Throttle Stop Shaft O-ring Size

[Wildchild467]

Does anybody know the correct size o-ring for the throttle stop shaft on the injection pump? I was told it was a "-013" but that is not the correct one. On my other deuce, I bought the injection pump gasket kit and used the o-ring supplied and it worked like a charm. this "-013" is too thick in diameter. The diameter of the "-013" is 1/16" and it needs to be smaller. I have searched high and low and I cant seem to find the right o-ring other than buying the entire kit. It's got me bummed out tonight because I cant fix it the correct way. When the o-ring is too big like the one in it now, it makes the throttle sticky (not in a dangerous way... just makes the engine surge), so its a pain to drive. Thanks for everybodys help.

 

[doghead]

Can you get the nsn for the oring from the kit?

 

[doghead]

I think I found the fsn for it in TM 9-2910-226-34.


5330-310-6659

Looking for more info...

 

[doghead]

Also in the tm, is the Ambac part number, GA76195.

I would confirm these numbers and call Ambac (American Bosch).

 

[Wildchild467]

Thank you very much for your research Doghead, I really appreicate it. I will look back through that TM and see where I missed it. I don't recall a list of part numbers in the kit I bought, only sealed packs of gaskets and o-rings. I have gotten other military kits such as the air activated brake light switch kit for my Deuce that had part numbers of all the items inside (which was nice to have).

When I installed the o-ring (the correct o-ring from the injection pump gasket kit) on the stop shaft on my M109A3, the o-ring had to be somewhat stretched to be put on the shaft. This seemed a little odd to me because I would have thought they would have just slid over a little easier. When it is stretched I would think that would reduce the thickness of the o-ring some.

74M35A2 brought up a good point to me the other day. If it is a German made pump, wouldn't they use metric o-rings and not SAE?

I copied this out of the TM and the part I am looking for is part "K" which is listed as a "Preformed Packing". I will do more research and make a couple calls today and see if I can find more information.

 

[Wildchild467]

Jackpot!.... kind of. I found this information about the size of the o-ring. Now I just have to locate the correct part number and supplier for the o-ring.

The NSN of the o-ring is 2910-292-1464 and the MFR# 10914594

 

[doghead]

When you posted "throttle stop shaft", I was guessing the "throttle arm shaft", not the shut off shaft.

The part number I posted is for the throttle arm shaft.

The number cross referencing is near the back of the tm(just before the index).

 

[doghead]

Look at figure B-2, item 11. Is that it? If so, that's 2910-292-1464.

 

[doghead]

Whoops, I read post #6 and went back to the TM, in search of the info and after posting again, I realized you had posted an update.

That's what I get for posting before reading all the posts... Hehehehe...

 

[doghead]

http://www.nsnlocator.com/rfq/5331-00-292-1464.html

 

[Wildchild467]

So the magic question is: What o-ring equates to it? -012? A -012 I would have to stretch a little bit to get it on, similar how the o-ring was from an original injection pump gasket kit I used before.

 

[Warthog]

From DHs specs and this o-ring chart, it does look like a 012.

http://www.allorings.com/size_cross_reference_framed.htm

 

[peashooter]

Jackpot!.... kind of. I found this information about the size of the o-ring. Now I just have to locate the correct part number and supplier for the o-ring.

The NSN of the o-ring is 2910-292-1464 and the MFR# 10914594

View attachment 511143

According to Mcmaster.com this would be a -012 size o-ring. They have 3 different Mil-Spec Buna-N orings listed, part numbers:
http://www.mcmaster.com/#4198T507
http://www.mcmaster.com/#4464T507
http://www.mcmaster.com/#4679T507

 

[Wildchild467]

I agree, it looks like -012 to me also. The o-ring I got on my lunch break is a -012 and is only rubber, not Viton or Buna N. I will see how it fits and go from there. My only concern is that with me using WMO and sometimes 10%-15% gasoline in the system sometimes, I don't know how it will effect it. I am going to try to locate a Viton o-ring in the mean time. Is Viton more stiff than regular rubber? Since I will have to stretch it a little bit to put it on the shaft, I didn't know how Viton likes that. Rubber is pretty forgiving.

 

[peashooter]

Is Viton more stiff than regular rubber? Since I will have to stretch it a little bit to put it on the shaft, I didn't know how Viton likes that. Rubber is pretty forgiving.

