I've heard of some folks running without the pin in the u joint. Heard of lots of others say the pin was sheared when they took it apart and had unknowingly been running that way. Just curious how common this is.
Hal, when I rebuilt my rear axle last winter the pin was missing. Not sheared off just not there. It has one now.
Square hole square shank so shearing is not possible
I left them out as i replaced the driveshaft bushing i dont have the tooling to face it
Doesnt seem be an issue
If you are running a stock Ford pinion bearing, then it needs the pin.
It needs the pin no matter what pinion setup you run.
Nobody should be running without the pin.
Without the pin the U joint will probably eat up the driveshaft bushing by going in and out like a grinder. The U joint is not a throw out bearing in a clutch and needs to be locked in place or it will constantly wear the face off the bushing. The U joint is to only spin and not to move front and back while doing so.
I could be wrong but don't think so.
I have been running for 15 years without a pin and so far no problems, Fred Houston did not use a pin in his cars.
It is that pin which holds the pinion gear in alignment with the ring gear with the standard type pinion bearings. It could very possibly cause premature wear on the gears if you run without the pin.
In theory, the Fun Projects bearing setup does not have to have the pin. However, many people say it really should have it regardless, and I agree with them. I have not communicated personally with John R on this subject, however, my understanding is that he recommends having the pin in place (definitely NOT speaking for him, if in doubt, check with him directly).
In the for what it is worth department, I have seen the pin sheared off myself a couple times. Once with a pin I personally had put in a few years earlier. Analysis indicated that the steel pin was of very hard material and probably fractured when I hammered it in place. Always since, I make sure the pins I use are a medium soft steel.
The stock bearing arrangement should NEVER be run any significant distance without the pin in place. Yeah, the ring/pinion gears do tend to push the driveshaft forward with running. One may think that alone should make it okay to run without the pin. However, the reality is that under certain conditions, the driveshaft will float back, and that will allow the ring and pinion gears to run tight and bind a bit. Binding can result in undercutting the teeth (Rich B has recently seen some of that), and eventually will severely damage either or both gears depending a bit on the relative hardness.
The other one I saw, was I took a rear end apart years ago that was missing the pin. The gears were junk, and the driveshaft had worked its way back enough that the differential carrier had ground the end off the driveshaft back far enough that the cotter pin had been ground away.
The silly thing about that one was, that other than the very end of the threads, that was one of the most perfect driveshafts I have ever seen. So I used it. I drilled a cotter pin hole through the nut back just a bit.
Pin the U-joint.
I'm installing a KC Warford in my 1924 TT C-Cab chassis. The good folks at Layne Machine Works included the shortening of my driveshaft in the price, but left the final fitting of the U-Joint up to me. After test assembling the rear end and attaching it to the chassis I marked where the U-Joint pin needed be placed. The assembly was disassembled and the U-Joint pin hole drilled. The rear end was re-assembled and permanently installed with the U-Joint pinned to the driveshaft.
Side note; The cast iron Warford even has a hole and matching plugs in the casting to fit a pin for the U-joint on the input shaft. And yes I installed one in mine.
No pin in my touring ujoint, but I have a double tapered roller bearing arrangement in the pinion spool. Been that way for about the last 18 years and probably around 60,000 miles. If you run the stock Hyatt/roller bearing thrust pinion bearing, you MUST pin the ujoint.
The pin is definitely required as previously mentioned. With the factory set up the combination of the pin, universal joint thrust face and the top bush prevents the pinion moving into the crown wheel too deep when under engine braking conditions The ball bearing race at the bottom caters for the forward thrust when accelerating when the pinion gear try’s to move forward away from the crown wheel. John Reagan’s set up doesn’t require an accurate “no end float / no preload” on the drive shaft however I did both and with a Uni pin. It’s called a belt n braces approach!
