GMC Conversion to Permanent Bed
This is the conversion of the seating area in the back of a GMC Royal with center Kitchen to a fixed double bed with storage under.
In this version of the GMC there was originally a seating area in the rear with a small removable table. In our case we never used this area as a seating and only used it as a bed. It was therefore desirable to make this into a more comfortable bed and make the area under it more usable as a storage area. One consideration in this conversion was that all the house electrical both AC and DC were located at the very back of the coach and would be hard to access with a permanent bed over them and there was also a safety issue with the electrical being in less accessible.
Since we are both tall we also felt that we could deal with a higher bed and gain additional storage so we raised the bed several inches which I would not recommend unless you are willing to put up with a little inconvenience. By raising the bed we gained a storage area over the propane tank and over the generator compartment as well as under the bed.
I wanted the platform that supports the mattress to be light but stiff so it is constructed along the lines of older style hollow core door with two very thin skins of plywood with some very light wood stringers between to generate a very strong yet light structure.
Access to the storage area under the bed was of concern because we wanted it to be very convenient. I chose to set it up so that it is opened with a hydraulic system with the push of a button which has made it something that we use without a seconds hesitation. In fact it is so convenient that we frequently put things we want to secure back there whenever we leave the motor home.
The basic process started with removing the original seats and replacing the side panels with new panels that were at the new height. I then added a cross member from side to side right over the back of the propane compartment and the generator compartment. This was a cedar 2x4 and serves as the structural member that is used to hinge the bed platform to. The area behind this is filled in with a non moving removable panels under with the water pump is located on the starboard side and the storage for the electrical hookup cable is stored on the port side. A second cross member of 3/4"x4" walnut was then added at the front and attached to the back of the closets. A panel was then added across the center space from the floor to the height of the sides and cross members about 6 inches in back of the front cross member. This is the new mounting surface for the AC breaker boxes, charger, inverter, and battery switch.
Since we wanted the bed to lift the panel in front of the 2x4 cross member can't extend to the sides since the motorhome curves in and it would contact the walls before it was high enough to get access to the storage space, therefore there are two narrow panels on each side and one large panel forward of the 2x4 cross member. This works out just right because the standard mattress that we use is exactly the length of the center panel and lifts with the center panel. At each end of the mattress we have a block of foam as a filler to make it the same height as the mattress.
Doors were constructed to cover the electrical area that have space at both above and below to allow air circulation for the charger and inverter. These could be a little more elegant but what we have works for now.
The movable portion of the bed platform is attached to the 2x4 cross member with a long piano hinge.
The lift mechanism for the bed is a self contained electric/hydraulic unit salvaged from a Evenrude outboard motor with power lift.
In my original design the hydraulic system pushed up the bed by pushing on the bottom of the movable panel with only the piano hinge taking the strain at the back. This did not last long with the wimpy piano hinge that I had used and the soft cedar cross member that did not hold the tiny screws. I soon had to add a hinge mechanism as part of the lift that would take most of the strain.
On top of the bed platform we installed one of the Select Comfort Air mattress bed which proves to be the only bed that my wife (with arthritis) finds comfortable and I will have to admit I enjoy. In the standard double size that fits this bed conversion the mattress with independent sides creates a very small sleeping area for each person but it is still usable.
All this visually represented at Bed Conversion Picture Gallery