First, I should  probably preface this by acknowledging that while the term "stud" applies to many of you on the forum, YOU are not what I"m looking for. The stud I'm looking for is of the parts kind.

On the D15, the hitch assembly for the drawbar and factory 3 point hitch is held up by 3 cap screws (3/4" x 3") and one stud. Of the four holes used to hold the hitch assembly on, the stud hole is the front right, and the stud hole opens into the transmission case. Take out the stud and all the transmission oil dumps out on the ground.

We are on the hunt for just such a stud. The AGCO parts books shows it to be part number 70228028, and the same stud is found on the D14, D15 and D17 (both snap coupler and 3 point tractors). It is 3/4" diameter by an unknown length. Parts book only describes it as a stud, with no dimensions given. *

So looking for somebody who has one. If nothing else, it would be helpful if you could pull it from a parts tractor to measure it to tell us what length it is. It is probably 3 1/2" all the way up to 5". We don't know.

I checked with Cook's in Clinton, and despite this exact part being used on a lot of tractors, they don't have one in inventory. None of the parts tractors we have found has one either.

* One of my pet peeves is when looking for specifics, you get vague generalities instead. Like "just use a piece of string". Piece of string? Is it 12" or 36"? And what diameter and made of what? If you are supposed to use a 48" length of 1/4" braided poly rope, say so......don't tell me "piece of string". Or how far is it? Pretty far. Well how long will it take me to get there? Quite a while? How many miles, exactly? More than  you might think. Of if you are trying to duplicate a recipe, you get exact measurements for everything except some key ingredient......like sugar. For that, its "add sugar to taste". Does that mean 1/4 cup, more or less, or 2 cups, more or less, or how &*$*$^$*#$(* much!!!!! 

Stud?

or you could use a grade 8 bolt and cut the head off and cut it to the length you need and then thread the other end for the nut

i would,, since you have already pulled the bolt and the tranny is empty use a piece of wire with a bend on the end(slide it into the bolt hole turn it to hook it on the inside of the casting and then mark it pull iti out and measure) to see how thick the casting is,,,i wouldnt think you would want the stud sticking into the gear box any deeper than needed,,,mark it,,,the wire,,,and then add what you think you want for length for the nut and lock washer(part sticking out past the nut isnt to important) then cut to what ever length you need

i would be careful when you tighten it up,, unless there is a shoulder???( does the original style have a shoulder or a space between the threaded ends?? do you have at least a picture or diagram of the said stud??),,if you make one that would be easy to do so the part going into the tranny only goes in so far,,,when you tighten the nut it could run that stud into the tranny deeper,,if it doesnt have a shoulder,,,make sure you glue the threads up good with thread sealer or loc-tite,,,,i would think loc-tite would be best but i aint doin it,,,,clean the threads in the tranny casting really well with acetone or some other cleaner good,,,let it dry and put lots of sealer on both,,,the internal and external threads and screw then together and let it set,,,,get away from it for at least 24 hrs

if i can help ,,,,make a stud for you let me know,,,,i will need some dimensions,,,length,,diameter and threads per inch

just some thoughts and my .02

ocharry

ocharry:

Good suggestions and questions. As for sketches and all else, we don't know. Parts books are void of any detail and nobody seems to have ever laid in eye on one. Studs yes, exact dimensions of this stud so it can be duplicated, no. Frustrating.

Also, lacking this level of mechanical knowledge, I'm struggling to understand the difference in function between a cap screw (bolt) and stud. Why one vs. the other?

We took a cap screw that matches the other three out of the hole. It had worked loose, so was leaking oil and would not remain tight.

So how would a cap screw differ from a stud, provided you cleaned up the casting hole and used the same locking sealant on both?

Or in other words, why did the engineer who designed the thing use a stud vs. the same cap screw he used in the other 3 holes?

So when you are trying to decide on what to do.....

1. Find a stud no matter what? (and BTW, what grade is this stud?)

2. Best alternative is grade 8 threaded rod....meaning no shoulder?

3. Last alternative......grade 8 cap screw?

BTW, there are 8 similar studs holding the wheel castings on to the transmission case. 4 on each side. We have 8 of those on a parts tractor....but those studs are a different part number. So no idea if they are the same, as we don't know what the dimensions of the hitch assembly stud is. Which is why I'm trying hard to find the original correct one to measure. 

If they were the same, we have a pant load of those.

