the number preceded by WO- which ID's the number as a Willys Overland part number. The actual WO Part number is: 801624. This is the number you need to locate this bearing in it's factory blueprint. Just to the right is the Ordnance Part Number 7697597. This number ID's the part in the military supply system. Now all the way to the left column is the Ordnance Stock Number. This number was used for tracking common parts in the Army supply system. The G740 prefix ID's the part as an original M38 part (G740 = M38) so this means the part was introduced to the Army Supply system initially as an M38 part. Finally we look at the Federal Stock Number column or as it is more commonly known FSN. This became the new primary management number for a part in the military supply system around 1948-1950. We were still using this primary number for procuring parts throughout my Army and Air Force career from 1966 thru 1989. Then as the equipment and parts reserves of the combined services of all NATO countries became very huge (Grandiose) they needed a couple more digits to manage this vast stockpile of parts and that was the beginning of the National Stock Number or Nato Stock Number also usually referred to as NSN. This number has been the primary supply management number for 33+ years now.

So if you wish to know more about a part then shop google with the part's FSN or NSN and you will be amazed at the massive amounts of information in that system. You probably are wondering how the FSN's became NSN's? Well the military supply system simply added two digits. Thus the FSN 3120-769-7597 becomes an NSN by looking like this. 3120-00-769-7597.

Here's the Google explanation of the breakdown of the NSN:

Every NSN consists of 13 digits; a four-digit NATO supply classification group code, followed by a nine-digit national item identification number (NIIN). The NATO supply classification group is comprised of the NATO Supply Group (the first two digits) and the NATO Supply Class (the second two digits).

When you research using the FSN and or the NSN here's an example of the results: https://www.wbparts.com/rfq/3120-00-769-7597.html

NSN 3120-00-769-7597 10102, 7697597, 801624
Home Part Directories FSG 31 3120 3120-00-769-7597
Product Details | SLEEVE BEARING
3120-00-769-7597 A tubular shaped item with or without flange(s) designed to reduce friction and carry a kinetic load on the surface(s) parallel to the axis of the bore. It must have a visible or detectable means of lubrication or be self-lubricated. The over all length must exceed 25 percent of the outside diameter or the shortest distance between peripheral flats of the body, except for straight tubular (without flange or shoulder) items having a bearing surface(s) parallel to the axis of the bore only. Includes items which are divided into two or more segments which include 180 degrees (3.141 radians) or less of the bearing periphery. See also BUSHING, SLEEVE; SPACER, SLEEVE; and WASHER (as modified). Excludes PIN, HOLLOW.

Part Alternates: 10102, 7697597, 801624, 3120-00-769-7597, 00-769-7597, 3120007697597, 007697597

Bearings | Bearings, Plain, Unmounted

Supply Group (FSG) NSN Assign. NIIN Item Name Code (INC)
31 01 JAN 1962 00-769-7597 13205 ( BEARING, SLEEVE )
Drawings & Photos | NSN 3120-00-769-7597


Cross Reference | NSN 3120-00-769-7597
Part Number Cage Code Manufacturer
10102 27387 TENNECO INC. DBA TENNECO
7697597 19207 U S ARMY TANK AUTOMOTIVE COMMAND AMSTA-IM-MM
801624 34623 AM GENERAL, LLC
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NSNs for Compare ( up to 4 ): Add 3120-00-769-7597
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Related Products | NSN 3120-00-769-7597
Part Number
Part Number
Part Number
Part Number
Part Number

3120-00-769-7785, 3120-00-769-7880, 3120-00-769-8069, 3120-00-769-8352, 3120-00-769-9382