Alan 8n Western Australia
I've got the FP pinion bearing. I'm reusing it from a previous rebuild. I'm putting in a new ring and pinion. After getting it all ready to go back together the pin hole doesn't line up. I could reface the bushing, but the hole in the driveshaft is so far aft, I'm not sure the pin can be installed through the hole in the torque tube. It's off by at least 1/16" from the u joint hole, which is already further aft than center. I knew I had heard of people running without the pin. I'm tired of messing with this thing. Think I'll just leave it out. It obviously works for some.
Hal, you could still use the pin easily enough by giving the U-joint a quarter turn then marking and drilling a new pin hole.
That crossed my mind, but I'm not sure how much it would weaken it. The holes would interact in the middle.
So the shaft moves without the pin in the standard set-up but the FP bearing holds it in place? No one has said how. Never installed or saw one.
Charlie- the FP bearing setup has a lock ring that holds everything in alignment and in place. The u joint pin holds the original ford setup in place. I feel that the pin should be used- why would anyone want the u-joint to be able to float on the shaft? Just because some guys have had it that way for "years" doesn't mean it's a good idea.
There's a tapered roller bearing in the FP kit that is in the rear part of the spool. It takes the thrust that tends to push the driveshaft forward. It comes with shims to set the pinion depth. To keep the driveshaft from moving rearward, there is a lock collar in front of the sealed ball bearing that is in the front part of the spool. So with it all assembled, the drive shaft cannot move. The u joint does not have to keep the driveshaft from sliding rearward as in the original set up. In other words, you could face the front bushing way deeper than needed, and not have goofed anything up.
Tim, it's not that I WANT it to float. It's just a matter of I dont want to have to pull it all apart and try to figure a way around my problem, which would probably be shimming the ring gear, or else moving all the thrust bearing shims to one side thereby putting the axle off center. It's a balance between my laziness and the potential harm. Im thinking the potential harm is minimal, so my laziness won out.
Could it be for the assembly line? If they hung the rear end with the drive shaft tube down while transporting it to the line. This would keep it from falling out.
Just a thought.
Hal: "That crossed my mind, but I'm not sure how much it would weaken it. The holes would interact in the middle."
True enough, but I expect weakening would be very minimal — you're relying on the corners of the square for torque transmission, not the centre.
A little late to illustrate Wayne's post, but here's a look at the pinion we were discussing.
Why would you not use the Pin on a stock setup? I've always thought that by not using that the thrust on the bronze drive shaft bushing would wear and cause eventual misalignment of pinion gear and would cause wear problems on gear end.. Maybe we don't drive enough to matter. Who knows
The thrust on the pinion is always outboard. There is no need for the pin in the final assembly. It does give the pinion a
fixed position which keeps the assembly together and makes setting the ring gear clearance easier.
You are 100% correct in your thinking.
Not true. Sure wish I had the photos to show you of a driveshaft with the nut rubbed down to 1/2 its thickness and the threaded end worn away so far that the cotter pin hole was gone.
Come on guys, why would you leave this out? It's a simple little pin that takes 15 minutes to install. What are you trying to prove? Assemble the car the way it was intended. The Ford engineers were smart guys, why second guess them?
I've been selling parts for 30+ years and I have always been amazed and intrigued by the phenomenon of guys eliminating OE parts. Their justificatins are even more entertaining. If it came with it from the factory why wouldn't you put it back on? I think it's a matter of cutting corners. I just don't get it...
Nobody's mentioned a roll pin, which installs in 1 minute, and does the job just fine in this application. It also makes any future disassembly easier.
Tim R, I bought a (modern by my standards) used pickup many (many) years ago. It had a new clutch installed because although very low mileage, the PO didn't know how to use a clutch correctly. I (of course) inspected the workmanship. Only about 2/3 of all the bolts were used. Three bolts held the big four-speed onto the bell housing, only three bolts kept the top cover in place. A couple were missing in the other end of the bell housing, some parts were held on using only half their screws. I scrounged up bolts and screws that fit from my supply and filled most of the holes. But a few were hard to reach with everything else in the way.
