M38 - Nothing at all to do with M151s

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Re: M38 - Nothing at all to do with M151s

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Re: M38 - Nothing at all to do with M151s

Postby m3a1 » April 22nd, 2018, 8:40 pm

Keeping these shims located where they came from throughout the overhaul of this steering gearbox is important if everything is expected to go back just the way it came off. Believe it or not, the purpose of these shims is to perfectly align the steering gear box to the long axis of the frame which, in turn, optimizes the linear movement of the pitman arm. Hard to believe, eh? These people were serious about their product.

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I just went at this with the drill and a cupped wire brush and knocked off most of the junk before getting into the internals. At the outside and bottom of the gearbox (that part that is closest to the ground when it is bolted to the frame) is the end of the oil tube that serves to allow the horn circuit wire to pass through the gearbox. This oil tube is actually rather frail and it attaches by being peened over on the cup at the bottom of the gearbox so, go easy when you're cleaning up that area and don't be too aggressive with whatever tool you might be using.

Speaking of clean-up. The oil tube is just about .22 cal so if you have a bore brush, it will do a very nice job of cleaning up the interior of the tube. Just be sure to support it well while you're cleaning it out.

Also, once you have the steering shaft removed from the gearbox, this tube will be totally unprotected and it sticks out of the gearbox quite a bit. Be extra careful not to damage it and whatever you do, don't drop the housing!

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Some of these bolts pass through the housing and into the interior of the gearbox and these bolts will require sealant when we close up the box for good. Otherwise, the lubricant will migrate up the threads and out of the box. By the way, these bolts have a soft, flat washer without a lock washer. I'm sure the theory was the use of flat washers would help keep a good seal.

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With the bolts removed and a gentle tap, the cover comes off. Yes, it looks nasty and someone even introduced some grease into this box (which is a no-no) but what I don't see is any milky lube so I'm betting things are going to be pretty good down in there.

Luckily, despite the fact that the steering gear shaft was open to the elements, it was filled with dirt - so much so that water just never got down into the gearbox.

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Off comes the steering column's outer tube, the Steering Gear Jacket. I made a mistake last night when I laid this whole thing down on its side and because of the angle it was at, some of that lube made it up into the steering column. So, I made some extra work for myself - additional cleanup. Bummer.

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Original gasket still in place and some of the thread sealer can be seen, still on the inside of the cover. Dare we reuse the gasket? Mmmm..probably not. A new gasket comes with the rebuild kit anyway.

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Pitman Arm Adjusting Screw and lock nut.

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Pitman Arm Shaft coming up and out.

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Some wear on the tapered studs but this is just about what I'd expect from a 67 year old truck.

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Goopy, rather ugly looking lube, but actually, it's still just about the right consistency - very much like the consistency of honey.

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Upper Housing Cover. This has shims beneath it and these are what set the end play of the steering gear shaft. The three bolts that hold it on are to be torqued to spec so before you reassemble, ensure that you have good, healthy bolts.

With a variety of shims (and I've ordered a kit that comes with shims) what you are trying to achieve is a steering gear shaft that moves freely and yet has no end play, meaning the steering gear shaft moves neither up, nor down.

Why not just use the combined shims that came on this box? Well, I'll be replacing the ball bearings and perhaps even the upper and lower bearing cups so that will almost certainly change the height of the steering gear shaft relative to the housing. We shall see.

Upon reassembly, I'll be shooting for "no end play" which seems rather definite and leave the rather vague interpretation of "moves freely" out of it. We just know we don't want it bound up. As with we did with setting the preload of the king pin bearings, it will likely take several tries to get it just right, which is really no big deal as all of that will take place on the work bench. My old back can use a few easy jobs.

It is very important that you take good care of these shims while everything is apart. Now we are almost ready to take the steering shaft out of the housing. There are going to be ball bearings in the next step - possibly loose ones. You should find them organized in a rather clever little plastic retaining ring but beware - anything is possible on these older trucks. Take great care to make sure not to lose any ball bearings before removing the steering shaft from the housing! If all the parts were present in this steering gearbox (and they are not because someone has been in this box before me) there would be two clips, one at the base of each bearing cup and they would hold everything together as a unit so when you extracted the shaft from the housing, bearings and cups would come out with it.