Technical Data | NSN 3120-00-769-7597
Characteristic Specifications
MATERIAL STEEL INNER LAYER RUBBER INTERMEDIATE LAYER STEEL OUTSIDE DIAMETER SURFACE OF FLANGE
STYLE DESIGNATOR 21C SOLID
OVERALL LENGTH 1.9900 INCHES MINIMUM AND 2.0100 INCHES MAXIMUM
BODY OUTSIDE DIAMETER 0.7800 INCHES MINIMUM AND 0.7850 INCHES MAXIMUM
BODY INSIDE DIAMETER 0.4470 INCHES MINIMUM AND 0.4530 INCHES MAXIMUM
FLANGE OUTSIDE DIAMETER 0.8780 INCHES MINIMUM AND 0.8830 INCHES MAXIMUM
FLANGE WIDTH 1.7400 INCHES MINIMUM AND 1.7600 INCHES MAXIMUM
END TO FLANGE DISTANCE 0.0940 INCHES MINIMUM AND 0.1560 INCHES MAXIMUM
LEFT END BODY DIAMETER ANY ACCEPTABLE
RIGHT END BODY DIAMETER ANY ACCEPTABLE
CORNER SHAPE SQUARE OUTSIDE LEFT CORNER SQUARE OUTSIDE RIGHT CORNER SQUARE INSIDE RIGHT CORNER SQUARE INSIDE LEFT CORNER SQUARE LEFT FLANGE OUTSIDE RIGHT CORNER SQUARE LEFT FLANGE BODY CORNER SQUARE RIGHT FLANGE OUTSIDE LEFT CORNER SQUARE RIGHT FLANGE BODY CORNER
MANUFACTURERS CODE 19207
DESIGN CONTROL REFERENCE 7697597
Restrictions/Controls & Freight Information | NSN 3120-00-769-7597
Restictions
Freight
Category Code Description
Hazardous Material Indicator Code N There is no data in the HMIS and the NSN is in an FSC not generally suspected of containing hazardous materials
Demilitarization Code: A Non-Munitions List Item/ Non-Strategic List Item - Demilitarization not required.
Precious Metals Indicator Code: A Item does not contain precious metal
Criticality Code: X The item does not have a nuclear hardened feature or any other critical feature such as tolerance, fit restriction or application.
Automatic Data Processing Equipment: 0 Represents items with no ADP components. NOTE: Codes 1 through 6 are only to be used when the item is Automatic Data Processing Equipment (ADPE) in its entirety and is limited to the type meeting only one of the definitions for codes 1 through 6. (See code 9)

Here's another: https://nationalstocknumber.org/nsn/3120-00-769-7597

Sleeve Bearing NSN 3120-00-769-7597
Item Description
A tubular shaped item with or without flange(s) designed to reduce friction and carry a kinetic load on the surface(s) parallel to the axis of the bore. it must have a visible or detectable means of lubrication or be self-lubricated. the over all length must exceed 25 percent of the outside diameter or the shortest distance between peripheral flats of the body, except for straight tubular (without flange or shoulder) items having a bearing surface(s) parallel to the axis of the bore only. includes items which are divided into two or more segments which include 180 degrees (3.141 radians) or less of the bearing periphery. see also bushing, sleeve; spacer, sleeve; and washer (as modified). excludes pin, hollow.

NSN 3120-00-769-7597
NSN: 3120-00-769-7597
Provided with every order
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Related NSN
3120-00-770-1750 Sleeve Bearing
3120-00-770-1761 Thrust Washer Bearing
3120-00-770-2480 Thrust Washer Bearing
3120-00-770-2536 Sleeve Bearing
3120-00-770-2593 Sleeve Bearing
3120-00-770-2770 Sleeve Bearing
3120-00-770-2941 Sleeve Bearing
3120-00-770-4113 Sleeve Bearing
3120-00-770-4161 Sleeve Bearing
3120-00-770-4727 Sleeve Bearing
3120-00-770-5096 Sleeve Bearing
3120-00-770-5189 Sleeve Bushing
3120-00-770-5280 Linear-rotary Motion Roller
3120-00-770-5747 Sleeve Bearing
3120-00-770-6060 Sleeve Bearing
3120-00-770-6974 Sleeve Bearing
Features and Characteristics
Overall LengthBetween 1.9900 inches and 2.0100 inchesBody Outside DiameterBetween 0.7800 inches and 0.7850 inchesBody Inside DiameterBetween 0.4470 inches and 0.4530 inchesFlange Outside DiameterBetween 0.8780 inches and 0.8830 inchesFlange WidthBetween 1.7400 inches and 1.7600 inchesEnd To Flange DistanceBetween 0.0940 inches and 0.1560 inchesCorner ShapeSquare right flange outside left cornerLeft End Body DiameterAny acceptableRight End Body DiameterAny acceptableMaterialSteel outside diameter surface of flangeStyle DesignatorSolid, external flangeFSC3120 Unmounted Plain BearingsNIIN007697597NSN3120007697597
Manufacturer Part Numbers
Part numbers registered to this national stock number.
Part NumberCageStatusMSDS769759719207A1010227387A80162434623A
Foreign Trade & Schedule B
What is a Schedule B number? Find more information at help.cbp.gov
Schedule B Number: 8482997090
NAICS: 332991
SITC: 74699
Description: Parts, nesoi, for roller bearings or for combined ball/roller bearings, nesoi
End Use (Code 21180):
Industrial machines, other
Q & A
Frequently asked questions for NSN 3120-00-769-7597
What are the manufacturers of nsn 3120007697597?
U S Army Tank Automotive Command (19207)
Tenneco Inc. (27387)
Am General Llc (34623)
Does this nsn 3120007697597 have a shelf life?
No. This NSN does not have an applicable shelf life.
What is the formal definition of nsn 3120007697597
A tubular shaped item with or without flange(s) designed to reduce friction and carry a kinetic load on the surface(s) parallel to the axis of the bore. it must have a visible or detectable means of lubrication or be self-lubricated. the over all length must exceed 25 percent of the outside diameter or the shortest distance between peripheral flats of the body, except for straight tubular (without flange or shoulder) items having a bearing surface(s) parallel to the axis of the bore only. includes items which are divided into two or more segments which include 180 degrees (3.141 radians) or less of the bearing periphery. see also bushing, sleeve; spacer, sleeve; and washer (as modified). excludes pin, hollow.
Does nsn 3120007697597 contain any precious metals?
No precious metal content.
Does nsn 3120007697597 contain any hazardous materials?
No MSDS. No hazardous material.
What is the ESD classification of nsn 3120007697597?
No known electrostatic discharge.
Identification Group
Item Identification Guide (IIG) and Item Name Code (INC)
INCFIIGApp. KeyCond. CodeStatus13205A045A0D1A

