R52 rock door

We have a 1994 R52.  We have had it for half a year now(first harvest with it) and all we have had is trouble with it.  When we bought it we were told by the guy that it was a very good and reliable machine.(he is a freind of ours so I trust him in what he said)  We used to run and M3 and never had any real problems with it.  We got though beans with minor problems( manly with the head) but we have had an on going problem with the Rock door opening up all the time.  We started corn today with it and the moment the corn passes over the door it opens.  So we went back to the shop and tryed to adjust it but we still can not keep teh door shut. so my question is, Is it our machine, the rock door in general on the R52 combine's, the fact that this is our first Rotor and we dont know what were doing, or all of the above? 

Chances are VERY good that you aren't doing it correctly. Is the door latching mechanism tripped open when the door blows open?? or still closed??????? If not opened, you aren't getting it closed all the way and it's falling open without tripping the latch(because it wasn't closed to begin with). Clean all the way around the door sides and at the concave front area with a putty knife to be sure there is no packed dirt causing the door to not shut 100%. With the latch opened, slam to door shut really hard.....then open it and slam it again. ...do this several times to get the feel of it. Slam it shut once again and continue to hold the wrench so it won't fall back open(takes two people for the inexperienced) and then the second person latches the latch shut. If it blows open and is actually tripping the latch, tighten the springs on the door latch a turn at a time on each spring to put more tension on it (this is in the owners manual). If the door has a "hump" kit on it, this is aggrevating the problem. A standard door is perfectly flat. That door is a good setup if adjusted properly and is operated correctly.