Mid ship entry door

[TedCalvert]

No one has mentioned this here, so maybe I'm mistaken, but I had always heard that GMs were monocoque, dependent on the skin for structural integrity.  Therefore cutting any holes for slides or relocated doors was like cutting a hole in an egg.  Unless you correctly framed around the hole, one had a good chance of major problems.  I know my '04 has very little framing.  Eagles, of course, are considerably different.
Not to  be discouraging, just cautious.
Good luck.

[RJ]

Eric -

Ted brings up a good point that yes, has been overlooked.

Your 4107 is of a monocoque construction design.  The exterior skin is, in fact, the main frame, held square by the floor and the bulkheads.  It's not like an Eagle, where there's a "birdcage" frame behind the skin that takes all the loads, the skin being just decoration.

If you have the shell gutted, look at the heavy stringers running forward from the rear window on the roof's interior that come almost to the center of the rear bay.  Those actually spread the load of the powertrain's weight into the structure of the coach, as an example of how the monocoque design works. 

That being said, yes, you can install a mid-ship door, there are a couple 4104's running around both on the East & West coasts with them.  However, the 4104s have much heavier aluminum siding than the 4107s - it's one of the ways GM cut costs with the later models - so their chassis' are a quite a bit stiffer.  I know of a mobile dentist hear locally that put a wide lift in the side of a 4106 above the first baggage bin so he could accommodate wheelchair patients in rural areas.  Worked fine for about five years, then the coach had to be scrapped because it collapsed in middle - he hadn't reinforced the chassis when he cut the hole for the lift.  He's now using an MC-9 that came from the factory with a wheelchair lift, thus designed into the chassis.

The point is - yes, you can do it.  BUT - you'd better be prepared to reinforce the structure to make up for the loss of rigidity from the new hole.

Oh, and for heaven's sake - don't forget handrails!!  And possibly some way to cover the hole in the floor created by the new stairwell while underway so somebody doesn't end up falling into it!

FWIW & HTH. . .

[krcevs]

Eric,
RJ is correct. The ribs, steel and aluminum siding and the aluminum channel all work together to support the weight and shape of the bus. If you take a look at my bus build page you will see one of the main structure ribs that was cut and the aluminum channel that helps spread the load across the whole bus structure. I have been lucky,, in that my bus has not shown any damage to the rest of the structure due to the door being hacked into the side of it. I believe that due to the floor and the aluminum channel running the length of the bus not being compromised is why it held up.
Good luck with your project and please send some pictures!

Ken