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With the Pitman Arm Shaft and the Upper Housing Cover (and shims) removed it is now possible to draw the Steering Shaft directly up and out of the housing. In doing so, the Cam Shaft Cup (which is the cup for the ball bearings) and ball bearings will come with it as they are laying on top of the Steering Gear Cam Shaft (the worm gear).

Things are probably slathered in lube so it will be hard to determine what is going on with those bearings. My suggestion is that you prepare for the worst case scenario and be working over a tray of some kind and maybe even a magnet just in case. Wrap those bearings with a rag as soon as they clear the top of the gearbox housing and keep them secure. If they are still arranged in their plastic retaining ring, carefully draw them and the bearing cup up and off the steering gear shaft.

In this photo, you can see I have removed the bearings and their cup so you can get a better look at them. These might be something you want to re-use but some of the rebuild kits will offer you sets of new ones so if things go badly, don't panic. Replacements can be had.

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Now, the oil tube I described earlier, shown here as it resides inside the housing except that when everything is assembled, the oil tube is inside the Steering Gear Shaft. The sump at the far right of this photo is pretty much the lowest point in the gearbox. There was quite a bit of dirt and grime in there, but happily, no rust.

Immediately above that sump is the lower bearing cup. The lower ball bearings are organized in a plastic ring just like the upper bearings and they sit in that bearing cup and the base of the Steering Gear Cam (worm gear) rests upon them.

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See the Pitman Arm Shaft bearing? It is a bushing-type bearing of yellow metal. There is a shadow on it which is a wear pattern. There's a lot of load on those bearings when things are turning and it is very important that they be as good as they can be. These will be replaced and I'll show the removal process in detail. Because there are yellow metals in the steering gear box I will need to ensure the new lubricant I use will not harm them over time. Some of the more modern formulas will. At this point I don't know exactly what I am going to use but I can tell you that this is NOT the place for 90wt, nor is it the place for chassis grease!

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Pitman Arm Shaft oil seal. This one has held up extraordinarily well over the years and has done its job proudly even though the bushings are worn. I know what you want to ask. Could we get by with reusing the bushings if the oil seal has been able to accommodate the wear? The answer is, Yes...but only until the wear becomes too great and we are quite clearly headed in that direction, right? I don't know where the tipping point is and I don't want to have to find out after I've put everything back together. Better to replace these bushings and seals now and be done with it.

Image

I apologize for the photo and I'll try to remember to retake this one. Have a look at the opening where the Pitman Arm Shaft passes through the housing (lower left corner of the photo). There are two bushings (or bearings); an inner and an outer with a gap between them. One bushing is a long bushing and the other, a shorter bushing. In the space between those two bushings there is a passage in the casting (in the photo, it's at about the 1 o'clock position) and that passage allows lubricant to get into the gap between the two bushings so as to lube the Pitman Arm Shaft. In the event you install replacement bushings in the wrong order, the longer bushing will very likely cover that hole. Something to think about.

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Here is the result of having a Pitman Arm installed off-center. *CLUNK* The Pitman Arm Shaft goes full over and the tapered stud bangs into the interior of the casting before the steering knuckle hits the stops. The TM says to count the number of turns lock to lock and come back half that to ensure the gearbox is centered before installing the Pitman Arm. Don't skip that step!

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And there's the dent where the tapered stud had been hitting. I'm quite sure this is very old damage as the steering has been fairly well centered since we got it and both sides went all the way to the stops but at some point, somebody had screwed it up.

Image :D

Cheers!
TJ
Last edited by m3a1 on May 7th, 2018, 9:12 pm, edited 6 times in total.
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Re: M38 - Nothing at all to do with M151s

Postby m3a1 » April 23rd, 2018, 6:01 pm

One of the benefits of NOT having all the parts ready to go is it forces you to slow your roll. So I spent today doing all the extra things that were needed to make this part of the Willys project go in the right direction.

Today was the final disassembly and cleaning of the steering gearbox. There were a lot of things to do and it took quite a bit of time to get it done.

As promised, here are a couple of pictures of the oil pipe as it secures to the cap at the end of the steering gearbox. My comment earlier was, upon cleanup, be careful around this end of the pipe. You don't want to damage it.

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Here we have the Steering Gear Cam with its supporting bearings properly oriented. The top (left) has the bearing cup in place (the bottom's bearing cup is still in the housing).

