8 1/4 vent tube

its tube ... someone told me it was a vent tube ... looks like stainless, coming out of the top of the axel casing

I understand. That's not what I asked. I asked if it does double duty by not only venting the axle but also holding down the brake line Tee? On an 8-3/4 the vent tube holds down the brake line Tee. Not sure on a 8-1/4

Did you click on the link I provided that shows one on Mancini's website? does it look like that one?