Putting rear axle together. Hyatt bearing on one side slides right in; bearing on other side needed some light tapping with block of wood/hammer. Outer end of bearing turns with axle. Is bearing too tight against axle and/or sleeve?
Sounds like it. Is it too tight because the axle shaft is not centered in the housing (Bent housing)? Or because the sleeve is too thick?
The axle housing (right) is new to me as it came with Ruckstell kit from Chaffin's. I had used the sleeve and bearing before; they were a loose fit, as should be, in the old housing. Bearing slides easily onto axle without sleeve in place. So -- probably sleeve is now too thick.
Check bearing sleeve to see if it is in correct position and not partially lifted. This will cause bearing to be to tight.
Look to see that the round hole in the sleeve matches the bump in the axle housing.
There is a variation in the axle housings, so sometimes you have to mix and match parts to achieve the correct bearing play without binding. Sleeves are made with different thicknesses + sometimes you can find Hyatts with just a little more wear without pitting on the rollers or a loose cage.
I have had good luck on thin bushing on more modern transmissions (Chrysler Torqueflite) using a brake hone and some light oil to hone the bushing to a slightly larger size. Use a light touch and check the fit often to make sure you don't overdo it.
I had a similar very snug Hyatt bearing in a repro sleeve that worked out fine. I had to tap it in, but it did not bind and finally seated. That rearend went to Royce Peterson who put 3000 trouble free miles on it before he sold that car to Charlie Jenkins, who in turn sold it to Constantine, who drove it from Melburn to Moscow. BTW, that rearend also has the non-grooved repro inner position bearings and repro axles. Moral of the story....you can't kill one of these rearends.
Model T axle housings are notorious for getting bent. I suggest you find a T guy who can straighten BOTH your housings. I just sent out an early Ruckstell housing to get straightened, and it was out 1/4". Do your homework.
It is not unusual that even the best quality repro sleeves are not perfectly round.
I made a hardened fixture to press new sleeves into that is precisely made to the FORD blueprint for the rear axle housings in which the sleeve fits. The fixture allows me to make slight corrections to these sleeves on my honing machine
When installing any particular repro sleeve into the fixture and measuring all over the inside of the sleeve with a dial bore gauge, I generally find there is a certain portion of the sleeve that is about .003" undersize (which is the area of the interference fit). I have developed a three step honing process which opens up the tight clearance to a slip fit, brings the sleeve closer into being round, and provides a proper surface finish. New, repro sleeves generally have variances in their diameter of as much as .008" and a particular area that is very often .002" to .004" too tight. When I am done "blueprinting" a sleeve, the smallest clearance in the sleeve will be at, or a couple tenths of a thousandth larger than the total of the axle shaft and rollers. And the largest diameter is usually around .002 oversize of that. (which is likely as good or better than original FORD parts would have been, but I never had any excellent originals to check)
I should probably add that there are one or two people on the forum that might chime in here and say that finishing a part like this and ending up with a .002" variance in internal dimensions is hack machining or cobbling and that the part should be absolutely perfect. All I have to say to that is: If you are willing to set up fixtures on a lathe for each sleeve, and adjust for center based on all the little irregularities in the new sleeve, and then internal grind the inside to prefect roundness and correct surface finish, wind up with a perfectly round bore, and then GET SOMEONE TO PAY FOR YOUR MACHINE TIME, you are welcome to do it... And by the way, you will very likely end up with a product where the inside is not perpendicular to the outside, and that is also .002" to .006" oversize!
My procedure is done on an industrial honing machine that has an action that more or less "splits differences" and straightens out internal bores. On a bore like this, if you stop honing at a couple tenths of a thousandth over your target, you have not removed enough material to make the bore perfectly round or perfectly straight, but the bore you do have now it is many times better than the original part, and now will be quite usable with very good longevity and increased life.
The roller bearing should slip in and out of the sleeve with the axle in place. You should be able to easily push the sleeve in with two fingers. ***If you can't then something is wrong that needs to be fixed.***
The repro bearings that are solid with six rollers also seem to work quite well when the sleeve is properly blueprinted. When the sleeve has a little high spot where there is an "interference fit"; that high spot will grab each roller and the cage of the roller is no longer doing its job of merely keeping the rollers from running into each other. The cage now has to drag the roller past a grabby high spot and it was not designed for that. The pins on the ends of the rollers then begin to wear into the cage more rapidly, the holes in the end of the cage increase slightly in diameter which now allows the cage edges to contact the sleeve and the axle shaft which frees up small particles of metal to mix with the grease and slowly (or quickly) start wearing away at the sleeve, bearing, and axle shaft which prompts posts on the Model T Forum about plain repro bearings being no good...
Adam: I'm impressed! I wish I could drive over to see your operation. BTW, I know of three people here in So.Cal. that have fixtures for straigntening the rear axle housings. It amazes me how they get bent, but they do. Are you using the new sleeves that Steve Coniff developed several years ago, and Langs now sells, or the RBC sleeves?
