why would the zerk on the joint not grease the bushings, it's gonna fill the entire casing.
either way would /should work. zerk on the bolt needs matched to a cross drilled ball. or an external fitting directly into the joint casing.
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As I understand it, there are two pieces to this. First, is the assumption that grease is able to fill the entire casing via the housing zerk or the drilled ball. Second, if one were able to fill the entire casing via these ports, you risk blowing the poly race out of the side of the housing due to the pressures involved in filling the entire casing.
I'm pretty sure Blaine described this earlier in this thread.