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The ball bearings can be popped out of the ring that organizes them and new balls popped back in. I'll be replacing them all. The top ball bearings look great. The bottom ball bearings look dull and have some very tiny rust spots on them.

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The oil pipe extends well up into the steering shaft and terminates well above the oil bath in the steering gearbox. Thus, a good portion of the oil pipe is subject to rust and corrosion.

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I didn't mention the washers on these bolts yesterday but like the ones on the side cover, they are also flat washers, rather than lock washers.

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Here is the top bearing cup, properly oriented to the housing.

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Upper Housing Cover, upon which rests assorted shims....

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....and the upper Cam Shaft Thrust Cup (bearing cup). The Upper Housing Cover presses upon the upper Cam Shaft Thrust Cup and the shims limit how much force it can exert upon the Cam Shaft Thrust Cup.

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....and the upper bearings.

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And here we have the lower Cam Shaft Thrust Cup (bearing cup) and bearings oriented properly within the housing.

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Now is a very good time to loosen the pipe plug which always seem to be screwed in too tight. Do the next guy a favor. Use a little thread sealer and don't screw it in gorilla tight.

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The next two shots are of the oil passage from the internals of the housing to the area between the two bearings for the Pitman Arm Shaft.

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Ok, here is where I ran into a little difficulty and there is some important information for you in the next set of photos. I tried to follow the removal procedure for the Pitman Arm Shaft Bearings, as set forth in the TM but could not find where the bearing was bisected which would have been the correct place to begin. As a result, I found I was simply drifting the inner bearing down and against the other bearing. But things WERE moving. So, rather than blindly follow through with what was clearly turning out to be a bad effort I got a socket of a suitable size and pressed both bearings straight out.

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At the far end of the bearing you can see where the two helical grooves are cut into the inside of the bearing. Precisely half way between those grooves is where the bearing is bisected. You may not be able to see that bisection when the bearing is in place, but now you know where it is. Unfortunately, I didn't have that information. No harm done though and as we said before, there is more than one way to skin a cat!

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This paper is a mock-up of the bearing so that what I just described may be more easily seen.

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This surprised me. Except for the metal you see on the top face of this seal (which is a small washer to which the rubber seal has been vulcanized) everything else is rubber; the seal face, the sides, the whole bit. But, when you consider this is just to seal a shaft that turns only a few degrees this way and that, this is really all you'd need, eh? With this manner of construction there is something to consider and that is, when installing a new seal, it may be in your best interest to put some light adhesive in place where the sides of the seal rest against the housing. After I had the opportunity to look at replacement parts I began to think this seal is from another, later Willys application. I did a very fine job while it was in there.

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We will be removing that bearing cup, I promise!

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And here is how it looks with the Pitman Arm Shaft bearings and seal removed. There's the all-important hole for lubrication.

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Back to the oil pipe. The end that exists outside the oil bath has become rusty and we need to put a stop to that.

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So, an application of Ospho (phosphoric acid) gets laid on and allowed to work it's magic. I may lay on a thin coating of varnish before reassembly.

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And since the reason for that rust is because the interior of the Steering Gear Shaft has become clogged with dirt and rust and all sorts of junk. The best way to deal with it is to treat it just as you would a rifle barrel.

I spent about two hours on sorting this out. I used everything from PB Blaster to Gunscrubber, acetone....the works. The process terminated with a final scrubbing with hot, soapy water and a high pressure rinse. I then laid it out in the sun on an incline until everything dried and then laid on a generous application of metal preservative. Two hours seems like a lot but I think it was time well spent.

Initially, that bore brush was coming out completely full of junk! All this work because someone couldn't bring themselves to spend a few measly dollars on a replacement horn button. Of course, with some of the low quality reproduction stuff coming out, I really don't expect my new horn button to last, either. You can be sure of one thing. I'm going to do my level best to ensure the interior of this stays clean and dry from now on.

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The moment you've all been waiting for. The lower bearing cup is coming out. I inverted the housing and with a dead blow hammer, stuck the bottom of the housing. Inertia brings the bearing cup out. It is a very fine tolerance and PB Blaster can be a big help in this process. If your housing is rusty down there you may have to engineer a way to pull it out but however you remove it, it has to come out perfectly straight.

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It is exactly the same size as the upper bearing cup.

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As we can see, there's still a lot of crud down in there to be cleaned out. Parts are on the way and we'll soon be into the reassembly.

