I'm a little concerned about doing this, but I figured if I listed my concerns, Maybe someone (or somemany) will ease my Lizard brain.
1. The spiral design scares me a little because of what debris may be lurking inside those grooves. I have noticed that some of the spiral grooves are wider than others. Wide enough that some nasty crud could come out and contaminate new grease.
2. I have read that .480" to .500" is a good usable bearing, but what about other concerns? Does it matter if the cage is a little loose? Does it matter if the end plates have wear grooves in them?
I've searched, but have only found the bearing measurement for using an original bearing........
The assumption when reusing the originals is that you are going to clean them completely so there is nothing to come out. That means also inspection that no metal chips are stuck in tight places.
Layden is right. The spiral design is a tried and true design. If a used bearing is cleaned up, checked out for excessive wear and installed properly they will last a long time.
The cage's can be rebradded to tighten them up but for me I try to use the one's that are tight to begin with.
The inside sleeves usually don't wear as much as the outer and I would replace those with new one's.
And again as anything you reuse you will use them if they are good to begin with and you clean them up.
If your rollers are measuring .480" you need to replace them. A couple thou wear is OK, but not that much.
I am going to put a couple of them in my ultra sonic cleaner and hopefully it will get the inside of the spirals super clean.
Well, I Don't have an ultra sonic cleaner lol so I think I'm going to clean the 4 bearings I have as well as possible. Then I will dismantle the worst one and see if there is anything undesirable left behind on the inside.
The Inside, where no Normal human being could possibly Know whether they got it clean or not!(also where many say the bearing "absorbs" debris and particulate)
Now, having said that, I noticed that two of the bearings have Very tight cages. The other two I can Just get a slight movement if I hold the bearing in both hands and twist the ends in opposite directions. Nothing that I would call loose by any means, just to say it is Not absolutely Tight.
In the axle book Glen says the rollers should be .498" to .500". The cages should be tight. If you peen the ends of the rods and they're still loose, get better ones.
More important than diameter is the surface. There should be no evidence of spalling or metal fatigue. I think you could safely use good bearings with a 0.495" diameter. The Model T rear axle is not a precision assembly and is very forgiving. Just be sure you have replaced the Babbitt thrust washers with bronze.
The bigger, the better! I would never consider .480!
I've gone thru' a bunch that I've run across and right or wrong, I keep any that I find that mic up .495 or better. Also, the surface of the rollers must be smooth and not pitted, and the cages must be tight.
I'm sure there are those that know much more about this than me, but my own personal opinion, mostly formulated by many years of reading on this great forum, is that peening to tighten loose cages is usually not very successful. Maybe that's because some are better at the "peening" than others, but again, my opinion, it's just not that hard to find used Hyatt rear axle roller bearings in good shape. I think that this is because every rear end had four of them,.....two inners and two outers, and even a rear end with badly worn outers will usually have a pair of inner bearings that are still in good shape. That it because the outers carry the weight of the car, and the inners wear very little because they carry no weight at all.
All that to say (again) I would rather use good used Hyatts than the current style "repop" solid roller bearings, partly because they're easy to find, and importantly (to me anyway) the originals have a very minute ability to flex due to their "wound" construction, whereas the new solid rollers will not flex at all. My thoughts as to why this is important it this,.....think about it,.....the rear axle bearing "races" are not a machined bearing race that is perfectly round and symmetrical. They are a sleeve that is formed of sheet metal and not necessarily perfectly round. And that's my "theory" as to the importance of the wound Hyatt rollers being able to flex to a slight degree and are more likely to make "line contact" with the sleeve, whereas the solid roller just might be forced to make only "point contact".
Sheesh! Did not mean to go on and on like this, but that's my feeling about rear axle bearings,.....YMMV,......harold
Okay, while I'm "expounding" here,.....one more thing that kinda' "bugs" me:
Original Hyatt rear axle roller bearings do not have "spiral grease grooves" like some folks think, again, in my opinion! Yes, they have the spiral grooves, but that is just because they are wound that way when they are made. However, I do believe that there is some benefit from the fact that those grooves do have a slight tendency to help "distribute" the grease a bit more evenly than a solid roller would. This is why the direction of the spiral alternates back and forth between adjacent rollers. Again, all my OPINION, not verified by anything or anybody, and I am now through "expounding",....honest,......harold
Used bearings work fine for me. There is no alternative!
Regarding loose cages...I don't bother peening, but instead I braze the pin to the circular header... lightly. I have restored many Hyatts this way, particularly smaller ones used in transmissions.
If we all followed the ".498 - .500" theory in the book, we'd all have a pile of scrap bearings and very few good ones. The rear axle bearings are slow moving units that will roll forever if properly greased. A .495" bearing will work fine, but that is as low as I go, only because bearings .495 and above are plentiful.
My coupe has been in our family since 1948. I have the maintenance log and my Uncle who was the care-taker of it since 1966 is still here as a resource. In any event, the car still has the same axle bearings in it that it had in 1948 and based on the log history and touring that has been done with it, the bearings have about 100,000 miles have them. I measured them in 2004 and they were .492" and .493". The axles are still good and smooth. In discussion with my Uncle he told me that the key is keeping them greased and using good NOS sleeves and changing them when they start to show wear. He said the bearings and axles will roll forever so long as everything is lubricated. I put the worn bearings back in and it's still rolling along.
