We're working with a 1998 Jeep Cherokee XJ.
Got a question. I went and ordered some 1/4x28 Grease zerks and they fit in several places, however the ball joint zerk is a different size and Im not finding anything at the store or on google that resembles even close to the black zerk.
The second picture is where this strange zerk was found?

The gold zerk fitting is a 1/4x28 that I bought. The black one is what i pulled from the ball joint (no clue???)

 

Zerk fittings come in several different configurations, ball joints need an ultra low profile on the lower one. I had to go to 3 different auto parts to find some.

 

Do you know what size it was? Im completely new to cars.

 

Chances are, any aftermarket parts, like tierod ends, will have metric zerks, indeed the originals might be, as they would've been bought in & not part of the original AMC architecture.

 

Yup, metric is possible. I haven't run into them on a Jeep yet, but there are also drive-in zerks that have ridges and not actual threads, which get pressed in.

 

If the threads on the outside and or the hole inside the zerk fitting is fine , clean and reinstall.. To clean soak in hot soapy water and blow dry. Make sure the hole of the zerk is clean enough to see thru. Do not use a hard pick to clean the center out. Soft wire IE copper can be used . They (the zerk) can be cleaned if you can not find the correct fitting size.