Parts description needed

[cranetruck]

I need to replace 8ea O-rings on the 757, they are about 3 inches in dia and seem to have been flattened from use after 38 years.
NAPA measured one of them and came back with a "discontinued"....
I need the exact spec on them to go any further, so if someone has access to the right data base, please chime in. The NSN is 5330-00-050-2191, alternate part number is 10945228.
The description: O-ring, brake drum, outer.

TIA

 

[DDoyle]

Bjorn,
No help here on the NSN data - BUT - there are a number of specialty rubber supply companies (I learned this in previous industries - if you need a name, PM me and I'll try to come up with one for you).

Since you do in fact own your own business - dial one up, give them the measurements you got from NAPA, and tell them that you are an OEM and need this ring for the new widget you are developing.

You'll have to buy a lot of them, but they will be obscenely cheap.

HTH,
David Doyle

 

[cranetruck]

Thanks, I'll keep that in mind.

 

[Gamagoat1]

Not that this will help but here's some parts for 5 tons. I'd love to go see this one.
Ebay Item number: 230167172207

 

[papercu]

parts

According to the NSN last ones the military bought was back in 1980/08 contract number DAAE0780ME728 and bought 950 at 0.69 ea from MIL-CRAFT MF, 1282 W Arkansas Ln, Arlington, TX 76013-6235 phone 817-274-1385
Cross-Sectional height 0.210 inches nominal. made of rubber synthetic, Good luck, Wayne

 

[mangus580]

RE: parts

Bjorn, do your best to scare up the real dimensions... and I will see what we have at work.

 

[cranetruck]

Thanks for the offer Mike!

Measuring it, I come up with:

OD=3.400
ID=2.950
Cross sectional height=0.186
Cross sectional width=0.225

Perhaps it was never circular in cross section, but if that's all that's easily available, that will have to do for the time being.
The O-rings help seal the brake drums.

Thanks Wayne for your input, every little bit helps..

 

[mangus580]

If you dont hear from me by mid-day, remind me

 

[cranetruck]

 

[DDoyle]

Is it truly an o-ring? - from the pic it looks like a square-cut ring.

Regards,
David

 

[73m819]

take the o-ring to cat, thay have both the square and round stiles in almost any size that you could ever want, years ago i needed some special o-rings for a old autocar that i had, i found a industrial o-ring suppler in the phone book, gave them the old one, made two up on the spot, also another thought, you can buy a o-ring kit that comes with the o-ring material and special glue so you can make your own 0-rings, thay wook as good oems

 

[houdel]

A real off the wall suggestion here - If this is a square cut ring and not a true O ring - how about an oil filter cannister base gasket? Baldwin makes quite a few different sized gaskets, most of which are sold as individual parts, maybe you could get lucky and find one close enough to use. If you know how or if you know someone who knows how to search the Baldwin data base you might be able to find something which fits your needs. If you need help in the search I can go back through the old spin on filter for the Deuce thread, there was on person there who seemed to be very knowledgeable in Baldwin parts, although I suppose anyone else who sells cannister filters probably also has the same or similar gaskets.

 

[devilman96]

Bjorn,

Should be round about on this page if the link works correctly.

http://www1.mscdirect.com/CGI/NNPDF...649412&PMITEM=80189921&PMCTLG=00&PMT4TP=*LTIP

 

[cranetruck]

Thanks again for the suggestions, a big part of working on these vehicles is to get close to the originial on this kind of detail, since the design goals are not often exactly known.
It now looks like the O-rings are in fact supposed to be flat on the contact surfaces, just down a little from the original dimension (according to Wayne's number). I'll measure a few more to make sure.
Closeup shows surface pitting.

 

[JDToumanian]

That looks like it's flattened from age... I'll bet it was a normal round o-ring.

 

[cranetruck]

See...that's why the original spec sheet would be nice.

 

[DDoyle]

Bjorn,
I don't think it is a true o-ring because it is FSC class 5330 - packing and gasket material. O-rings are class 5331.

Bet if you contact the last known supplier using the info Wayne provided above you could get the specs - or maybe even the rings.

Wayne provided a contract number - specs for contract numbers can be found on the Rock Island Arsenal website - but I don't remember how far back they go.

Wayne, do you have the MS number? - I may be able to do something with that.

Regards,
David