Fred,
Most of your questions will be answered here :
http://www.trilliumrv.com/parts.htm
My original frame had the modification done but cracked anyway. After 33 or 29 years you are done for a new frame and suspension. Do it right the firs time.
The shell is bolted with four 6 inches (or so) carriage bolts one in each corner. You can see them in each corner.
You raise the shell easily with a jack.
See above as far as reinforcing is concerned. But I don't recommend it for a 30 years old
Trillium.
Personally I just had a new frame done after a tough ride in Mexico ("toppe" pot holes and other torture instruments!).
I used grade 11 steel tubing which is one grade stronger than the one used for brand new Trillium (grade 12). The original frame was made out of 13-14 grade heated and stamped steel. No problem with
Weight distribution hitches when upgraded like this. The frame will be twice stronger than the original one.
I moved the location and the attachment of of the carriage bolts in order to avoid to make hole in the new frame. A small plate was welded on the side of the frame and bolt attached through it.
I made my new frame based on the new design. There is nothing now heated, stamped or bent. See :
http://www.trilliumtrailers.com/outback.php
There are many photos showing the front end of the frame. This is the only major change done to the original frame.
By the way I had my front end 1 foot longer as I wanted enough space for both my
generator and a future WDH. I didn't change anything to tracking. The tongue
weight will most probably reach 250 lbs.
I also changed the
axle. When you redo the frame, redo the suspension. As I said after 33 years, there is no abuse in rebuilding all this.
Here are the specs of my new axle.
Flexiride (make)
3500 lbs axle. Yes stronger than recommended but...
Rubbers are shortened and downsized to 2500 lbs in order to have a smoother ride (it does!)
10 inches electric drum
brakes
Trailing Arm minus 22.5 ° Starting Angle
48" OS Brackets
65" Track
Tapered Spindle
5 x 4.5 Hubs
I've done it with a 22.5 starting angle (recommended as the best by Flexiride) as I wanted the frame a little higher for two reasons (1.8 inches). After 5 years the suspension will lower anyway by may be a couple of inches and I wanted to have a little more clearance as I sometimes go on gravel and rough roads. Make a search on Flexiride on this forum and you will get more infos. Flexiride axles ARE adjustable.This is a big long term advantage. Dexter is NOT adjustable. Flexiride is a little more expensive than Dexter. If you think it is too much, lower it to 0 or minus 15 degrees. You can even get more clearance by going to -35-45 degrees!
As done, the Trillium roll perfectly well. is not too high. Smooth ride, perfect tracking. This added about 150-175 pounds to the trailer. But this is a close as you can go if you don't want a tank! :-)
All this costed me 1,500 CDN$. A very good investment.