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-   -   Floor replacement - off with the shell or the underbelly? (https://www.airforums.com/forums/f36/floor-replacement-off-with-the-shell-or-the-underbelly-89975.html)

mkeilx2 04-16-2012 08:00 AM

Floor replacement - off with the shell or the underbelly?
 
We are ready to replace the sub floor and look at frame for any weakness and check axels. In our internet search we have see two methods.
1. remove shell
2. remove undebelly

What are your thoughts on the pros and cons of each and if you did one way would you do it the other way if you got a mulligan.

Thanks!

~Mark and Martina

aluminitus 04-16-2012 08:08 AM

I am in the middle of a shell-off replacement of the subfloor of a '62, so I don't know for sure how it would be on a '77. My '62 required that the shell come off to replace the entire subfloor. The outer shell is riveted onto a j-channel, with the underbelly sandwiched between these two pieces. The j-channel is then screwed onto the subfloor, making it necessary to take the shell off, then the underbelly, then the j-channel and then finally the subfloor to do chassis repairs. On a later model, you may have banana wraps (curved pieces that connect the j-channel to the belly pan) in which case you could just remove the rivets and get a good look at your chassis. A frame-off is a LOT of work, but there is nothing like knowing that everything you put back together is now solid and will last many more years.

mkeilx2 04-16-2012 08:14 AM

Aluminitus - THANK YOU
Yeah, we know it is a ton of work. Just gutting the sucker was interesting! Now we have the interior skin off, the old insulation out etc. Would rather do it all and have it in good shape.

SO it looks like off with the top and bottom. Makes sense.

Belegedhel 04-16-2012 08:49 AM

1 Attachment(s)
I am just about to start the re-assembly of my '73 globetrotter. I replaced the entire subfloor, and concluded that the best way to do it was to remove the shell. I have seen other threads where the floor was replaced in halves (without removing the shell), rather than full sheets of plywood that go from sided to side, but I decided against this for the following reasons:
--There is a funky channel that attaches to the edge of the plywood with a "c" profile, but then has an flange going up vertically that the shell rivets onto. It is a tight fit, and I was concerned that insterting a piece of new plywood from the inside, and getting it to lie flat and mate tight in the middle of the trailer would take more talent and patience than I have.
--My frame rot was evident from the underside after removing the bellypan, but when I finally got the subfloor removed, I found that I would need to take the frame to a welder to get large sections replaced.

I built a set of gantry frames that I used to lift up the shell so that the frame could be pulled from underneath. This worked pretty slick. I worried that I would end up with a bunch of lumber from the frames and no immediate use for it, but so far, I have gotten tons of use from the frames as I have been using them to hoist the trailer frame into the air, flip it over so that I can work comfortably on the bottom side, suspend it "vertically" during painting, etc.. My setup in pictured in the attached.

If I were to do one thing over, I would lift the shell off of the frame without messing with the belly pan, then I would use my lifting frames to turn the trailer frame upside down, and then I would pull off the belly pan and work the underside. I spent way too much time with crusty debris falling in my face.

Good luck!

marzboy 04-18-2012 08:29 PM

Remove the shell.

marzboy 04-18-2012 08:31 PM

Quote:

Originally Posted by Belegedhel (Post 1134421)
I am just about to start the re-assembly of my '73 globetrotter. I replaced the entire subfloor, and concluded that the best way to do it was to remove the shell. I have seen other threads where the floor was replaced in halves (without removing the shell), rather than full sheets of plywood that go from sided to side, but I decided against this for the following reasons:
--There is a funky channel that attaches to the edge of the plywood with a "c" profile, but then has an flange going up vertically that the shell rivets onto. It is a tight fit, and I was concerned that insterting a piece of new plywood from the inside, and getting it to lie flat and mate tight in the middle of the trailer would take more talent and patience than I have.
--My frame rot was evident from the underside after removing the bellypan, but when I finally got the subfloor removed, I found that I would need to take the frame to a welder to get large sections replaced.

