Trillium Jubilee Structural Rehab - Fiberglass RV
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Old 02-05-2020, 10:04 PM   #1
Junior Member
Name: Michael
Trailer: Trillium Jubilee
Posts: 15
Trillium Jubilee Structural Rehab

My first post, hoping for any guidance from this terrific group on my 1980 Jubilee restoration challenge. Please excuse any breach in etiquette if I've missed something.

On our first trip last fall noticed it was sitting a little low. A lot of bouncing but no tire rubbing. Visible frame rust added concern and distortions in the shell need investigation. With only 2 inches clearance above the 13” tires and the wheel sitting noticeably forward in the opening, so I'll be starting at the bottom and then work up from there.

Just removed the frame and the cantilever from the axle rearward drops more than 1” out of parallel with the front frame. Both fiberglass wheel wells have cracks in the front at the point where where the top frame tube lap joint ends.

Planning to replace the torsion axle that is stuck up at about 18 degrees and maybe add a tapered steel gusset under the rear frame running back from the axle to re-support the rear and some extra crossmembers to stiffen the floor in spots.

Included are some photos and some initial questions:

1. Does the axle welded mounting look original? Were brakes an option in 1980? The 10” brake drums are Dexter. Would they have fit on the original spindles?
2. Considering installing a #10 Torflex 3500 lb with 0 degree angle. Does that sound correct but I may later switch to 14” rims so would 10 degree down be too high? Also not too stiff.
3. Is the rear frame sag unusual or a common problem?
4. Does the crack in the wheel well look serious or more cosmetic? Since it’s on both sides equally, I think it’s the result of concentrated forces from the frame flexing, so I hope stiffening the frame will help.

Well, that’s a start for now. Reading about others experiences can be helpful so I’m happy to contribute for other Jubilee owners with similar issues.
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Old 02-06-2020, 08:34 AM   #2
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Joe MacDonald's Avatar
Trailer: Trillium
Posts: 1,015
looking at the frame transition, and the design of the body where it fits, I would say it probably is original.
My 81 5500 came with an axle with leaf springs, 7 inch drums and brakes I'm not sure if it was original or not, but I upgraded to a beefier axle with 10 inch brakes.
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Old 02-06-2020, 09:13 AM   #3
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Name: bob
Trailer: Was A-Liner now 13f Scamp
Posts: 3,196
i dont own this sort of rig

I am amazed you did this and I am sure you will figure all this out. Love all this and a chance to see this!


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Old 02-06-2020, 10:19 AM   #4
Senior Member
Name: bill
Trailer: 2013 Escape 19; 1977 Trillium 1300
The Mountains of North Carolina
Posts: 3,814
I would not be supporting the trailer by the pontoons, if that is what I am seeing in the wheel well picture. I would run a 4x6 across side to side (or a steel beam as it looks like you have done already), and I would have a big enough block of wood that the main floor between the pontoons is supported. But hey, I may be misunderstanding the picture.

Look how little support there is on the frame from the axle back, and compare it to the axle forward. No wonder it sagged after 40 years. Is there clearance underneath where you can run more metal channel side to side, and maybe double up the frame front to back in the rear section.

You've done the hard part. Now with the help of a good welder, I would beef it up. And I would add fish plates where the frame was bent inward and upward near the front.

Overall, like most of the vintage FG trailers out there, the frame is under built from a metal gauge standpoint. Heck even Escape had to change their frame design in 2013. To get these trailers light, steel is heavy. So manufacturers tended to use the least amount of steel they could.

I think the fiberglass cracking is a result of the problem, not the cause. But you will want to repair that area for sure. Its hidden, so you can go to town on it and no one will see it.

I like those adjustable axles, that would be my choice when I get around to replacing mine. FWIW, I have 14 inch tires on my 1977 Trillium, with original axle and about 4 inches clearance. In my case, the axle has zero drop.
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Old 02-06-2020, 05:56 PM   #5
Junior Member
Name: Michael
Trailer: Trillium Jubilee
Posts: 15
Joe, it's good to know that the axle mount looks original so I'll replace it to be similar. Clearly, the mount bracket needs to be welded in if it's serving to reinforce the frame at the lap joint. Dexter Axle said that their high mount bracket can be welded if care is taken not to build up too much heat in the axle tube that would degrade the internal rubber torsion rods.

I'm thinking of ordering the popular #10 Dexter Torflex 3500 axle rubbered to a lighter 2500 lb. load. Probably the #9 Torflex would be ok but it's upper rating is 2,200 lb and is typically supplied with smaller brakes. Incredibly, the Jubilee factory dry weight spec is only 1,485 lbs so I still can't see how the numbers work when you subtract the tongue weight from the axle load.