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Has this been hard work? Absolutely not. Could anyone with basic mechanical skills do it? Sure! Does it require special tools? Nope. So, if you have a steering gearbox that needs a do-over my recommendation is - DO IT!

Cheers,
TJ
Last edited by m3a1 on May 7th, 2018, 8:33 pm, edited 1 time in total.
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Re: M38 - Nothing at all to do with M151s

Postby m3a1 » April 27th, 2018, 9:34 pm

Ok, here's a little update. Some parts are in and here's the rebuild kit.

Image

As you can see here, the splines on that new shaft are FAR healthier than the old one, whose splines are high in the middle and low on either end - part of what is causing the wobble on the pitman arm. In that condition, there is just no way to get it tight enough to seat well. This is chiefly what got me into the rebuild of this box.

Image

I know. I know. I just can't get good focus for the tight shots but if you look, the wear on the old studs is pretty obvious. The wear wasn't a deal-breaker but with the splines all messed up, everything goes bye-bye.

As an aside, I read where one fellow claims he had these studs pressed out, rotated 180 degrees and pressed back in again. Wow. Crazy?...or dedicated to the cause? You decide.

Image

The new seal is more like what we're used to seeing, however, it has one point of contact against the shaft, whereas the older one has two. I don't know what is "right" but this is nothing like what I pulled out of the steering gear box.

Image

Once again, my camera fails me. What I was trying to show you was the difference in the lubrication groove. In the old bearing/bushing, it has a helical cut with very acute edges and the groove doesn't go all the way across but terminates before it reaches the end, perhaps because that end is where the outer seal is. In the new one, the lubrication groove is very wide, runs the whole length of the bearing and has tapered edges. Oddly, that new groove doesn't look quite as deep to me but it could be the coloration.

Image

And so, having my lovely new parts I went right to the business of carefully pressing the new shaft bushings in. Got those done with no dramas and then, the moment of truth. NOPE. The shaft won't go in.

Well, we knew these were going to have to be reamed but can one get away with reaming these by hand? The specs say we're looking to achieve between .0005" and .0025". Let's just say that's a pretty close fit. Now, I'm good, but I'm not THAT good and so, having a rather stellar machinist in town who takes on extra work at home when he's not machinist-ing for regular paycheck, I delivered it to him to sort that out for me. When it's all done, I'll share with you what it cost and let YOU decide whether or not it's worth it.

Now, if I were a hundred miles from the nearest machinist, I'd go for it but here's the rub. FIRST you have to know exactly how big your shaft is and only then can you procure a reamer, preferably one that's adjustable. SECOND, there is the matter of ensuring that your process reams out both bushings perfectly in line with one another. So, in my mind, this is a matter best left to the experts and machinists can only exist if they get paid once in a while.

Support your local machinist!

My guy's initial inspection revealed that the bushings were "egg-shaped" (measured in very, very tiny amounts, like, a decimal point and lots and lots of zeros) but such are the intricacies of fine machine work. What is small to us is huge to them and such matters are best left to the professionals....bless 'em all.

No, I didn't chicken out. I used good judgement, and while I am at the coast, basking in the sun and drinking those drinks with the little umbrellas in 'em, some other guy can do some work on my truck.
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Re: M38 - Nothing at all to do with M151s

Postby m3a1 » April 28th, 2018, 6:52 am

On a slightly different topic (eye protection) I finally caved in and had a piece of metal removed from my eye yesterday. I've always been rather indifferent to pain which is something that drove my parents (and my wife) kind of crazy over the years but when I knew I'd be going to the coast for a few days with its constant wind, the thought of dealing with that was just too much to bear.

So, with a visit to my optometrist and $80 later I'm good to go. That's $80 I might have put into the Jeep.

When the incident occurred, YES, I was using eye-pro but what I didn't expect was the tiniest little piece of metal getting right past my glasses, probably at the bridge of the nose.

I've been through this before and have made a point of having lots of eye-pro around - enough to have one ready at every work station - and yet apparently not the right kind. So, live and learn. I'll be doubling down and getting some full face shields instead of glasses, especially for those places where I'm grinding metal.

