EB4 S2 Pro RTR shock rebound setup possible ?

[Dandare]

These are the shocks:



I know how to set up the rebound but i just can't seem to set it at all with these kit shocks, eg if i set for 3/4 rebound & close them up i'll get 1/4 rebound only. If i put any more oil in the shaft won't compress fully. If i do seem to manage to get 1 or more set then after one day's racing if i re-check them all the rebound has gone & they'll be none though if i strip them they're still full of oil. These shocks don't have a bleed screw, foam compensator etc etc, just cheapo basic shocks, lol.

Is it simply because these are cheap rtr shocks or could i still be doing something wrong ?

Thanks.