MTFCA Forum

the statement that later T's came with bronzé thrush washer in the difference? I thought they were all babbitt.

Differential

I have parted out a lot of 26-7 rear ends & not seen anything other than Babbit.

This has been brought up before. For a short time around 1915 they were bronze. Here’s an earlier post about it. There are others also. https://mtfca.com/phpBB3/viewtopic.php?t=33037

viewtopic.php?t=20887
Here’s another

Interestingly, they never were “babbitt” as we understand alloys commonly used for engine bearings, but a lead/zinc alloy developed for die casting commonly referred to as “pot metal”. The thrust washers performed adequately in the era, and for many years afterwards. At a certain point, it seems they self destruct. Whether it’s intrinsic with the alloy, or the result of years of immersion in gear oil, they simply crumble into pieces. Draining the lubricant from a differential often reveals evidence of the “grey death” indicating failure of the alloy thrust washers.

Their use from 1915 on was doubtless an economy measure, as the parts could be precision die cast, eliminating the need for machine finishing. I recall seeing “babbitt” thrust washers with clear, crisp “Ford” script in the grease grooves of the parts.

Interestingly, they never were “babbitt” as we understand alloys commonly used for engine bearings, but a lead/zinc alloy developed for die casting commonly referred to as “pot metal”. The thrust washers performed adequately in the era, and for many years afterwards. At a certain point, it seems they self destruct. Whether it’s intrinsic with the alloy, or the result of years of immersion in gear oil, they simply crumble into pieces. Draining the lubricant from a differential often reveals evidence of the “grey death” indicating failure of the alloy thrust washers.

Their use from 1915 on was doubtless an economy measure, as the parts could be precision die cast, eliminating the need for machine finishing. I recall seeing “babbitt” thrust washers with clear, crisp “Ford” script in the grease grooves of the parts.

I have a lot of old babbit from old oil field engines and various poured bearings on wooden oil rigs. It does not deteriorate over time, even when exposed to weather or salted earth for decades. The "pot Metal", on the other hand, is a different material. It's more brittle, and it often decays over time, even when used for radio parts, ornamental items, and other indoor-kept items. I've seen it swell, crack, crumble, and even show a sort of surface blistering. Bearing babbit, on the other hand behaves like lead bullets or fishing weights. It's very stable over decades even in harsh environments, and it can be easily remelted and recast. I would not use old "found" babbit for engine bearings, since the original makeup of the babbit alloy might not be suitable, or it may have been overheated or otherwise abused to the point that its properties have been altered to some degree or other.

My father had a stack of NOS babbitt thrust bearings that he picked up from a Ford dealership in southern Minnesota around 1950.

Over time, they got scuzzy just sitting on the shelf in my grandparents' basement and, later, in my father's garage. He eventually tossed them.

The "pot metal" differs from true babbit metal. It will decay over time on the shelf or in service. True babbit will not.

To the OP's question. It was actually the early cars that had bronze thrust washers sandwiched between two steel washers in the differential. From early 1909 to sometime in 1914 the thrust washers were bronze before being changed over to babbit.

From the Encyclopedia pages 574-577 " A bronze thrust washer (2528)(30) and two steel washers (2529)(31) were used on each side to locate the differential assembly in the axle housing."

From page 584 regarding the late 1914 differential "According to the Parts Lists the side thrust bearings (sic) were changed from bronze to babbit about this time as well."

Hope this helps.

Ford may have used true babbit for thrust washers at some point. But they used the "pot metal" too. "Babbit" is a family of alloys. Pot metal, likewise. Pot metal is generally less malleable than true babbit.