Cheers,
TJ
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Re: M38 - Nothing at all to do with M151s

Postby Mark » April 28th, 2018, 7:21 am

Ya I had a piece of aluminum get stuck in my eye, had safety glasses on, was on the ground watching lineman work on top of a 100 foot pole with conductors.So go figure
mark


1968 m274A5
1960 m151
1981 m151A2
1964 m416
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Re: M38 - Nothing at all to do with M151s

Postby Hambone » April 28th, 2018, 8:49 am

TJ, you can walk on a wooden leg but you can't see out of a glass eye, best $80 you could spend.
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Re: M38 - Nothing at all to do with M151s

Postby m3a1 » April 28th, 2018, 10:10 pm

Well, the thing is, at the time of occurrence I can't recall that I was even aware of it and what with the eye pro in use, later when things became uncomfortable I just couldn't imagine that it was a piece of metal and what's more, it felt like it was moving around so I was kind of waiting for it (whatever 'it' was) to find it's own way out. It may very well have been moving around and finally took root, too. Anyway, I found out patience wasn't going to help make it go away.

And now, I have two new full face shields and three new sets of seals-to-the-face goggles. I could have used that $80 elsewhere, doggone it. :oops:

And THIS year, I'm adding lots of names to my Christmas Card Distribution List... My machinist... My optometrist... :lol: :lol: :lol:
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Re: M38 - Nothing at all to do with M151s

Postby rickf » April 29th, 2018, 7:57 am

Better add your X-Ray tech because you will need them before you get and MRI so you don't scramble your eyeballs in the MRI machine with a missed piece of steel. Considering your advanced age you will be in that tube more and more often.
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Re: M38 - Nothing at all to do with M151s

Postby m3a1 » May 6th, 2018, 5:44 pm

For those of you looking for additional information on these old Ross steering gearboxes -

https://www.keepandshare.com/doc/499400 ... 0-meg?da=y
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Re: M38 - Nothing at all to do with M151s

Postby m3a1 » May 6th, 2018, 5:45 pm

Ok, here's a little update. Some parts are in and here's the rebuild kit.

Image

As you can see here, the splines on that new shaft are FAR healthier than the old one, whose splines are high in the middle and low on either end - part of what is causing the wobble on the pitman arm. In that condition, there is just no way to get it tight enough to seat well. This is chiefly what got me into the rebuild of this box.

Image

I know. I know. I just can't get good focus for the tight shots but if you look, the wear on the old studs is pretty obvious. The wear wasn't a deal-breaker but with the splines all messed up, everything goes bye-bye.

As an aside, I read where one fellow claims he had these studs pressed out, rotated 180 degrees and pressed back in again. Wow. Crazy?...or dedicated to the cause? You decide.

Image

The new seal is more like what we're used to seeing, however, it has one point of contact against the shaft, whereas the older one has two. I don't know what is "right" but this is nothing like what I pulled out of the steering gear box.

Image

Once again, my camera fails me. What I was trying to show you was the difference in the lubrication groove. In the old bearing/bushing, it has a helical cut with very acute edges and the groove doesn't go all the way across but terminates before it reaches the end, perhaps because that end is where the outer seal is. In the new one, the lubrication groove is very wide, runs the whole length of the bearing and has tapered edges. Oddly, that new groove doesn't look quite as deep to me but it could be the coloration.

Image

And so, having my lovely new parts I went right to the business of carefully pressing the new shaft bushings in. Got those done with no dramas and then, the moment of truth. NOPE. The shaft won't go in.

Well, we knew these were going to have to be reamed but can one get away with reaming these by hand? The specs say we're looking to achieve between .0005" and .0025". Let's just say that's a pretty close fit. Now, I'm good, but I'm not THAT good and so, having a rather stellar machinist in town who takes on extra work at home when he's not machinist-ing for regular paycheck, I delivered it to him to sort that out for me. When it's all done, I'll share with you what it cost and let YOU decide whether or not it's worth it.

Now, if I were a hundred miles from the nearest machinist, I'd go for it but here's the rub. FIRST you have to know exactly how big your shaft is and only then can you procure a reamer, preferably one that's adjustable. SECOND, there is the matter of ensuring that your process reams out both bushings perfectly in line with one another. So, in my mind, this is a matter best left to the experts and machinists can only exist if they get paid once in a while.

Support your local machinist!

My guy's initial inspection revealed that the bushings were "egg-shaped" (measured in very, very tiny amounts, like, a decimal point and lots and lots of zeros) but such are the intricacies of fine machine work. What is small to us is huge to them and such matters are best left to the professionals....bless 'em all.

