Grease zirk on 68F250 4x4 front axle

[Lambo]

Starting to do some routine maintenance on the 68F250 I purchased in August. While lubing all the grease zirks I could find on driveshafts and front end, I found one located on the driver's side back of the 4x4 axle hub, but not on the passenger side. Passenger side has a plug instead of grease zirk. I have searched this site to no avail. Should there be one on both sides, on neither side? Doesn't seem to make sense to be on just one side. What does this lube through the zirk? Thanks all.

[eggman918]

That sounds like a "field fix' to me the closed knuckles are lubed with gear oil but they drip badly when the ball wipers get worn and I've seen people use grease instead of oil to reduce the leaking. This is only a guess as to the previous owners motivations but Ill bet that was their thinking
I was using liquid 'chain lube in mine before I swapped in a '76 open knuckle HD44 It reduced the drip rate by quite a bit without affecting u-joint or spindle bushing life.

[Lambo]

Thank you Steve. I was wondering if it might not be something like that. I would like disc brakes on my truck so thinking about swapping out either axle ends for the open knuck with discs or complete front axle assembly from a late 70's unit.

Lambert

[hfdco4]

You pretty much have to switch to an open knuckle to get disc brakes.