I just replaced the four on my D14 with thread rod cut to 4 1/2".  Clean out the holes with a tap and some brake cleaner and put some locktite on the stud.  I used a double nut to tighten them.  I recently took the 3 point adapter off and after a couple years, none had come loose.  I got my thread rod at Midstate Nut and Bolt.  It has a strange, to me, rating but it is hardened.  Just provide the size and tell them #8 and they'll know.

https://www.midstatesbolt.com/" rel="nofollow - https://www.midstatesbolt.com/

Yes I do! (on the housing)

Any other reference to pant load and studs should be in the singular form of stud (as in only one).....both for the hitch and actual pants. (except I don't have one for the hitch)

grade 8 for sure,,,it is the hitch,,draw bar

you could use threaded rod,,,but i would want some kind of stop on it so it only goes in so far,,,,mess up the threads,,,,put a spot of weld on it and grind it back smooth,,,, something to stop it from going farther in

you need to measure the casting thickness so you know how much thread you need so it doesnt go into the tranny to far

if you have studs from a parts tractor that are the right length on both ends,, even though they are different part no. they are more than likely the same grade and will work fine,,,i wouldnt be afraid to use them here

or cut a grade 8 bolt head off,,,thread the end going into the casting to the proper length and have a shoulder to stop it from going into the casting to far

first you need to know how long the casting side of the stud needs to be,,,,and then i would be looking at those studs from the donor tractor,,,,if they are the right size that what i would use,,, stud would be my first pick

my .02

ocharry

Trying to be helpful, here I called Brenda at Sandy Lake, gave here the part number and in about 15 seconds she said she can get one out of Tennessee for 3 bucks and freight. Could be a solution to your stud issue??

That may be the solution I'm looking for.

I"m not familiar with Brenda or Sandy Lake. Do you have a phone number?

Edited......of course you have a phone number. Correct question was if you could share the phone number?

Regards,

 Chris

Maybe in case of the tractors it was easier in assembly at the factory to have a stud to slide the part on then put nut on then install the cap screws.

Dusty 

An update.......shop where work is being done just happens to have a stripped down transmission casting off a D14, which we think is the same as for the D15. Part number of the stud is the same, at any rate.

So we pulled one of the the 8 studs holding the axle assembly on to test it in the stud hole for the draw bar / 3 point hitch assembly.

This is what the axle stud looks like and how it mounts in the casting:

So basic plan is to coat it with a sealant, then screw it into the casting hole until the threads on the stud run out, where it jams against casting. Flat spot with no threads bears the load placed on it by the assembly part being held up, then the 2nd threaded part that stands proud outside the assembly is fitted with nut and washer to pull part tight to the casting. Stud coated with sealant or locktite was not under any load when it went in, and jammed up like it is cannot turn like all thread would. And it really only needs to hold in place against the force of the nut turning against it.

This is the view from inside the casting......

Red circle shows where stud from draw hitch enters case. Stud coming in from axle is above it. They all stand a bit proud inside the casting so as to use all of the casting threads.

To be continued..........

Our guess was this stud needs to have about 1 1/2" of thread, a 1" flat spot in the middle, and an additional 1 1/2" threaded piece.....or 4" total. The one in the photo is only 3 inches coast to coast.

Owing to the recommendation of "stud" Chris on the forum, I did call Brenda and she  has an OEM stud on the way. So it looks like we will finally get our hands on the real deal stud to find out.

Stay tuned!

BTW, still wondering why the guy who designed the thing would use 3 cap screws that bottom out inside the casting (do not touch oil) and one stud that opens up into the casting into the transmission case where it can leak oil. Why not make all 4 of them the same?

And on the D17, at least early series, all four of the rear fasteners holding the hitch assembly up are studs. No cap screws on those. At least that is how the parts book shows it.

Good you have a stud on the way.

My guess is same as someone else mentioned. When installing the hitch this stud is used as a alignment feature and also when the hitch is up in place only a nut/washer combo is required to hold it while you go find the other bolts that you lost when you took it apart. Other than that no good reason that I see. Why it goes through into the case? Not sure? maybe that area of the casting is different?? Tapping engagement for a stud may have had to be deeper than a cap screw. Its not supposed to be the drain. Need to talk to the old Allis design department!

Ok went back and looked at the red circle picture. The casting has a depression in that area compared to the bump across from it, which is probably the threaded hole for a cap screw. If that's the case then the stud was never supposed to come out during removal of the hitch. It was to stay in place and act as a plug for the oil, but also have the function of a fastener. Time and much hard work changes everything!

BTW, I was curious how Brenda was able to find this OEM part since AGCO lists them as NA. She explained she works with one or more companies that go around and purchase all remaining parts inventory of implement dealers that close down. They then place them in their inventory. So a bit like Cooks in Clinton, MO, except many if not most of these remain OEM new parts, not used.

And for better or for worse, they do not up-charge them based on scarcity. One left in inventory or 100.....all the same price. Amazing.