Those last few resolved themselves about a year later when the "new" clutch blew to pieces, and I had to pull the whole assembly clear out and replace almost everything.
The reason the clutch blew? Well, the whole year, that clutch just didn't work properly. Had a nasty tendency to "hop" in reverse. Turned out, the "bright bulb" that had put in the new clutch (before I got the thing) had put the clutch disc in backwards. Now, I had always been told that was basically impossible to do. The spline center in the disc is off center so that it will only go in one way (I confirmed this with the new-new disc I put in). But the "smart guy" before me managed to get it in backwards. The reason for hopping in reverse? The disc being in backwards loaded the cushion springs the wrong way.
I wonder if the lack of bolts and managing to get the disc in backwards were related?
Now. Let us take a closer look at Rich B's pinion gear. The exact source for this gear is (i think) not known. But the teeth on this gear tell a story.
Beginning with the tooth closest to his hand, which clearly shows the whole one side of the tooth. Look closely at the bottom of the tooth, near the flat valley between this and the next tooth. On the larger end of the gear, the surface has begun to flake away. Look closely toward the narrower end, and you can see that the wear runs the full length of the tooth, but not quite reaching the bottom of the tooth. That tooth has been "under-cut" by the teeth in the ring gear. Had it run a few thousand more miles, that flaking would run the length of the tooth, and become much deeper as well. I have had a few pinion gears over the years that had whole sides of teeth chewed out.
On the (by modern standards of quality machining) crude square cut gear teeth of the model T era, such "under-cutting" can be caused by the ring and pinion spacing being either too tight (close), or too loose (far apart).
The next tooth (we see both top and side well), shows flaking of the surface, and uneven wear. I can't say for sure if it is being cut in at the base or not. All of this could be due largely to being a bit soft (not hardened enough), or misalignment of the gears, and probably a little of both.
The tooth front and center (nearest his finger tips) shows serious alignment issues. On the larger end of the gear, both the leading and trailing sides of the tooth are rolling up. Also a sign of misalignment of the gears. And also a sign of a slightly soft gear.
The next tooth also shows some flaking of the surface, this time on the trailing side which has the lightest load most of the time.
All together, this pinion gear was likely not hardened enough when new. It is important to remember that hardening technology at that time was good, but not as precise as can be accomplished today. It is common for model T rear end gears to have uneven wear due to inconsistencies in the hardening. But this gear also shows some misalignment issues.
Whether it could have run without a pin in the U-joint? I think I would be afraid to hazard a guess. (It probably did not, but could have given some of the wear patterns.)
The truth is. This gear could be carefully installed to run against a slightly worn ring gear, with positioning as close to a proper balance as the wear will allow, and run for many thousands more miles. It would probably (if properly adjusted) outlast most of us that would drive it. But a better choice would be to get a better gear.
One more thing.
While it is true that the normal thrust under load between the ring and the pinion gear is to push the pinion gear outward (forward). And this factor makes the pin unnecessary (in theory), that fact is only when there is a load on the drive-line (torque either forward or backward). In reality, every time you throttle back a little, many times when the road surface changes incline, has bumps, even a strong tailwind. When the load neutralizes, the spinning heavy rod inside a lubricated tube, quickly tries to slide downhill. For those moments, sometimes several seconds, the driveshaft floats back, and gears run improperly aligned, with the heavier part of the pinion teeth (the wider end) running into the lighter areas of the ring gear. This does cause under-cutting of the teeth, and other wear pattern problems.
Jerry VO and I have both found driveshafts that ground the end off clear to the cotter pin. Do you really want to make one for yourself?
And again. Yes, some of the modern double-thrust pinion bearing replacements (which are a good improvement for our Ts) may not require that pin? But I still think it is a good idea. But then I have worn suspenders with my belt a few times.
Well I guess you could run a T with just 2 bots to hold the demountable rims on instead of four. Just make sure you put the 2 bolts on opposite from each other! ???????
