U-joint Orientation ?

The zirc should face inwards toward the shaft and be oriented to be easy to grease both ends and the slider. That's how I do mine anyway. I've had some that the only way to get to the zirc was with a needle greaser extension. What a pain.  John

Shaft rotation shouldn't have anything to do with it.  The zerc has a spring/ball to keep grease from coming back out.


As mentioned above, it needs to be installed so it can be greased, usually this means aimed toward the driveshaft (aimed at each other from each end)

There are some that still require a needle style end on the grease gun, as there's no room between the yokes to fit a grease gun end.

Many of the newer grease guns have a 'fat' end, where older American made ones had a bit smaller diameter end, and will fit between the yokes.


They also make u-joints with the zerc fitting on one cap, makes it easier to grease, but has some drawbacks.

1: They tend to get ripped off if you go offroad, because they stick out.

2: The grease is being pushed from one cap, to the other three, and doesn't always flow equally (may starve one or more ends)

Whereas a zerc in the cross section pushes grease fairly equally to all 4 caps.