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Old 10-02-2020, 03:48 PM   #10
rotorwrench
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Join Date: Jun 2010
Location: San Antonio, Texas
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Default Re: Rear Axle Taper - What It Does

The taper shaft design has been around since the dawn of the industrial revolution. It's a simple way of joining a shaft with a hub and not have problems with fretting as was the norm with splined type designs as long as they are maintained in clean and tight condition. Shear keys were added to protect the shaft from breakage if the taper joint started to loosen. A sheared key is dead give away that the joint was too loose. The male and female tapers must be clean as a steam whistle before assembly. No oil or lube of any kind. It's good if the key is snug in both keyways but it will load up against a loose key pretty quick in service. Ford made the axles strong enough to take a torque of 100 Ft/Lbs but I don't know if that is what was intended or not. Suffice it to say that it should have been tightened to a level that it could just barely reach a cotter pin alignment with a fairly long handled breaker bar type tool. The torque should be rechecked after a period of driving that would be sufficient to apply multiple torque loads in both forward and reverse gears.

A good way of dealing with wear and tear problems with these friction joints is to start looking for parts that are in better condition than the problematic parts. Folks can keep beating the horse but one day it's going to break and leave the owner on the side of the road.

It's natural for worn out tapers to pull inward far enough for the drum to rub the backing plate. If it's that worn then start looking for better parts. Shims make a poor fit for a tapered shaft type joint.
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