All good responses and I really like the suggestion by John about brazing the cages. Starting to get a much clearer picture of how to judge a good used bearing!
In case someone hasn't mentioned it already, there is no reason to disassemble your bearings to clean them. Frankly, this will ruin them as it will be very hard to reassemble them. Just wash them in your favorite solvent, (mine is gasoline), blow them out, let them dry and you'll be fine. Don't over think it.
It's funny but only Jim Lyons has mentioned sleeves. Sleeves are now available from Langs, that are duplicates of the originals.
I clean usable rear axle bearings in an industrial quality heated ultrasonic cleaner at 190 degrees F in a commercial "hot tank" solution for a forty-five minute cycle then then blow 80psi compressed air thru the "hollow" of each individual roller... And I usually have to repeat this process THREE TO FIVE TIMES before crud and grit are not coming out of the inside of the rollers anymore...
I think the top two causes of outer roller bearing/sleeve failures on "rebuilt" rear axles are: "not clean enough" and "poor fit"...
I have also found that MOST OF THE TIME when the cage of a roller bearing is loose, the rollers are slightly tapered. If you "tighten" the cage and re-use that bearing, it will loosen up again right away AND it will track slightly left or right and maybe cause some other wear issues.
If I find good original used bearings with ALL rollers measuring .496" or better, AND they have .001" or less taper on EACH roller, AND they have tight cages, Then I consider them re-usable.
I also tell my customers that Model T rear axle outer bearings need to be serviced the same as a trailer bearing... Once per year: remove the wheel, seal, & bearing. Clean the bearing, wipe the sleeve and axle shaft as clean as you can with clean rags, inspect the axle and sleeve. Clean inspect, and re-measure the bearing, re-grease the bearing and re-install. This takes most people about two hours from start to finish and can save you hundreds of dollars and days of work. The sleeve and bearing will generally begin to wear before the axle shaft and if you catch a potential "wear issue" in time you can avoid the possibility of ever having to replace an axle shaft.
I have used a shim behind the sleeve to tighten up the clearance between the rollers and the axle. This is in a car I restored in 1992 and it is still running strong.
Good point about the shim behind the sleeve. Don't seem to be many people taking advantage of that factor. If you find your rollers are 480 thou or so, try a 10 thousandths shim between the sleeve and the housing.
Can the cage be welded ??
Lorenzo, just my opinion, but I would be a little scared to weld the cage. Because the spiral rollers flex a bit, I reckon during driving over bumpy conditions, they impinge on the cage pins and load them up to some degree. This loading might be larger than we imagine, especially when hitting large bumps, potholes, etc. That, in effect, can be a shock loading on the cage pins, which transmits throughout the cage, and the weld, which would be a weak spot during shock loading due to the probably imperfect material properties in the heat affected zone of the weld. I would be worried the cage/pins would crack at the weld.
If your rollers are .480 chances are they're also tapered and pitted. This would be a severely worn bearing, i.e. junk.
Adam, Great informative post and Exactly what I was concerned about. Just looking at the design I knew the potential problem would be whether or not one was able to get everything out of the inside rollers.
I've read a ton on this subject and the biggest difference I see between the OE bearings and the ones you can buy now is that the remade new ones now have 1 less roller.
That does bother me, and it's the Only reason I'm even pursuing cleaning and running the original bearings. IF the new solid bearings (solid meaning, Not wound) had the same # of roller or More, I wouldn't hesitate to put them in.
Now here is my other concern with the bearings I have. The "slightly loose" ones are from the outside and the ones in the pics are from the inside by the carrier. These are tight, and measure .499 - .495, but look at the grooves worn into the cage sides.
When my bro first started to clean these up there was a Lot of metal debris coming out of them. Kind of scary....
Lorenzo and Richard,
*Welding* is too much for such a small object... perhaps TIG with a careful hand. Minimize the heat and keep the area small. That is why I suggest braze as the heat is low and small area and quick. It is also easily controlled.
Robert, the lower number of rolls isn't the main problem with the repro bearings - it's the fact that the rollers are solid. The old Hyatt rollers are made out of a tightly wound spring for a reason - to be flexible and forgiving so the edge pressure won't be too high at the ends of the rolls etc.
The most trouble has been reported when using repro solid bearings in the drive shaft - a broken pinion bearing / drive shaft assembly is a safety risk on a T - you may loose the service brake, so the replacement modern Fun Projects pinion bearing is highly recommended if a good original driveshaft Hyatt can't be found (and they're much harder to find than good rear axle Hyatts.)
I went with the FP pinion bearing, was a no brainer for sure.
Dang, if the solid cased roller bearings that replace the entire sleeve and all weren't 200.00 per side I think I would have just gone that route and forgot about it Forever! lol
So if there is no reason for me to be concerned about the wear grooves in the ends of the cages, maybe I will take a trip to my friends machine shop and use his sonic cleaner for a few hrs and see how clean these come.