I built a set of gantry frames that I used to lift up the shell so that the frame could be pulled from underneath. This worked pretty slick. I worried that I would end up with a bunch of lumber from the frames and no immediate use for it, but so far, I have gotten tons of use from the frames as I have been using them to hoist the trailer frame into the air, flip it over so that I can work comfortably on the bottom side, suspend it "vertically" during painting, etc.. My setup in pictured in the attached.

If I were to do one thing over, I would lift the shell off of the frame without messing with the belly pan, then I would use my lifting frames to turn the trailer frame upside down, and then I would pull off the belly pan and work the underside. I spent way too much time with crusty debris falling in my face.

Good luck!

Wow! That is really slick!!

RSantiago 04-23-2012 09:04 PM

Sweet rig belegedhel! Just finished gutting my Ambassador and am researching the best way to do a shell off. Your way looks good. Nice job.

Belegedhel 04-24-2012 02:39 PM

Thanks--I have three 1 ton chain hoists that I use to manipulate the frame. One is attached to a sling at the hitch, which allows the frame to rotate in the axis without binding up. I then use the two other hoists to control the two rear corners of the frame (one is pulling up, the other is letting down to effect the flip).

I was worried that things could get dangerous withall this manipulation, but as long as neither hoist or slings fails, it is no more dangerous than just hoisting up the shell. Just have to be conscious about not operating a hoist from within the frame rails or something, which could lead to serious injuries if something let loose. I'll post a picture of my frame in the air being manipulated later this evening.

It definitely feels like a luxurious way to work. I have also used one of the lifting frames to install and remove the axle a couple of times. It would be pretty awkward to do this solo otherwise, and I work alone a lot.

For a bigger trailer frame, one might consider a beefier cross-member on the lifting frame (maybe a 4x6). I didn't do any stress/strain calcs for my 4x4 cross member, but I don't see any dramatic deflection when supporting the trailer, so seems to be OK. Haven't had any issues with stability (sway, rocking, etc).

Belegedhel 04-24-2012 08:36 PM

2 Attachment(s)
Here are a few pics demonstrating getting some extra use out of my shell lifting frames: lifting a new axle into place, and suspending the frame sideways for POR-15ing.

BNM87 05-02-2012 07:06 AM

Wow! that's awesome. How did you move the shell over to the side of this hoisting contraption?

Belegedhel 05-03-2012 07:11 AM

I actually scooted the frames over the shell, lifted it up, pulled the trailer out, and set the shell down on the ground. I then dragged the lifting frames over to where I parked the trailer frame and commenced with the trailer manipulations. The lifting frames can be moved by a single person without too much trouble.

DFlores 05-03-2012 07:34 AM

Belegedhel, what type of reinforcing did you use to lift shell, did you use 2x's at roof or did you attach to ribs?

Belegedhel 05-04-2012 07:28 AM

I didn't use any cribbing at all. I read a lot of threads, and it seems that the opinions vary widely. Some people insist that bracing is necessary whether jacking the shell up from below, or lifting from above. Some insist that even if you are lifting from above, the shell will change shape without the bracing.

I have also heard the opposite, that the beauty of lifting the shell from above is that no bracing is required. Seems that I had heard the rumor that this is how the trailers were originally assembled (no bracing, lifting from above), and some professional restorers had also advocated the lift from above sans-bracing. I chose to test the latter hypothesis, so have not braced at all. The only drawback I have seen is that when it came time to lower the shell to the ground, I had to find little blocks to set at the bottoms of the ribs to support the shell, otherwise the weight of the shell would have been sitting on the lower edge of the skin itself (at least along the lengths of the sides, because the C-channel remains on the plywood).

I should be putting the shell back on in a week or two--then I'll know for sure whether the shell changed shape or not.

