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 H.

full restoration in progress
1952 M38 MC60228

[Pierre]

_________________
Pierre H.

full restoration in progress
1952 M38 MC60228

[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!
_________________
Ron D.
1951 M38 Unknown Serial Number
1951 M100 Dunbar Kapple 01169903 dod 5-51

“The only good sports car that America ever made was the Jeep."
--- Enzo Ferrari

[BobW]

I think M-38 Spring Pivot Brackets have a different width than Civilian Jeep Brackets.
_________________
Bob W. Monticello, NY. 1952 CJ3A, 1952 M38, 1950 CJV-35/U

[Pierre]

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

Thanks
_________________
Pierre H.

full restoration in progress
1952 M38 MC60228

[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).
_________________
Ron D.
1951 M38 Unknown Serial Number
1951 M100 Dunbar Kapple 01169903 dod 5-51

“The only good sports car that America ever made was the Jeep."
--- Enzo Ferrari

[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:

[Pierre]

[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
_________________
Pierre H.

full restoration in progress
1952 M38 MC60228

[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]

[Pierre]