Drain plug is in the lowest spot. The stud hole in the casting is about 2" above it. Transmission holds nearly 15 quarts and all but 1 or 2 of those dumped from the stud hole. The rest came out the drain plug.

BTW, in addition to the draw bar/hitch assembly stud, all 8 of the studs for the rear axles open into the transmission case and all are wet. Except they screw in from the side instead of from the bottom. Still, might pay to keep an eye out for leaks on those too.

ACinSC wrote: Modirt , can you please post the axle stud part number . My D 15 has 7 studs and 1 bolt . Of course the bolt's leaking . Thanks

Part number for the axle studs should be 70227525. That stud is about 3" in length.

Part number for hitch assembly, the one I've been looking for, is 70228028. Hasn't arrived yet, so we don't know what size it is.

BTW, before finding out I could get the OEM stud, I took a guess and ordered one from McMaster Carr. They called it a "setup stud". That one isn't going to work. Instead of a solid/smooth section in the middle, it has flat spots on it so you can turn it with a box end wrench. So no load bearing surface in the middle. In that, no better than all thread, even though it is a stud.

wfmurray wrote: Reading about stud.Have a well worn 1940 machinest handbook. It has some details on studs.Helped dad put a pto on a wc when about 10 years old and it came with studs.Install stud by double nuts and run stud in all the way so it tightens on inperfect thread.This keeps it from leaking and keep it intack when removing nuts. Glad you found some studs.WAy to go BRENDA!

We didn't have the manual, but after some deep thinking and discussion, came to the same conclusion on how to install it. Brilliant minds think alike? Plus a sealant of some kind or locktite to "lock it" in place (tightening against the smooth, threadless part in the middle may also lock it in place), but it needs some kind of sealant to keep the oil from seeping out through the threads, plus if the threads are wet with oil, they will work loose easier.

Working loose and falling out must be an issue as none of the tractors we have to look at have the stud. It's been missing in action everywhere we look.

Well crap......

OEM stud arrived today and if this is right, I've got it all wrong.

From top to bottom.....

Cap screw....a 3/4" x 3" bolt. This is the one that came out of the hole. Look close at 4 bottom threads and you will see those have been flattened out.

Next down (#2) is the stud from the axle. When I screwed this stud up into the hole on the empty D14 casting we have to play with, it ran out of stud thread before it ran out of casting thread, so was going to need to be at least 1 1/4" of thread, plus the nearly 1" of flat spot for the hitch assembly to ride on, plus enough remaining thread for lock washer and nut. I figured it would need to be at least 3 1/2" long, and maybe 4". The all thread we have in it to plug the hole temp is 4". #2 stud is 3" long.

So #3 down from the top (red box) is what I was sent as the OEM part#70228028. Either I have it all wrong or this is NOT that part. This thing does not have enough thread to cover all the casting threads, and no flat spot for the hitch assembly to ride on like the #2 axle. In short, I have serious doubts this is the right part.

#4 down from the top is the stud I ordered from McMaster Carr. It seems to me to be closer to being right than any of the others, but again, has the flat spots on the middle part that will bear no weight.

So back to the drawing board.

If anyone has a D14, D15 or D17 parts tractor with one of these studs still in it, I would dearly love to have you pull it out to see what it is really supposed to be.

Looks like a stud. 

Regards,

 Chris

Yes it is a stud.....question is if the stud they sent me an honest to goodness 70228028.....or is it something else. The stud itself has no markings on it. None of them do. Worse, there is no place we can find with any sort of description in the way of dimensions. It is only described as a "stud".

BTW, Brenda found two locations who had these in stock. One in TN, another in WI. Mine came from TN. I called her back and she is going to check with WI to have them measure the OEM studs they claim to have and see if it is identical to this one. If it is, we have some head scratching to do. In every way I look at it, it seems wrong to me. It is too short and has no load bearing flat spot in the middle. Basically no different than a piece of all thread that is too short to work.

And of course this all happens on a Friday, so good luck getting any kind of answer until next week.

 How thick is the plate and washer and nut stack up, that gets bolted on?

That 7022... should bottom out ok when double nutted and locktite/sealant applied.

Not sure which end goes in case? 

By design you only need 1.5 times thread sized for max engagement/ strength.

Also not sure about the grade of all these, the AGco one might be the toughest????

Regards,

 Chris

7022 Axle stud is 3/4 10.

OK, Brenda (gods gift to AC) called back this morning with two bits of news. WI checked their entire inventory and all are exactly the same. Plus, she had someone go out and check a parts tractor that is thought to have a factory installed stud and it is the same. So as near as we can tell, that 2 1/2" stud is the honest to goodness OEM stud.....which makes no sense whatsoever.