You honestly equate using 2 lug nuts to leaving out the pin in a u joint even when using the modern pinion bearing? I can predict what would happen if you left off two lug nuts. You care to predict what will happen from me leaving out the pin on the u joint when using the modern pinion bearing setup?
I'll take a stab
With the original set up, the ujoint will slide very slightly within the output shaft, as designed, when the axle is exercised up and down.
Without the pin to hold the shaft stationary, axially, as well as hold the u-joint stationary axially, the u-joint is free to move along the drive shaft as well as within the transmission's output shaft. Some small amount of unplanned wear will take place within the "square" of the u-joint as well as on the driveshaft itself. I do not know the hardness of the shaft or the u-joint, so cannot predict whether or not the wear would be significant. This fretting, will, however be a source of metal particulate contamination for the bronze bushing. In so far as it will not embed as it would in Babbitt, there could be an increase in wear of the bronze bushing.
How did I do?
Roll pin like that idea
Took one appart had brass round stock in driveline hole and the ujoint was redrilled
I can't believe that we are debating this issue. Let's see if someone will step up and flat out claim that nobody should be using the pin...
Hal read the post from T Rogers and I think you can comprehend what I was talking about.
Jeez! Nobody said you ought to leave it out! I'd put the damned thing in there if it'd fit! IT WONT GO! I'd never leave it out if it had the original Hyatt bearing and thrust bearing. But I dont.
As for fretting, what keeps the front half of the u joint from fretting in the rear of the transmission shaft? Ain't no pin in there.
Damn. Sorry I asked. I'll let you guys know if it fails.
This business of using roll pins in place of solid headed pins is not good practice. They were solid headed pins for a reason. When roll pins become fatigued, they can lose tension and fall out. As a u-joint develops some movement on a driveshaft, this is one of those places that can happen. I have personally experienced this driving someone else's T with a recently rebuilt engine and transmission. The rebuilder used roll pins in place of the original solid pins on the clutch release forks inside the hogshead. The pins worked out and you can imagine what happened as a result of that. Not a fun day.
If this were to happen with a driveshaft, it would start working off-center and not have a way to fall out. Once off-center, centrifugal force would likely throw it while it gradually cuts away at your driveshaft tube from the inside.
I don't use a roll pin for anything and would rather use a bolt or even a pounded in bent over nail. A roll pin is a straw with less than 50% material and they shear right off with little force. Yes they pound in easy and conform but will break right off. I would not use a roll pin on even a lawn chair.
Put a roll pin in your vice and cut it in half with a hack-saw then do the same with a bolt and see the difference.
I'm rebuilding a Jumbo Planator and there is no hole in the driveshaft for the u-joint pin. The shaft is an old unit. How would you set that up. Looks like it would still need a pin.
Aside from rear end gear alignment issues, there is undue wear on the u-joint, (UJ for short). The UJ operates best when the center of its hinge point sits at the very center of the torque tube ball. Allowing it to float will cause some level of binding at either extreme which will accelerate UJ wear.
In all honesty, if the UJ can't slide back far enough to get the pin in, then it's too far forward to not bind by some degree. Maybe that degree of binding is really small and may never be problem. I don't know. Is it also possible that it pushes the UJ far enough ahead to bottom out on the transmission output shaft? Not trying to pick on you here or to make this more difficult, just looking at the possibilities of future trouble. Hoping you come to a workable conclusion.
Well just went looked at my kast rebiult rearend it been pinned
Must know i was coming all i had to do was pull one cap and peek inside
After all these years, money or other issues, I don't have the proper facing tool for that bushing myself. There. I said it.
I have replaced that bushing with the nice brass ones several times. A few? Have gone in and fit perfectly the first try. (Whew!) One, years ago, turned out, the outer edge of the UJ face was slightly too large, and after fighting with it for awhile, I drove it back out and cut it down in size a bit. Worked fine the second time.
Bad advice department ahead.