[Pierre]

Both AJP and MWM list WO-801624 on their web site stores ($7 each).

Thanks for the search Ron, unfortunately I have those bushings from both vendors but the ends are flush at 1,8" therefore come up too short for the 2" brackets. It's misleading that vendors use same part numbers as the military but actually are NOT the same part...Obviously in this case parts sold are not NOS for this particular application.

I have 2" brackets on my frame as well, thanks for verifying that for me.

I talked to a suspension shop specialist in my area and he tells me that all silent block bushings should be the same length as the gap in the bracket.
wether they're flush or with the longer inner tube. Any gap between the bushing and the bracket can result in unstable driving as suspension leaves have room to move laterally.

[Pierre]

Thank you Wes for the wealth of information. Very interesting history and explanation of NSN numbers. Thank you for that.

I am aware of the different part numbers in the SNL manuals, TM-9's, etc...
I'm constantly looking in those manuals for additional info but unfortunately apart from actual procurement numbers they sometimes come up short in technical data.

I do have Ryan's book which is very useful at times but in this case not so much. As we gather additional missing data info on the M38, perhaps an updated edition will be in the works

As for the actual original part itself I was blown away with results you got from Google. I never seem to get those answers from that search engine but I'll try again.
wbparts.com has the bushings with the exact same specs (ex: inner tube at 1,99")and description as my original within 5 thousands which in this application won't matter.

If anybody else can confirm the 2" bracket gap on their unmolested M38 frame
that would be appreciated.

Hopefully this will help someone else one day while restoring their M38

Cheers

[1948willyman]

My 1952 M-38 also measures 2 inches according to metal 12 inch stick
Sure, mine is unmolested model best I can tell.

[RonD2]

I talked to a suspension shop specialist in my area and he tells me that all silent block bushings should be the same length as the gap in the bracket.....Any gap between the bushing and the bracket can result in unstable driving as suspension leaves have room to move laterally.

Any chance the suspension shop specialist can locate the correct size part or suggest a solution for you?
Maybe he can turn down a slightly longer one for you to fit?
Just spit-balling......maybe use a couple of grade 8 hardened washers to fill the gap?

I'm disappointed to learn that AJP and MWM have the wrong parts, especially if they're NOS with factory labels.

[Pierre]

Any chance the suspension shop specialist can locate the correct size part or suggest a solution for you?
Maybe he can turn down a slightly longer one for you to fit?
Just spit-balling......maybe use a couple of grade 8 hardened washers to fill the gap?

Lol
Interestingly we had a long discussion about it couple weeks ago as he was beefing up my rear suspension on my Silverado pick up with Timbrens.
He's been trying to locate the bushings with his distributor that match the specs I gave him but so far no luck. The closest were the same as I've been getting from our usual parts vendors. He did however suggest using washers to fill the gap but warned me that the washers will also put pressure on outer tubing and the rubber between the tubes won't fonction as intended under stress and the rubber section will eventually break.
Only a temporary solution. As he explains it in this application the longer inner tube is the only one that has contact with the bracket inner wall. As suspension flexes the rubber and outer tube takes the pressure and ever so lightly twist.