I have a Marlin kit I got from Skip a bit back. I haven"t had any problem with the seal, did have a servo extending pas t o-ring. An easy fix when found. This has been a great kit. Have changed the gear around. I'm now tryind to get a replacement pressur hull and will fit the motor upside down from instructions( have to brace it) and put the rear servos below. This will get me a couple things. One. have had water in motor and corrodes. Two. frees up the space in front of the rear bulkhead that had the servos. Will also enlarge the tank. Don't ya love to experiment! Good Luck!