Here is an article I wrote on the subject in 2010. This was after I had struggled with this situation several times and thought, "There has to be a better way..."

I have attached this short article as a pdf file to this reply.

Good Luck,

Dave Clark

Dave, the article is accurate and a superb fix for a difficult and pesky job. 

The only addition might be to advise 7093 how to align and drill the hinge stock. If he has not done this before, it takes patience and the doors must align with the wing structure perfectly. 

If it doesn't work, try again. The point is that the holes must align perfectly. 

Pat

Thanks for the article. If you have a way to assure a proper fit by aligning and drilling the hinge stock I would appreciate the advise. 

Well, use Dave Clark's recipe for the strip with nutplates. Your hinge stock goes between the strip and the lower skin of the wing (so, it is above the lower wing skin and below the top layer). Once you have made up the strip and the nutplates you will dimple the hinge stock (that you already cut to length) and then drill it - you must use a drill press, so don't try a hand held drill. The hinge stock is clamped to the base of the drill so the holes are accurately drilled. For what it's worth, I like to use a step drill on all aluminum hole cuts simply because drill bits tend to rip. Harbor Freight has inexpensive step drill bits. 

Once the hinge and Dave's strip is fitted to the wing and there is no misalignment of the screws, then proceed to the door itself. I have the hinge in place, and I tape the door in place, aligned equidistant in the center for fit - this is important. Then I use a punch through the center of the door's holes in the very center of the hole, but since the hinge is thick the punch might not leave a mark so try a fine point marker and just put a dot where you plan to drill. The holes must line up perfect]y - when you order the hinge stock (from Spruce or Webco) it needs to be drilled, so the holes have to be perfectly aligned by you.

The critical bits - do Dave's strip, align it with the hinge, and drill and fit. Then use painter's paper tape and tape the door in place, use the holes as templates, mark and drill. Do all drilling off the aircraft on a bench drill press. Remember, if the holes don't line up don't overdrill the hole - discard the hinge piece and start again, which is why you should order a few feet.

Sounds simple? It can be. Dave Clark's designed strip is a great idea - it will save you so much frustration. 

Once fitted accurately, then you rig with the connecting rod. Obviously, you want the door to be flush with the wing when the gear is retracted. The Comanche Service Manual has a description of tying a 9 lb weight on a string and suspending it from the door and ensuring that the door does not sag. The rod connection at the door might have a wobble - frustrating job - the door rivets need to be drilled out so the door can be taken apart to repair the connection. The point of the 9 lb bag and this sag test is because the gear well gets air swirling up inside there and it develops high pressure that pushes down on the gear door in flight - if the gear door sags it sags into the air flow, and slows you down. It needs to stay flush.

You haven't performed this repair before, so I feel for you. I've done it and it is straightforward, but can be frustrating so take your time. Remember what I said about a bench drill (drill press) - do not try to do this with a hand held drill.

A small tip - don't go rushing into this job and remove both gear doors from the plane. Do one at a time, one step at a time. Look at how the hinges are installed now, and use that as a guide. The major change is Dave's strip (great idea). Just be patient.

Thanks for the tips. When I looked at the job it looked like a challenge. Thanks for the tips.