I think I sold that arm rest some time back. You can use JB Weld Plastic Bonder seen below to repair partial cracks in the plastic. Just apply liberally from the back and in the joints and press together where it will be undesturbed for several days to give it plenty of time to cure. You can use whatever you like on the front to fill in the slight crack you might see and lightsly sand smooth without taking out the plastic texture around crack.
Ok. Thanks, that sounds like the instructions i remeber. I just couldnt find the thread