Reseal - replace the fixed leaky pushrod tube by an extensible one (Click on any picture for a bigger size one)
 

Remove the valve cover, pull down the clamp (red arrow), remove all 4 screws (yellow arrow)
 

Have fun!

Old leaky tube.

Remove the rocker, 2 13mm screw.
 

Remove pushrod

Cut the leaky one, pull out.

Remove old seal
 

Grease the O-ring

Add some Locktite 518 or some similar stuff.
 

Insert the new EX tube, push hard on it.

Put back the rocker ass. and MAKE SURE THE LOWER PUSHROD IS WELL ALIGN IN THE CENTER OF EACH LIFTER. Push the bottom part of each rocker.

Use a flashlight to make sure they are well align. Check all 4. When done, put the valve cover back and tin.