Now. One COULD consider grinding the rear face of the U-joint enough to fit the pin? (you would have to get it perfectly smooth, or any roughness would wear the bushing back and cause similar problems with the gears as no pin does) But I have NEVER done that. I have had two that required facing the bushing, and after carefully measuring the amount needed, drove the new bushing out. Then carefully faced it by hand, and reinstalled.
It could work fine? But I REALLY would not want to recommend doing so. It would result in a (wrong) fit that likely would have someone cussing you up a blue streak some day. It would likely be better than running without the pin.
I don't understand why if you have two ways to lock something as crucial as pinion depth and ultimately the health of your rear diff, you would choose to skip pinning it because it was hard and maybe a PITA. As much as i love my FP pinion setup, its just a split shaft collar that you tighten that holds it all in place. Even in the instructions John includes, he says to install the pin. Just like installing a deadbolt on my front door in addition to the lock the door originally came with, i feel better having both.
Some of you need to re-read some of my posts in this thread before making your judgmental comments. As the driveshaft is now, its pin hole doesn't line up with the hole in the torque tube. The drive shaft is too far back. To face the bushing enough to make the UJ hole line up, would put the UJ too far rearward and could bind like Jerry says, but not for the reason he thinks. He thinks the UJ is too far forward. On the contrary, it would be too far back if I faced the bushing or the rear of the UJ enough to align the pin holes. The bushing was faced when I rebuilt this rear end several years ago. So I think the UJ is in the right place when it's against the bushing. Even if the UJ and driveshaft pin holes were aligned, I don't think i could get the pin through the threaded hole in the torque tube. The driveshaft is too far aft. I'm installing a new carrier and ring gear and pinion. I'm reusing most everything else. I have the ring gear against the carrier with no shims between. Many believe shims here are a no no and could be the cause of my broken bolt head and resulting carrier disintegration that caused me to go back inside this thing. So, not wanting to make that mistake again, the ring gear is directly against the carrier. The carrier is also centered in the housing. There is one .015 shim on either side. Knowing what I know now, maybe I would have put them both on the ring gear side moving the carrier off center, but I didn't. So, in order to have the gear tooth faces aligned and have proper backlash, the driveshaft is where it is. To get it to move forward enough to get the pin through the torque tube hole, much less get it to align with the hole in the UJ (which is already toward the rear of the hole in the torque tube, although not so far the pin couldn't be installed), would require either shimming the ring gear away from the carrier or moving the carrier off center in the housing. Those are the only two ways I know to get the driveshaft forward. For all I know, the hole in the driveshaft is located incorrectly, but I got it to fit first time, but remember, the hole was getting close to the edge of the threaded hole in the torque tube that time, too. Just not THIS far.
I hope I have explained this where you can picture what's going on. Some wont bother to read and comprehend it, preferring instead to question my prudence or start new threads making light of it. If that's what floats your boat, you go right ahead.
I want to clarify one other thing here. I AM USING THE FP MODERN PINION BEARING. This is NOT an original set up.
There has been a lot of good discussion above on what could happen if leaving out the pin on an original set up, and I agree with most everything said on that subject. Unfortunately, I think this has clouded the waters on what is going on in my particular case.
So, all the discussion of gear tooth undercutting and wearing driveshaft nuts half away do NOT apply in this case.
This reminds me of a recent spark plug thread
It's your T so do as you wish, others have stated opinion, and the builder of the Fun Project modern pinion bearing says this and this is also in the bearing install instructions provided with the modern bearing.
By John F. Regan on Sunday, May 20, 2012 - 03:19 pm:
As the maker of one of the modern pinion conversions I have to respectfully disagree that it is OK to leave out the u-joint pin. The u-joint is not supposed to slide freely forward and backward on the drive shaft since if it moves to one extreme and there is a sudden drop of the rear end into a hole or other large bump the joint can be caught in a bind since it may not be centered on the pivot center of the large ball housing as it is designed to be. It will then have to slide to its centered position very quickly and thus I can envision it literally "squirting" into position with some force. The pin is placed so that the joint pivot knuckle is centered at the pivot center of the housing ball so both can move together without binding.
