Zerks

Got under the truck this weekend to grease drive shaft but noticed that the zerks are completely rusted. Would it be ok to go ahead and put a grease gun to them if I took a wire brush to them first? Just afraid of rust getting pushed through when the grease is applied.

 

Try to wipe off the 'ball' that's exposed on the top. That's the critical part. You could try to get grease in there... but the ball might be seized. You'll know almost immediately if the ball is seized (the grease won't go in and will just come out the sides).

You could replace them.....
Some zerks are 'press in' and others are 'threaded in' - I'm not sure which ones the tacoma has. You can try to unscrew 'em..... but they're made of soft metal and if they're that rusty, they'll break. If they break, use an 'Easy Out' to remove the stud left in the hole.

And honestly? If the zerks are rusted, then there's probably rust inside the bearings that you can't see.

 

I always push in the ball in the zerk with a punch, to free it up so the grease WILL go into the bearings.
Most are replaceable too if they're too corroded.