MTFCA Forum

I an glad that I decided to rebuild this rear axle instead of waiting. There was not much endplay ,but you can see the edges flaking off. Also the oil grooves are filling with broken down babbit.

Babbit makes a good bearing surface,none of the pins were worn or loose.

I disassembled two rear ends this month to try and make one good one. Only one of the Babbitt bearings made it out in a single piece. The rest were crumbs. Some Babbitt flakes embedded themselves in gear teeth, which took a lot of wire brushing to remove without damaging anything. The best news was that I have 4 good hyatts to reuse.

Mark this one has 4 good Hyatts and a good ring and pinion also. Sounds like you will come up with a good rear end.

My first model T had the Babbits in the bottom of the housing. The pieces were smooth Kidney shaped. It had been driven that way a lot and the gears were shot.

John

Just a niggling point. The lead-alloy differential thrust washers are not exactly a “Babbitt” alloy as rod bearings and mains are. The washers were die cast from what is generically referred to as “pot metal” a substance which has no specific recipe, being largely composed of zinc plus lead, tin, bismuth, antimony and other soft metals in proportions which were found to give optimal results as a “precision casting”.

50 years ago, “babbitt” washers could be found perfectly sound, and capable of giving service, which ofcourse they provided when Model Ts were new. As the material ages, however, it has shown itself to have the attribute of “self destruction”. Pot metals are porous castings, and chemical interactions of the alloyed elements seem to cause items cast from it to simply rot away, becoming brittle, fragile and generally unsound with advancing years. The rate of deterioration varies with environmental factors.

Spontaneous breakdown of the washers has become especially apparent the past fifteen years or so, and makes it imperative they should be changed out even when an axle appears to be sound, “untouched” and functioning well before the inevitable “grey death” causes extensive damage. Safety is also a large factor in assuring a Model T rear axle is fully roadworthy.

What Rich B said is a very good description of the "Babbitt" washers and their place as an ancient "used to be a good idea". The metals mix varied from day to day, and therefore the survival ability also varies a lot. When I was getting started in this hobby a bit over fifty years ago, most hobbyists believed the original washers should be used if they were in good condition. Part of this belief was in the false assumption that if it still looked good, it had not been exposed to damaging corrosion and should therefore be safe for another fifty or hundred years. However as Rich B said, their makeup makes them susceptible to a "self disintegration" . I was fortunate to have been given good advice very early, followed by an experience that proved to me that these original washers should NEVER be used. Unfortunately, too many people did not take the message, and continued to use the originals. So even if a car has been restored, even if very nice, years ago? The rear end really does need to be opened up and checked. And be aware! You cannot go by a quick look at the color of the edge of the washer! Because of the different mixes of metals and chemicals, once in awhile, the used to be silvery colored "Babbitt" can sometimes turn to a brassy color. Several people on this forum, including I, have found ones like that!

Sometimes you find them intact.

Usually you don't.

Some vendors who sell thrust washers say they are brass and some say bronze. Are there two or more different washers or are they the same with different descriptions?

My point is that I need to order washers and I don't know if I should get brass or bronze.

Brass is for decorative purposes, bronce are also for bearing purposes.

...I don't know if I should get brass or bronze.

They're all bronze. I don't know why some of the catalogues call them brass. They do the same with bronze bushings.

I’m sure to be corrected by experts who know better, but I’ll offer what I gleaned from an association with a production engineer who established a soft metal foundry here 30 years ago. Interestingly, he named his enterprise “Blackfoot Brass”.

According to him, most alloy proportions may be specific for an application, but technically, all alloys combining copper with tin, zinc, antimony and any number of other possible amendments are “bronze”. Recycling scrap materials by sorting them as “red brass”, “yellow brass” or “naval brass” produces variable unsatisfactory results because the specifics of the alloys are unknown.

Bushing materials are generally referred to as “bronze”, perhaps to distinguish them from other alloys better suited for decorative purposes. Bushing stock often contains graphite, lead, and other amendments designed to provide lubrication and/or better wear characteristics.

For the Model T rear axle, since pot metal performed adequately through many thousands of miles, I sincerely doubt it matters a whit whether replacement washers are made from decorative brass stock or a perhaps more appropriate bearing bronze material. The important thing is that unlike pot metal they won’t spontaneously disintegrate any time soon.

I pulled an original differential apart a few years ago, only to discover both sides were in perfect condition! My thought on this is when the car was restored in the late 40's, they must have been replaced. This is a 1913 runabout I own.

That’s most likely, Larry. Interestingly, the 1915 parts list specified bronze thrust washers, which makes it a point of interest as to when lead alloy washers were introduced into production.

For many years, my dad had a stack of NOS alloy thrust washers on the shelf but I believe he threw them out ten or twenty years ago. I'll have to ask him.

I'm sure others probably have some NOS specimens in their parts collections.

Ford Methods and The Ford Shops, (1914) photo from page on rear axle assemblies, the caption calls the thrust washers as Babbitt.



Have pulled many used babbitt thrust washers from rear axles, sometimes intact.

Did a garage test one day, took a new repro bronze thrust and an intact old Ford babbitt thrust washer and dropped them from waist height onto the concrete floor. The bronze washer bounced and bounced making a nice ringing sound........that babbitt.....it just smacked on the floor, with a thud and clacks, as pieces flew off it, so brittle.

No way a babbitt thrust washer should stay in any T axle running around today

I recently joined this fraternity when I disassembled the rear on my ‘13 Runabout. This washer was intact, the other was in crumbs at the bottom of the differential.

Anyone that has completed a differential tear down and rebuild should get a 'Rear Pumpkin Fixed' certificate of completion.

...and take pride to mark your successful completion of the rebuild, with a tag to note the date and let the next owner know someone has been in there and made it safe from crumbling babbitt.

The gentleman that started the restoration of my 15 Runabout has gone west so I have no way
of knowing if I have babbit or Bronze washers. My rear end is a ruckstell. Is it possible to see the washer with the shifter removed?
I would guess that the rear brakes that I have would allow me to stop if the wheel axle didn't come out?

Is there anyone that can make these for me instead of having to one off buy the tag material and the punches.

DanTreace wrote: ↑

Thu Jan 09, 2020 9:46 am

...and take pride to mark your successful completion of the rebuild, with a tag to note the date and let the next owner know someone has been in there and made it safe from crumbling babbitt.
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