The Viton -012 orings from McMaster have a durometer (hardness) of A75, the mil spec Buna N orings from McMaster have A65 and A70 depending on which one you look at. So it appears that Viton is a little harder than a standard O-ring but not by much.

Viton is better or equal to Buna-N in every category other than abrasion, and compatibility with water (it still gets "FAIR" ratings, just not "GOOD" in those areas)

 

[jbayer]

Aircraft grade fuel resistent o-ring.
http://www.amazon.com/Military-O-Ring-MS29513-012-Nitrile-Pack/dp/B000R9MVN8
Pricey shipping here, but there are other places that have these in stock.

 

[brianp454]

Nitrile is Buna-N, which is the o-rings they have on the shelf at the local HW store for plumbing at about 10 cents. Calling it "Military" or "Tactical" does not make it "better." If you look up a chemical compatibility chart for elastomers you'll find that Viton (my top choice for many demanding applications) or PTFE are likely chemically resistant "better" materials considering the wide range of "fuels" people use in these trucks. If you poke around locally, you might have an o-ring or seal outfit that sells to local industrial places. Online with McMaster or other industrial supply places are easy solutions if you can't find them locally.

The -012 seems to be a very close fit, yet the cross-section is a bit over what the NSN info lists as the max. Likely not an issue though. It looks like the original version was Buna-N, so I would expect Viton to last much longer due to it's improved chemical compatibility.

If you want to learn about o-rings and seals, the Parker O-Ring handbook as lots of great info, including SAE and metric standard sizes. Shore A 70-75 hardness is the most common. There's also great design info for static and dynamic seals.

https://www.parker.com/literature/ORD 5700 Parker_O-Ring_Handbook.pdf

Aircraft grade fuel resistent o-ring.
http://www.amazon.com/Military-O-Ring-MS29513-012-Nitrile-Pack/dp/B000R9MVN8
Pricey shipping here, but there are other places that have these in stock.

 

[Wildchild467]

Success! The -012 O-ring worked! I will write a longer post about my findings later tonight. Thank you to all who helped me out! I'm going for a test drive now!

 

[brianp454]

I look forward it it! Please include pics. I have a couple little leaks in or around the IP and assume the o-rings haven't been replaced since the truck was rebuild in 93. I would like to get in and pro-actively replace the o-rings and see if that also helps with the slow leaks.

Success! The -012 O-ring worked! I will write a longer post about my findings later tonight. Thank you to all who helped me out! I'm going for a test drive now!

 

[jbayer]

Nitrile is Buna-N, which is the o-rings they have on the shelf at the local HW store for plumbing at about 10 cents. Calling it "Military" or "Tactical" does not make it "better." If you look up a chemical compatibility chart for elastomers you'll find that Viton (my top choice for many demanding applications) or PTFE are likely chemically resistant "better" materials considering the wide range of "fuels" people use in these trucks. If you poke around locally, you might have an o-ring or seal outfit that sells to local industrial places. Online with McMaster or other industrial supply places are easy solutions if you can't find them locally.

The -012 seems to be a very close fit, yet the cross-section is a bit over what the NSN info lists as the max. Likely not an issue though. It looks like the original version was Buna-N, so I would expect Viton to last much longer due to it's improved chemical compatibility.

If you want to learn about o-rings and seals, the Parker O-Ring handbook as lots of great info, including SAE and metric standard sizes. Shore A 70-75 hardness is the most common. There's also great design info for static and dynamic seals.

https://www.parker.com/literature/ORD 5700 Parker_O-Ring_Handbook.pdf

Well that' very good information, but, just so you, I do know a little about Mil #'s, currently still working (29 years, 1 month, 22 days)for one of the top three defense contractors where we build one the carrier based A/C from the ground up

Hint

Mil Spec O-Rings[h=1]MS29513, superseded by AS29513[/h]

Printable Page

(MS stands for MILITARY Standard, and no JO-SCHMO can just call their part "Military" as you put it))

[h=1][/h]"Packing Preformed O'Ring fabricated from MIL-P-5315P 70 durometer nitrile rubber used in aircraft fuel systems with jet engines (-65 to 200F) Hydrocarbon and fuel resistant." Quoted off the MIL SPEC