Have placed many Fun Project bearings, and always use the knuckle pin in the universal to lock it to the drive shaft.
Makes for easy install of that u-joint into the engine as the u-joint is fixed.
And rear ends I have done, that u-joint is a rather tight fit in circumference within the mouth of the ball housing of the torque tube, you can't place it twisted or it will bind. So, to me that's important reason to pin the u-joint, so it cannot shift and get stuck in the torque tube.
U-Joint engagement, if it can float away, would make it more difficult to an already tough job one-person
Mouth of bell on the torque tube is tight fit for u-joint to slide into, if left to float, it could ride forward and impinge. Mr. Murphy's law #31, "if a thing can slip into the wrong spot, it will"
Hal,I remember having trouble with the pin on my assemblys but I finally got them in there.
As for running ,not running with a pin,
My theory on something like this is Ford built 15 million T's with pins in the driveshaft.
Who am I to decide,they wasted 10 cent's on a pin?
Re-read your full issues completely, and understand. Sometimes dimensions of final parts determine action.
Back in 2012 had similar issue, after assembly of the torque tube to rear axle, the u-joint hole in the new drive shaft was near the edge of the threaded access hole in the torque tube yoke casting, and the u-joint hole was above that, so couldn't fit the knuckle pin.
What I had to resort to was to remove metal off the face of the rear boss of that repro u-joint, to allow the joint to slip down on the drive shaft enough to install the pin.
Had already faced reamed the heck off the brass bushing, as recommended by Fun Projects, cut down to barely any grease groove in the stock bushing. But Prussian Blue on the end of the u-joint showed it still contacting the cut down brass bushing.
Causes: Repro drive shaft, wrong pin hole location, Repro U-Joint, rear boss thicker than Ford original, knuckle pin hole placement slightly off dimension too. And both were a tad too thick on square ends, had to draw file each to allow fit into the female counterparts.
Whole story is below:
I'm thinking that Dan's experience with an improperly located pin hole in the drive shaft is what you're up against as well. If that's the case, moving the UJ back to meet the pin hole would be the wrong thing to do, as you have stated. Sounds like you couldn't, even if you wanted to, since I believe I read that the pin wouldn't even align with the access holes any longer.
Since you don't want redo everything, consider, if possible, re-drilling the pin hole, using the UJ as a guide. This may create an oblong pin hole in the shaft, but that really won't matter. The re-drilled portion of the hole, will engage with the pin to prevent the shaft from drifting backwards and the Timken bearing in the FP kit will prevent it from moving forward. I would not recommend drilling a new hole at 90 degrees to the existing one however.
Jerry, that might work. However, in my experience, trying to drill half a hole doesn't work so well. Actually, it would be more like 1/4 of a hole. The misalignment is about 1/16". And I dont want the chips all in there. It is together and I just got back inside from taking it up the road and back and re-torquing the axle nuts.
I did pull the upper plug in the torque tube where the pin goes. After wiping away enough grease to find the hole, I pried the UJ fore and aft the extent of its movement. It was about 1/8". It essentially moves aft until the UJ hits the bushing face, and moves forward until it bottoms in the transmission shaft. At either extreme, the pin hole is just inside the edge of the hole in the torque tube. Almost tangent, but not quite. It truly could move very little. I really don't feel like it is a problem.
To those who have been sincerely concerned and tried to help. I do appreciate it. Those of you who chose to ridicule and lampoon, glad I could be the butt of your juvenile jokes.
Most likely it will be o.k. I didn't realize you had it in the car already.
I think that initially, folks just didn't understand the situation you were in.
If the pin was not needed don't you think Henry would have eliminated it to save a buck or two, it was there when we rebuilt the rear axle and its there now, if its worked for 100 years don't mess with it now Cheers Colin
Don't be an @$$hole, Tim. You're getting bad as Arnold.
Is this Arnold?