The grease fitting should be in this area, as close as possible to exactly centered across the housing. The hole will penetrate the housing about 26mm (I measured thicknesses of just over 26mm to just under 27mm) before entering the space between the bearings; the space is 8mm wide, so it will be necessary to mount the unit in a drill press for accuracy.
It's important that the final bits of swarf from the drilling be extracted from the hole. Even a small bit of loose steel will be very bad for the bearings.
The fitting should be installed at 3:00 on the housing with a relief hole at 9:00. Grease should be injected slowly while turning the hub. There will be a tendency for the new grease to simply flow around the cavity between the bearings; turning the hub should encourage the new grease to enter the bearings.
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| "A" is the 8mm-wide space where the hole must enter the bearing area. "B" is the 9mm-wide band around the housing where the hole is started and where grease will be injected. |