The same thing happened to me when I rebuilt the Ruckstell this past spring. The bearings were the old, original type; sleeves NOS that I bought from Marty Pendriss; the Ruckstell, all new parts from Chaffin's. The issue was the fact that things were now tight in the middle causing things to be a tight fit on the outside. Marty drove over to see the problem because he couldn't imagine things fitting so tightly. Both he and I gradually worked one side, then the other, one side, then the other and got the bearings and sleeves in.
Nice write-up! Good information and well written.
Drive carefully, and enjoy, W2
Larry, People mention they want to see my operation quite often and I always tell them there really isn't much to see. I work in the 400 square foot heated & air conditioned end of my 900 square foot garage. There is a big lathe, small manual mill, surface grinder, big blast cabinet, parts washer, industrial hone, HCCT, small press, cabinets full of jigs & tooling, babbitting equipment, and that's about it. When the shop is clean and everything is in its place, there is still just enough room to bring a Model T in and work on it. There is 2' along each side and 3' in the front & back! When I built the garage I designed it just for working on T's, so everything fits real nice. I have someone I hire to bore & hone cylinders & grind cranks because it doesn't pay to purchase, house, & maintain those machines until I'm doing like an engine a week, and I really don't want to do anywhere near that many. I would far rather do a few very high quality motors per year than simply "crank out" a bunch of "factory work"...
Great write-up, Adam. I've always accepted the conventional wisdom that the modern, solid roller bearings were good only for limited use.
Do I take from what you have written that the modern bearings are fully usable providing the other work is also done ?
This brings up another question: Are the original Hyatt bearings purposely designed to tolerate inaccuracies in the sleeves ? I'm always impressed with designs that are especially tolerant of imperfections in manufacturing or assembly.
Dick, I thought the same thing for several years, but then I found a bearing company in the U.S. that manufactures and sells these style bearings & sleeves in all sorts of sizes and shapes for all sorts of machinery. Their T sized bearings & sleeves are several times the price of the ones supplied by the T parts vendors and their sleeves have no dimple or hole in them, so they are not the sort of parts us T hobbyists would be interested in, but I did have a discussion with one of their engineers about hardness, etc and their product compares with the bearings from the major T parts vendors.
At this point, I have a theory that the modern bearings are just fine and there are other issues present in the average rear axle rebuild that causes what appears to be "less than satisfactory life" of the repro roller bearings. I say that this is a theory because I feel that I have to take a scientific approach to this sort of thing and I have not been blueprinting these sleeves long enough, nor have I put them in enough rear axle rebuilds, nor have they been driven enough miles yet to prove the theory. But I am confident I'm on the right track.
-The number one offense is that the bearings should easily slip in and out of where they are supposed to be. Any interference or tight fit needs to be fixed. The small irregularities in the sleeve seem to have a great reduction on bearing life. The number two offense is something that there is not a good way to fix; All the repro axle shafts that are available (that I know of at this time) are too soft. A had some original T axle shafts tested a few years ago and the original shafts were about a 50RC hardness, and all the repro shafts available were about 25RC hardness. I was going to make a couple hundred shafts to the Ford print a couple years ago, but they would have been around $300 each retail and I realized nobody would be likely to buy them when there was ANYTHING ELSE with a lower price available, so I put the project away in the filing cabinet.
Good original Ford shafts are scarce, at least around here. I haven't seen one inside of the last four years. There always seems to be something wrong with them someplace if you know what to look for.
So, if I don't have a pair of good used Ford axle shafts for a rebuild job, then I'm pretty much forced to use a repro axle shaft that is too soft because there is nothing better available. Blueprinting the sleeve, and using a new bearing gets everything really nice and straight and round and so far seems to do a pretty good job of extending the life of the repro axle shafts as well.
As for "original" Hyatt bearings with the grooved rollers... I think that the grooves might have been a cost saving measure in the amount of material that each roller required. I also think that the grooves maybe were beneficial to help circulate the lubricant that was used "back in the day". The rollers were wound out of flat stock which meant a couple things: They used less steel than a solid roller, they already had a hole down the middle and required less machining, a finished bearing weighed less than a solid one, etc. I don't think I buy the idea of the wound rollers being "flexible", although I've never tested one. As thick as the material is and as small as the radius it is formed into; Would 5-7 hundred pounds of weight be enough to make the roller flex? And if they do "flex" then how come they don't work harden and break? It seems to me that if the rollers did flex, we would occasionally find broken rollers and I don't think I've seen one...
I would be interested in any feedback from others.