No, I didn't chicken out. I used good judgement, and while I am at the coast, basking in the sun and drinking those drinks with the little umbrellas in 'em, some other guy can do some work on my truck.

Cheers,
TJ
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Re: M38 - Nothing at all to do with M151s

Postby m3a1 » May 6th, 2018, 5:46 pm

On a slightly different topic (eye protection) I finally caved in and had a piece of metal removed from my eye yesterday. I've always been rather indifferent to pain which is something that drove my parents (and my wife) kind of crazy over the years but when I knew I'd be going to the coast for a few days with its constant wind, the thought of dealing with that was just too much to bear.

So, with a visit to my optometrist and $80 later I'm good to go. That's $80 I might have put into the Jeep.

When the incident occurred, YES, I was using eye-pro but what I didn't expect was the tiniest little piece of metal getting right past my glasses, probably at the bridge of the nose.

I've been through this before and have made a point of having lots of eye-pro around - enough to have one ready at every work station - and yet apparently not the right kind. So, live and learn. I'll be doubling down and getting some full face shields instead of glasses, especially for those places where I'm grinding metal.

Cheers,
TJ
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Re: M38 - Nothing at all to do with M151s

Postby m3a1 » May 6th, 2018, 5:47 pm

On the topic of steering gearbox lube - I did my homework. I read about this till blood was squirting out of my eyes. This is certainly not my area of expertise. I am not hanging my hat on what is correct based on the TM, simply because we have lubricants available to us now that simply did not exist back then.

Of course, an important thing to keep in mind when selecting the "correct" lubricant is that this is not a high-speed gearbox and I can see how some fellows erroneously conclude that chassis grease might work since this is a low speed application. Among the many reasons why chassis grease does NOT work is that a "correct" steering gearbox lubricant must be able to efficiently follow the bits and pieces as they move around in the gearbox, leaving no voids. Thus, we are looking for a lubricant that is more oil-like than grease-like....something that is a bit like honey.

As has already been discussed at great length, grease will simply push out and not return to the areas requiring lubrication.) My advice to anyone who has introduced grease into their steering gearbox is that they take the time to remove it.

Also, the "correct" lubricant would benefit from having the same qualities over a broad range of temperatures. This has been achieved with many modern lubricants. So, arguably, with the "correct" modern lube, the need for changing gearbox lubricants for seasonal purposes can be eliminated from your bi-annual maintenance list. These things were on my mind.

I started with the following. Found it interesting but it can be a bit misleading especially if you assume viscosity is all there is to it -

https://www.glennbennettcorp.com/hubfs/ ... erence.pdf

This next, very scholarly piece helped a lot, particularly this simple phrase which I used as a guide "Generally speaking, a high-quality worm drive lubricant will have low friction, high oxidation resistance, good anti-wear protection and high viscosity index." I don't pretend to understand all of the article but I think I got what I needed out of it -

http://www.machinerylubrication.com/Rea ... worm-gears

I also revisited the topic on the CJ2A forum where a lot of opinions were shared. -

Then I went to youtube and saw HOW the tests (applicable to the product I'm presently considering) were performed. They also show what the resulting damages are. The first two tests take place at very high speeds -

https://www.youtube.com/watch?v=kEv1hSJTQTM

https://www.youtube.com/watch?v=eLcy5YHDNbo

https://www.youtube.com/watch?v=uniCjnOg7mE

And, through the power of the internet, I finally came upon this synthetic (!!!) the qualities of which I'm presently discussing with my buddy, who is an honest to God chemist and who worked at places like Red River refurbishing military stuff. The information provided on the technical data sheet of these products is really important and if you are serious about finding out about your lubricant, you absolutely must look at that.

https://www.amazon.com/gp/product/B00LX ... UTF8&psc=1

Technical Data Sheet. What I'd like the reader to take away from this are the PROPERTIES of the product. Point of interest, in the product I'm presently examining, ISO 460 has a slightly higher viscosity than ISO 680, yet 680 is a bit better performer in the scar test (so viscosity isn't all there is to it, right?)

http://www.super-lube.com/files/pdfs/Te ... ar_Oil.pdf

In my physical searching, I learned that what we generally would require for steering gearbox lube is really not to be found on the shelves of auto parts stores in any amount, chiefly because its popular use has been lost to antiquity. This doesn't mean it's not out there. It simply means that we may be looking in the wrong place, eh?

