We have 4 UMCs and a couple of them are getting 2-3 years old and the doors are finally starting to get tired. If you have a UMC or worked on one then you know how heavy this door is. I was wondering if anyone has worked on the doors or changed the rollers out yet. If anyone has any tricks or tips that would be great. I looked thru some of the maintenance manuals but I didn't see a breakdown on the UMC doors. Thanks.