If you check the inside diameter of the Ford housings you will find that they vary drastically. I have measured 2.200-2.227, that's a 0.027in variation. This is the major source of this problem. Ford's sleeve thickness spec was 0.068-0.071. The new Bradley sleeves measure 0.0705. The old Mark Auto sleeves were 0.067. The old Snyder's sleeves were 0.065. Bradley's sleeves are within the Ford spec but are usually tight. The old Mark Auto and Snyder's sleeves usually fit ok but are no longer available. After you check your housings for not being bent you must mix and match the other parts for the fit you want. You can also hone the ID of the sleeves as Adam suggests to make them round. This will help in making the proper fit. Or you could hone the inside diameter of the Ford Housings.
All very interesting, Adam,
I can offer an answer to one of your unknowns. You asked, "And if they do "flex" then how come they don't work harden and break? It seems to me that if the rollers did flex, we would occasionally find broken rollers and I don't think I've seen one... "
Carbon steel is one of the few metals that has a pretty much infinite fatigue life as long as the stresses are kept low enough. Most metals, aluminum and stainless steel for instance, will eventually break even under the lightest cyclical loading. So as long as the flexing of the rollers is kept below the critical level, you won't ever see any breakage. Wood, incidentally, is an ideal structural material in this respect. Wooden parts can be taken to nearly their breaking point an unlimited number of times with no ill effects. Just keep it dry and keep the termites away.
Here is a good 2010 thread on Hyatts: http://www.mtfca.com/discus/messages/118802/139903.html?1273501621
Dan Treace posted this info from a 1914 book, "Questions and Answers Relating to Modern Automobile Design Construction, Driving, and Repair" by Victor Page:
Obviously the thinking of the time when Hyatts were designed was they should flex. Interestingly enough Hyatt rollers rarely break in the rear axle, but broken rollers in the pinion bearing are rather common, even though there isn't any irregularities in the outer race for the pinion bearing as it is for the axle bearings..
The culprit in the pinion bearing is probably the inner sleeve - they are crack prone when worn out and may start the breakdown process when a fatigue crack appears.
My solution? As good old Hyatts as I can find in the rear axle and a Fun Projects pinion bearing.
Glen, Dick, Roger. All good "food for thought"
Glen, The Ford print I have specifies the sleeve area of the axle housings to be reamed 2.208" to 2.211". I would then have to say that any used housings over or under these dimensions are not to design spec and should be discarded or repaired, or the other parts on that rebuild job should be modified for a correct fit. I agree that a little larger inside diameter in an "off the shelf" product will insure that the average hobbyist meets with better success, but I prefer to have a sleeve a little on the small side because it is easy to make it bigger and rounder but real hard to make it smaller.
Dick, In regards to carbon steel having a pretty much infinite fatigue life; Yes, I believe that, but only if it was very carefully & properly designed, with a life and load capacity far beyond what it would ever see... Otherwise bridges wouldn't fall apart, T engine pan arms, front cross-members, crank-shafts, & axle shafts would never break, etc. At one time, Ford experimented with crankshafts that were 1/8" smaller to save materials. They simply did not hold up in ordinary use. If the T crankshaft was made 1/4" to 3/8" larger, then I bet it would be really really rare to ever hear of one breaking. My guess is that the rear axle roller bearings were designed well over the maximum load they would ever see.
Roger, I can see how the original rollers could have a small degree of flex in the long direction, but what I find hard to believe is that they have much, if any flex in their diameter, which is the largest "fit problem" I see in the average home rebuild project I see people working on (the fit problem where hobbyists use a block of wood & a hammer to drive a roller bearing into the outer axle housings and then a couple years later see something in there badly worn out and say it must be because the repro parts were no good). I wonder if someone has some piece of equipment equivalent to a spring tester with a dial indicator so we could see how much "flex" we get out of a roller at a couple hundred pounds...
The sort of thing I'm talking about is that when everything is finished to the right size & surface finish and all straight and in good alignment, with all new repro parts, you can insert a pair of sleeves in a housing, put an inner bearing on a shaft, put the shaft in the axle housing, and install the outer bearing. The bearings should have easily slipped into place. Next give the axle shaft a spin. Everything should be nice and smooth with no bumps or grabby spots and the shaft slowly glides to a stop... and all without any oil...
With the finished rear axle & drivetrain all assembled, you should be able to turn the u-joint and both rear axles should turn at the same speed without either one stopping or hanging up.
Differential housings can be under a lot of stress particularly with a Ruckstall. A Ruckstall is designed for greater power to the rear wheels, some cars had large metal cleated wheels and or pulled various appliances. Some of the appliances were attached to the differential housings either by chains or welded brackets. A car that was converted for pulling will usually effect the drive train. This can pull, streach and bend various parts. The yoke housing can get pulled an broken, the rear crossmember can be bent, rear engine mounts can be pulled and cracked and the frame can be bent, all this from over stressing the drive train. They were never designed as a tractor. The Ruckstall was a good invention for more power but there was usually additional related costs.