195Pilot 05-04-2012 11:20 AM

I have been researching shell removal using this method. As a matter I have ordered chain hoist. I assume you pulled up through the vent holes in the roof? What did you use inside the on the roof to attach the chain hoist to?
i have gutted the interior and removed only the bottom interior skin,as my problem is not rotted floor but rusted out frame. I would like to keep the a/c and rest of the interior skins intact, do you think this will cause problems? Also with the upper skins left in the shell less distortion, but more weight.
What do you think
Thanks, Jack

Belegedhel 05-05-2012 07:54 AM

Jack,

I had a 2x8 that ran from end to end, stopping right at the edge of the interior end-caps. I drilled a hole in it for the antenna deployment shaft to come through. All my skins were off, so I wasn't worried about marring any surfaces, but since you are leaving your skins on, I would probably drape a mover's blanket over it. I then just wrapped some webbing slings around the 2x8, and ran my hoists down through the fore and aft vent holes and attached to the slings. My Air conditioner is still in place, but I did remove the interior lower unit venting/controls so that it would be flush with the ceiling. I had the original aluminum caps over my vents, and I removed all of the hardware associated with the vent just to be sure.

Be sure when you build your lifting frames that you keep in mind that you will have to lift the shell at least 14" in order to clear the wheel wells. Your hoists will consume some of the height capacity of your lifting frames, so be sure to take them into consideration in your design.

195Pilot 05-05-2012 12:14 PM

Thanks for the info. I have all the rivets out and ready to lift but the weather is not, winds are 20 to 30 and forecast high winds for the next 4 days. Thats life in the high plains.
I think I will have to have make a complete frame. Holes are rusted out from bow to stern so the shell will be of for a while.
Looking forward to your shell install keep us informed on how it goes.

Landscraper 05-05-2012 10:55 PM

Great project! I would highly recommend that you remove the rest of the interior skins. Start fresh. Its only a few more rivets...right? Trust me... I would bet you have leaks. I just put a 34' shell back on and it rained the next day. I was surprised were water was coming in. Honestly they leak like a sieve. Our is leaking mostly where there is no Vulkum. That black tar stuff they put on at the factory seems to be prone to problems. I will be removing that junk in areas and brushing in Vulkum. Good luck.

195Pilot 05-06-2012 01:51 PM

leaks
 
Yes I may go ahead and remove the other interior skins.
The only water leaks I had were at the rear separation and door,(no gasket) I have sat out in the trailer while it's raining and cant see any leaks also no tale tale signs of previous leaks. I know that sounds strange that an airsteam has no leaks.Now that being said I have approx. 5 gal. of black tar on the roof around the vent holes that a PO smeared up there, and it was not to improve the good looks of the camper. Thought I would address that after I get the frame straightened out.
My problem is the frame. I really am lucky this thing did not break half in two on the short drive home. The pink monster drooped down in the entire belly pan and rusted out the entire lower part of the frame. I don't mean alittle hear and there, the entire length of the street side main beam is gone, The only intact outriggers are at the step.On All of the cross members only the tops are left. There had been the famous #29 service bulletin preformed at some point and the bolted in bace is all thats holding it together. 6 of the seven sheets of plywood are in excellent condition, you can read the manufactures stamps and dates,(manufactured in 9/74)
This Bulletin also advised to install additional rivets in the rear quarter panels to Strengthen the bond to hold up the rear end. Well who ever preformed this little work of art took the service bulletin to heart. The bottom of the panels look like swiss cheese, and they used pop rivets. I will have to make new panels and replace, I knew 40+ years of rebuilding aircraft would come in handy one day.
Also on another note,all the veritcal ribs are riveted to the C channel at the floor level.In my research every thing I have read the vertical ribs are sitting in the C channel and not attached.
thanks for the advise,
Keep in touch

Wabbiteer 05-06-2012 02:21 PM

Another believer in the 'shell holds the frame up' club, eh? :)

Ribs all attached on my '73 - sometimes creatively when the rib has a 45-60 twist to it but they were all riveted - on both the C and double-C channels. (double-C channels clip onto floor edges and have ribs nested in second C-channel when shell lands on floor)

195Pilot 05-06-2012 02:38 PM

Yes and pop rivets no less! Those guys put alot of faith in a MISPLACED,ANGLED, WHOOPY JAWED pop rivet.
i'm really glad those guys were building trailer and not airplanes. The FAA would be pulling all there tickets.


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