I learned that the term "Food Grade" is not to be automatically dismissed as something that is necessarily WRONG for those of us in the automotive world. In fact, the use of additives like sulfur and phosphorous is a huge no-no when it comes to the formulation of food grade lubricants (the FDA obviously frowns upon it), SO, finding a food-grade lubricant that we can use (one that is H1-rated) is VERY good indeed!

The key point of the following link was the general discussion of the H1 rating (An H1 rating has been achieved by the synthetic lubricant I'm considering) -

http://www.machinerylubrication.com/Rea ... lubricants

One of my main parameters is that the lube do its job (beyond the obvious lubrication performance issues) - that it will not be prone to leaking, that it will not be damaging yellow metals, that it will not be degrading over time.

Another thing high on my list is that the lube be readily available, not only for myself, but also for the NEXT guy who owns this truck. Procuring some mysterious lube from someplace that is never to be found again really doesn't help that guy.

And so, in the time it took me to write this, the decision has finally been made. Super Lube 54632 Synthetic Gear Oil ISO 680, 1 quart Bottle, Translucent, is the product I selected for use in my steering gearbox. It will be several days before it arrives but when it does, I'll share some photos.

Cheers,
TJ
m3a1
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Re: M38 - Nothing at all to do with M151s

Postby m3a1 » May 6th, 2018, 5:49 pm

Sorry. There has been a delay in posting, owing to my son having to spend some time in the hospital.

My lubricant came in and it's really interesting stuff. Viscosity-wise this flows more like thick maple syrup than honey...and just as sticky! As I mentioned, this product meets all the specifications I was looking for in a lubricant, so I'm a happy camper.

As you know, the reaming of the bearing/bushings for the output shaft was completed and we found them to be out of round when pressed into place. Reaming not only brought them into the correct tolerance, but also took down the high spots. Knowing what I know now, I might have gone to greater lengths to procure a set of NOS parts but with what I have, I'm sufficiently satisfied to forge ahead with the business at hand.

Next, I decided to have a good hard look at the upper and lower bearings.

I was dissatisfied with the bearing cups that came in the kit. They are machined in such a way that the bearings have only two points of contact and I felt those surfaces were simply not machined to the same smooth, quality finish as the originals. The original bearing cups actually cradle the bearing surface across one quarter of its diameter and are machined to a much smoother finish , not to mention they are proper mates to the bearing cups on the steering shaft.

So, with the intent to reuse the original cups, I got a micrometer and checked the new bearings and found them to be just a tiny bit larger than what I pulled out (in the tens of thousandths) and so, elected to pop the old bearings out of their retaining ring and pop the new ones in. The most obvious benefit is going to be that final assembly is going to be far easier than trying to herd all those ball bearings into position and keep them there while everything is going back together. I also believe the life of my new bearings is going to be extended by having their working load spread across a larger surface.

As a small sidebar comment, you may have noticed that as yet, I've made no mention of the retaining clips for the bearing cups. Such clips serve to keep the steering gear shaft with it's attendant bearings, assembled as a unit, speeding assembly and disassembly. My gearbox did not have them which suggests to me that someone has been in there before. My gearbox got along fine without them and at the moment, I've no plans to replace them. I only bring this up because they are mentioned in the TM and no, I did not overlook them.

The trickle down effect of changing the ball bearings out is that I can no longer assume that the preload is correct. Happily, the kit I purchased provides a whole set of brand new shims for accomplishing that.

As always, when it comes to sourcing parts, you get what you pay for.

In the photo below -
Top center - original (dull) lower ball bearings to the left of the new bearing cup and new ball bearings to the right. They have most likely lost their luster due to particulates that gathered in the lower regions of the gearbox.

Center - original bearing cup

Left - original top ball bearings, still quite shiny and in good order.

Right - original bearing guide with new ball bearings in place. This mates to the bearing cup in the center.

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Re: M38 - Nothing at all to do with M151s

Postby m3a1 » June 25th, 2018, 7:06 pm

The hold up on the steering gear box has been the fact that I keep getting sidetracked on getting the column refinished. This stripper does a good job and is very manageable. Get it on your skin accidentally and it causes no problems. It even removes grease and old fuel varnish.

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