There is roughly 1 1/4" to 1 1/2" of thread in the transmission casting. So if you want to fill the entire hole with threads, you need that much. Or 1.5 x .75" = 1 1/8", but that wouldn't fill the threads. But even with that, the drawbar/hitch assembly still has about 3/4" to 1" of flat smooth surface that rides on the edge of the stud, and would still need enough thread left to mount a nut and washer protruding out beyond.

If you were to use the 2 1/2" OEM stud, it would offer little if any structural support to the hitch assembly acting as nothing more than a drain plug to fill the hole. Considering that all drawbar and 3 point loads are taken up in sheer and tension by just these 4 fasteners, giving up one of them to act as a cosmetic drain plug makes no sense. If this is right, it is no better than a simple piece of all thread, which offers minimal support to the drawbar assembly. The tips of the threads would quickly be rounded over and start doing nothing. That had already taken place on the existing cap screw.

Of all the options I have now, the 3" stud put in backwards to put the longest thread section in the casting to cover as many threads as possible, then let the hitch assembly ride on the smooth middle section, and hope you have enough threads left to attach a nut...is the best option.

Next best would be a cap screw like all the others, but it may take a shorter one with only a small area of smooth shoulder for the assembly to ride on. One with 1 1/2" of thread and about 1" smooth section below the head. 2 1/2" may be about right. That may not fill all the casting threads, but will get most of it. Will plug the hole and offer load bearing surface to boot. Now that I think about it, the existing 3" cap screw may have stopped going in when the smooth section of bolt hit the casting threads. Tightening up on that vs. the lock washer and bolt head drawing down tight. Maybe that is why it kept backing out?

Considering all of the tractors we have found that have no studs in them, it seems they were all replaced for some reason. Either they fell out, or were the wrong part for the job.

Machining up something from scratch is certainly an option, but considering the large number of tractors there are......all with the same issue, finding an off the shelf solution would seem to be the best alternative.

If an actual stud is to be used (vs putting another cap screw back in), the 3" stud from the axle housing looks like the best option so far. And again, the parts unit we have has 8 of them just sitting around doing nothing.

Below from McMaster Carr......I think this is the type you were thinking of. Problem being selection is limited, and none of the right size.

Best option still seems to be the Axle stud we already have.

Still hard to believe that with so many of these tractors out there, this issue has not popped up before with a known solution already devised.

If you have NOS, can you measure one and give the dimensions and possibly post a photo of it?

Curious if it is the same or different than the NOS stud we found before.

Unless it is different, we will be using the axle stud.

OK, now that I have had a chance to test the OEM stud on the parts casting, Brian's theory proved out. The two threads do not match. One is a tight fit, the other a loose fit. The same is also true of the axle stud.

However, as the axle stud came from the casting, the loose fit end was in the casting, yet it was not loose. I didn't take it out, but the guy who did had to use a pipe wrench on it and said it was moving the entire casting around to get it to free up. 

A 3/4" nut spins on easy on one end, and is very tight on the other.

So decision time. Tight or loose fit end into the casting? BTW, on the OEM stud, threads are 1 1/4" (that will cover all casting threads), or 1 1/8", with half of a thread in the casting left exposed. Balance of the 2 1/2" stud being the 1/8" transition in the middle.

And still think the better option remains to use the axle stud with load bearing flat spot on it to take the load of the drawbar/hitch assembly vs. letting any load ride on the tips of the threads.

Photos below......casting was laid on it's side to test fit things. Top stud is one of the axle studs, lower one is an axle stud in the hole.....loose fit in.

2nd photo shows the OEM stud in the hole. There would probably be enough exposed thread to start a nut, but again, hitch assembly load would be riding on the tips of the threads.

The mystery of the OEM stud is starting to clear up. Turns out I screwed up. When searching for the part number, the stud I found was for the snap coupler assembly. It was the same for several models.

While searching for parts for the factory 3 point, I again noticed the mounting stud, looked, and lo and behold different part number. The correct part number for the factory 3 point is 70236541. Called Brenda and she found one of these too. And here is what the correct OEM looks like:

This one is about 3/8" longer than the axle stud, and the main difference is the width of the flat spot in the middle, which corresponds to the depth of the casting that mounts to it, plus threads on both ends are a bit longer.

I have not checked to see if the threads differ, but suspect they do.

Both the axle stud and this stud have an R etched on one end. My guess is that is the end that gets inserted. Don't know what R means, perhaps someone else does? The other end is smooth.

Clip Paste Flip, just another way to look at it.

When used as wheel studs, R stands for right hand thread. 

Looks like the correct replacement item was found. Good job!