Originally Posted by
surfandturf
Was just the left door for a long time, one pilot who has been here since aircraft was new said it was always a little odd but never as bad as is now or has been for the last few years. The right door is now just as bad after the mechanic tried to make an adjustment to fix a grinding noise but loosened up the wrong bit and of course couldn't get it back where it was. Based on that I'm sure it's just an alignment and adjustment problem, the issue is we cannot seem to find the right technique. It feels like the door is too far forward or back and it tries to push itself when it enters the curved part of the track as it goes into the airframe opening. The primary adjust problem area are the two bolts under the cover on the middle roller that bolts to the middle of the door. The manual gives no help other than "adjust the door till it works with a 5mm gap" If I could watch how them put these on the aircraft on the assembly line just once I'm sure everything would make sense but that's obviously impossible being in the USA. Gaskets are ok and still original, its a binding on the curved part of the track that the door just wants to pop back out.
Apart from the obvious it is pretty critical that the forward upper cart is in good shape. You cant just fit it and expect it to work. When it is all bolted in place but still loose so you can move it slightly on the fasteners there is quite a range to get it in the sweet spot. Don't just bolt it all up as it sits. Goes without saying that if the rollers are worn undersize or the track is worn (hard to see without torch and mirror) you will be pushing it uphill so to speak. The roller axles need lubrication pretty regularly and normally the vertical axis one does most of the work. If you here grinding you can tilt the cart within it's attachments when it is still loose as there is no pressure on the vertical roller and it's dragging on the track. There are peel shims under the brackets for the two forward rollers but I doubt they need adjusting.
Also check the gap to the forward door. Any change with the front door open or closed? Also check that the forward upper cart is not too far forward and hitting the end of the channel.
When the door is in the correct closed position have you tried backing off the fasteners to remove preload then re-torque? FWD upper and MID aft.
If you watch the upper part of the door inflight it is interesting! Check that you have steel bracket arms because alloy ones do crack.
It takes a bit to get them smooth but they should just be able to be closed with one finger as you say.