#10 oil is the standard. I used a 50/50 mix of 10 and 15......so 12.5# and it feels good. About like a click stiffer on my adjustable ones.
15# oil would be okay for the track, bit stiff for the street. the 12.5 works great.
Best way to do it is pull the little star head drain bolt......pump it a few times , the old oil will squirt across the room out. Then actuall totally submerge the damper in the new oil in a pan and pump it a good 20-30 times. It will bleed all the air out. Then start the screw back in while submerged.
No problem. Just make sure you get all the air out. You will see what i mean about pumping it back and forth once you get playing with it.
You can actually pour a little of the oil out of the quart container and then just cut the top off so its a big old hole......and submerge the damper end with the hole in and pump away......you will see the bubbles float up. When you see no more......your done
I changed my damper fluid yesterday. I had some 5# Amsoil Shock Therapy, laying around, and decided to try it. At first, I didn't think it would be stiff enough. To my surprise, it firmed up nicely, compared to the way it reacted when I first pulled it off and pumped it. We'll see. Maybe have to go to a 10#.