Well the banjo axle which we drug out of a field to put in our '32 decided to blow up about a month or so ago. The parts within the axle were in service for an unknown number of decades. The pinion gear broke several teeth off which is what necessitated the rebuild. Number one son was the one responsible for nearly single-handedly rebuilding the axle. We didn't have a dial-inch-pound-torque wrench prior to this project so we decided to purchase one. We (number one son) did a copious amount of research on the topic of banjo rear axles, specifically: how to rebuild one. What we found was that there seems to be all kinds of conflicting information regarding the procedures and specs for rebuilding one of these dinosouar axles. We gathered as many of the different specifications and procedures as we could dig up and tried to intelligibly choose which spec/procedure to use for the particular task at hand.... Our research included: Magazine articles, period manuals, and untold hundreds of posts scattered across different forums. SPECIFICATIONS: Pinion preload was set at 15.5 in/lbs Carrier preload was done by feel having "heavy drag" when both axle shafts are rotated forward in the same direction at the same speed. Backlash checked out at .008" The gear mesh pattern was checked and looked acceptable: good tooth contact pattern, centered between heel - toe and root - flank. Building this axle is relatively simple and straightforward, but it requires a lot of dis and re assembly to set up. First clean the housing very well, especially where the flanges of the bells meet the flanges of the banjo. Next set up your pinion bearing preload with nothing in the banjo other than the pinion gear assembly. For adjusting carrier bearing preload and backlash: Start out by throwing some gaskets between both bells, (either .008" or .010") and begin experimenting with different gasket thicknesses between the passenger side bell and banjo first in order to properly set your carrier bearing preload. Then, experiment with different gasket thicknesses on the driver side to set your backlash. Note: if you add/remove gaskets on the drivers side, you need to do the EQUAL and OPPOSITE thing to the passenger side. For example: if you add a .006" gasket to the drivers side to get your backlash within spec, then you need to SUBTRACT .006" of gasket from the PASSENGER SIDE. You do this in order to preserve your carrier bearing preload that you already set. The banjo or centersection during pinion preload setup First one nut, then the lock tab thingey, then the jam nut. Make sure to recheck pinion preload AFTER tightening down the jam nut as it MAY cause your preload to increase. We set our pinion preload right about 15.5-16 in/lbs. If you accidentally overshoot your preload specifications, you can undo both nuts, then strike the pinion shaft with a deadblow/brass headed hammer: Tightening the pinion nuts will either require some kind of holding fixture, or, a couple of cheater pipes with a second set of hands: RECHECK your pinion bearing preload after tightening both nuts: Torqueing ring gear bolts: (First spec we found was 60 ft/lbs but that broke a bolt so we used 30 ft/lbs) The carrier bearing races are driven in carefully again with either a soft faced hammer or deadblow hammer: Applying a little grease to the area where the race presses in will ease installation: Axle ratchet strapped to the bench: Keeping track of the gasket adjustments: More Gaskets. I believe the white one is .004" and the green one is .008" Number 1 son: Money shot of the pinion splines: Adjusting the gasket thickness on drivers side to set backlash: Same as above: Measure once cut twice? or is it thrice? Setting up the dial indicator for a reading on backlash: Gently rock the pinion gear back and forth ever so slightly to measure the slack between the ring and pinion, the "backlash": Dial indicator: The axle reasssembled and ready to go back in the car: We have accumulated 400 miles on the new gearset and everything is operating correctly and quietly!
Thanks for the positive feedback. New gearset came from Speedway Hot Rod Works was very helpful as we had to bother them several times with phone calls regarding technical questions.
Nice job. Done just the way it should be. Should be good for another 80 years. Beautiful roadster BTW.
I noticed the oil stains on the cardboard covered bench. You mean the banjo has oil inside too? great post, good to see a father and son working together in the shop.I'll be trying this soon, but alone.
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