Purpose of plastic caps in end of axles?

John H

Rush SR Owner
Jan 1, 2023
De Leon Springs, FL 32130
There's a plastic cap in the end of each side of the axle within the CV joint. Two of mine got eaten by the joints (one outboard that had gotten loose and one inboard that was always tight). Best guess is to prevent metal on metal contact against the splines when not fully assembled to the bearing or diff, but nothing when fully assembled? (don't want to put them back or need new ones if necessary)
The plugs are for stoping metal to metal contact between the end of the axle and the concave surfaces of the CV flanges. Contact is not normal there and once the CV joints are bedded in the axle stops are kind of redundant. When the CVs are new they will typically be tight so it is common for the axle to make contact at one end. Once the CVs are bedded in you should actually be able to slide the axle back and forth along its axis, in an out of the CV joints. The axles stop is what limits this. However if the shaft is moving freely it will center itself due to the CV loading. That said if a CV fails or gets stuck the shaft could then make contact with the flange. The only movement however is that of the suspension movement, they are rotating together.
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@David Hosie, Where can we get replacement caps? At least one of mine also popped out (the inner of the two CV joints), would love to replace the eaten one.


Call Blair, pretty sure it's this part: