Are you filling the lifter body with oil first!
Here are the steps to correctly bleed a lifter:
With the lifter disassembled fill body with oil.
Start plunger (with spring) into body with hole in plunger lined up with the hole in body.
Using a small rod (I use a WD40 spray tube)unseat the check valve by pushing down on it.
While unseating the check valve push the plunger down into the body until both the hole in the body and plunger line up.
At this point you install a pin (I use the shank of the largest drill bit that will fit in the hole) in through the hole.
This should hold the plunger down while you put the pushrod seat and snap ring in place.
Remove pin, letting the plunger return to its resting position.
Lifter is ready to install.
This is spelled out in the shop manual.

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