Through heavy use I found the standard aluminum hinges literally wore out to the point where the hinge had so much play that the hinge paint was being scrapped off from the other leaf (see photo). In addition, the connection between the hinge and the door can become loose and work the rivets around and destroy the top flange of the door. It appears that the larger the door the more likely this can occur because the gas spring loads must be carried through the end of the hinge. After buying a new 6 ft door I decide a stainless hinge would be a much better choice for longevity. Fortunately I could buy a standard hinge and with modification, it would fit just like the OEM hinge. I used nuts and screws instead of rivets – I think they do a better job holding onto the door.
The hinge modification turns out to be the most difficult part. The OEM hinge has one leaf reversed. So for the new SS hinge I had to remove the center pin, flip one the leafs over, and re-insert the pin. Tools required are a 1/8" punch, hammer, bench vice, lubricant, and especially...determination! Rotating one leaf as you hammer helps but it slow going. Getting the pin out seems harder than putting it back in. Before re-inserting the pin I ground a slight point to help it find its way into each successive leaf. Lubrication is very important (both directions). Stainless has a problem when it slides against other stainless - it can gall - which is like smudging only the two surfaces lock together – its bad news when this happens. Lubrication is the answer to galling. Leaf reversing changes the hinge final length so do your final cut of the hinge after. If you're into the polished look, polish the hinge before installing – it's much easier. I sand with successively finer grits of sandpaper (100-600) until I can use the buffing wheel.
I next removed the bay door from the coach (requires removal of trim piece above hinge). I marked where the trim piece holes are on the coach wall. Since I decided I would create new hinge screw locations I had to make sure they were not in the way of trim piece holes.
Removal of the old hinge is straight forward – drilling out the old rivets. The holes in the door will be reused so be careful about drilling. While the door is off I like to wet sand and polish the gelcoat - especially that top edge where the hinge will be in the way later. It's a good idea to make a hinge gauge tool before you remove the existing hinge (see photo). It just a piece of (anything) with the right step height in it. Since you have to drill new holes in the hinge, this tool helps you place the hinge the same position.
Using the hinge gauge for placement, I transfer marked the door holes on to the hinge face. Since marking and drilling can drift, I drill a little oversize for the #10 screws. I count on the clamping force to hold the hinge in place – not the shear force of the fasteners. Drilling in stainless is harder than plain steel – good bits made for stainless are well worth getting. On the 6 ft doors I added polyurethane glue between the hinge and the door to help carry the high shear load imposed by the 120# gas springs. I did this only on the last 4-6" of each end. In some locations the hole was positioned too close to the door inner wall – so on those I ground a flat on the washer to make it fit.
For attaching the other leaf to the coach wall you need to position the door (with its new hinge attached to it) in the closed position. This takes a variety of block and shims at each end and a helper to help hold it in place. I use the neighboring doors and/or fenders as a guide to the vertical position. Making sure I'm clear of any trim piece holes, I drilled pilot holes at each end through the hinge and the wall of the coach in approximately the same vertical position as the original holes. I installed temporary screws through the pilot holes and verified the door was positioned right. I then drill the rest of the pilot holes. While the door is still temporarily in place, reinstall the trim piece (using screws on either side of door) and transfer marked the hole locations on the new hinge. After removing the door I then drilled and countersunk the pilot holes for the permanent screws (same as original). I then drilled clearance holes for the trim piece screws to pass through. Upon reinstallation, I like to put a dab of silicone under each screw head in case there's leak that gets through the trim piece. And of course, the trim piece gets silicone under its screw heads as well as its top edge.
As an additional detail that I will do on future replacements is to trim the excess hinge that extends beyond door on the inside. As is, this extra bit of hinge wipes past the bulb seal and scraps the surface rough and will eventually accelerate replacement of the bulb seal.
The detail picture is of the first door I did, which was about 8 years ago and is still holding good.
Parts list: (all McMaster-Carr p/n's McMaster-Carr (http://www.mcmaster.com/#) but can be found elsewhere):
Hinge: 1582A341(4ft), 1582A343(6 ft): 304 stainless, 2" open width, 1/8" pin, .060 thick
Screws: 91770A830, 18-8 stainless, 10-32 x 5/8" long, Truss head Phillips
Washers: 98017A640, 300 series stainless, .44 OD (important), #10 screw, .06 thick
Nut: 91831A411, 18-8 stainless, Nylon locking, 10-32 thread
Looks excellent John. Very nice work. Thanks for posting that. No doubt I'll be referring to it again one day soon. :)
Your doors have 120 lb gas springs? On my U225 they're rated at 20 lbs. Are your doors really that much bigger/heavier? Interesting.
Steve
James was offering SS hinges as a option at Xtreme.
The aluminum hinges on my 1996 U320 are not worn very much, however, three doors in the last year, have torn off the hinges leaving the rivets in the piano hinge and the door on the ground (scratched).
The pressure gas struts have a "90" on them which I believe is for 90 pounds, not 120.
I repaired 5 of the 6 four foot doors and 1 of the 2 eight foot doors by using "JB Weld" to attach a 3/16 wood dowel to the fiberglass where the rivet holes are and then two layers of reinforcing glass cloth with fiberglass resin. I then used 1/4 inch stainless bolts with nuts and washers. These bolts hold much tighter than the rivets being replaced. I am just replacing rivets with bolts on the doors which were still intact.
After the first door partially tore off last year, I checked all cargo doors and found, aluminum rivets in some doors, stainless rivets in others, and plated steel in others. I also found small bolts added between the original rivets. Most of the rivets had loosened and there was movement between the hinge and the door.
I used 1/4 inch stainless rather than #10 because they are readily available and a little stronger (stainless bolts are weak compared to steel bolts).
Cargo doors look and work good now.
A couple of months ago we had our port side engine bay door open. It fell off when my wife tried to close it All of the rivet holes in the fiberglass had broken. I purchased a 3/8" x 5/8'" stick of aluminum and fit it to the inside of the door lip. This required grinding a 3/8" wide notch the entire width of the door, down to the depth of the aluminium strips that are in the door vertically. After cleaning and roughing up the aluminum, I applied Marine-Tex epoxy to the notch/aluminum and clamped in place. At the same time I restored the broken fiberglass on the lip. After drying I sanded the excess epoxy and marked the mounting holes positions. I elected to use 1/4-20 SS bolts, threaded directly into the aluminum, utilizing Loctite. After getting it all together I noticed that the latching post did not line up with latch and probably never did. In the past when I tried to open this door it required a firm pull. I repositioned the post and the door now opens/closes with little effort.