How to dismantle RST 381L forks I have cannot remove the elastomer/spring adjuster assembly from the top of the forks. 
I can remove the bottom of the forks. 
You undo the assembly for adjusting the tension with a 10mm hex key. Inside this 10mm socket there is a smaller hex for adjusting the tension. 
When I have the assembly undone and pulled out from the top of the leg it will only come out about 30mm and stops and there is a spring pulling it back in.
I found this diagram and it is nearly the same. but no hex used to undo the tension assembly or adjust it.
RST 381EL service manual
I had the same issue and was just about to give up...I don't imagine this is the best way, but it is what worked for me.

Take the bottom covers off.

Take the caps off the top and spraying brake cleaner inside the tube to melt the old elastomers down. I let that sit for a couple hours and then sprayed some Simple Green down in there and let that sit for a couple more hours. Flipped the bike over and tapped (banged on out of frustration) the plastic tubes coming out of the bottom until the springs and old elastomer and all the filth of the last 20 years came out.

Be sure, if you decide to do this, to cover any painted surfaces. You don't want to get brake cleaner on there as it will eat the paint right off.

Good Luck!