Bob, thanks for your encouragement. The support in this group is amazing.

So Bill, those are pontoons? Ok, I'll go with that, and follow your good suggestion to add more blocking under the floor. That could only help.

I struggled to find the strongest lift points observing deflection and determined that the ends of the pontoons appeared the most resistant. It was reassuring that they were also under solid sidewall that offered a continuous load path to the roof. Once the frame was out, I added stabilizing jacks to spread the load.

The greatest frame design challenge appears to be the 5-6 feet of cantilevered steel hanging behind the axle. At least the section forward of the axle acts like a beam supported at end by the hitch. Big difference that didn''t seem to be appreciated by the manufacturer. The factory fish plating at the tubing bend seems to be holding although the fiberglass is pretty well embedded into the steel. See photo.

Has anyone used the old auto body frame welting in remounting the fiberglass?
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Old 02-22-2020, 11:39 AM   #6
Junior Member
Name: Donald
Trailer: Bigfoot 5th wheel
Posts: 29
Leaf Springs

This trailer must really bounce around! I think you should go with a full axel (maybe adjustable) incorporating leaf springs.
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Old 02-22-2020, 01:47 PM   #7
Junior Member
Name: Michael
Trailer: Trillium Jubilee
Posts: 15
It's possible that this unit was abused on rough roads and/or under heavy snow loads. I'd like to hear from other Jubilee owners as to whether the back droop, wheel well cracks, top and front wall sag are common problems.

Since the Jubilee has a stick-built wood interior, it doesn't have the structural resilience of a molded fiberglass interior such as in the Trillium 4500. So the Jubilee is more dependent on the trailer frame for support of the shell.

The manufacturer may not have taken that into account adequately when this model was added to the line. However I am encouraged that the body is straightening out while standing re-supported off the frame.

So my trailer frame rehab plan currently underway is:

1. Replace the 2x3 x 1/8" wall rear frame rails with 2x3 x 3/16" wall tube for added strength in the cantilever.
2. Add a tapered gusset welded under the new frame rails from the axle rearward for reinforcement.
3. Add 2 or 3 steel crossmembers at strategic locations to resupport the floor and cabinets
4. Replace the axle with a new Dexter Torflex 2500 lb, bolted side-mount. Custom weld-in brackets will reinforce the frame lap joint near the axle.
5. Axle location will move slightly rearward to center the wheels in the openings. (Factory location is off-center to the front.) 10 degree down arm angle will provide minimal lift and maybe room for 14" tires at a later time.

Note that the Dexter Torflex axle is made-to-order. Configuring it was a challenge in order to specify the numerous parameters required for it to be manufactured to fit this application and with preferred features. That could easily be the subject of it's own post. But first I'll have to see how well it works out.
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Old 12-05-2020, 03:44 PM   #8
Pat Thomson's Avatar
Trailer: Trillium Jubilee
Posts: 74
I don't think I have ever seen a Jubilee without brakes, so far as I know they were standard.

More pictures as you progress, please.

If you have structural sag it may happen on the sink side, like ours. The door side seems to be overall a better structural design.

What are you doing inside? You had the vile foam/popcorn, I presume.
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Old 12-05-2020, 05:45 PM   #9
Junior Member
Name: Michael
Trailer: Trillium Jubilee
Posts: 15
Axle mount

Thanks for the nudge to update the build thread. Here are some more photos in the hope that they may be helpful to others.

Seeing that the wheels were slightly forward in the wheel-wells, I had made cardboard templates of the available space indexed to the frame before removing the shell for future reference. The goal was to center the new spindle by moving the axle rearward to allow for the possibility of using 14" wheels/larger tires and clear the shell with the swing arm in compression.

Powder coating the frame meant that the axle had to be removable since the axle could not be oven-baked to cure the coating without damaging the torsion rubber springs. So a side-mount #10 Dexter axle was configured with a #2500 lb. load rating and specified width allowed the side-mount brackets to align with the INSIDE dimension of the tailer frame. These mated up to the new reinforcing plates welded into the frame. I also increased the height slightly with a 10 degree down-angle on the radius arm.

From the axle rearward the old bent frame was replaced with heavier 3/16" wall tube, and as the photos show, an additional angle crossmember under the floor step and tapered gussets to further support the cantilevered frame. The new axle brackets were wider than the frame so a piece of 1/2" bar was added on the outside to fully support of the axle.
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