At this point, we have ground out the cracks, welded uphill with 7018, ground smooth and fishplated with 1/2" plate about 12" both ways from bend/cracks. We'd like to plate the inside also, but the crossmember there kind of makes that difficult. My opinion, the frame/tongue should have been made out of heavier channel to start with. When the trailer is tilted, the force on this part of the frame is a lot. Another design flaw I see, is when the trailer is tilted, the front tires are lifted completely off the ground. This isn't just a car hauler trailer, it's advertised for hauling tractors also.
As far as the leverage problem with the cylinder, what we've come up with so far is a piece of heavy square tubing, as a crossmember right in front of the smaller channel crossmember, behind the cylinder, with a square tubing stiff leg from it to the cylinder mounting plate. Does anyone see a better idea?
This trailer has been used so little, the deckplate doesn't even have the paint rubbed off of it anywhere. I don't know what was paid for this trailer, but one dealer I found that sells them, starts at about $6300.00 up to $7,000 for this trailer depending on length (18'-24')
I think designed and built right, this would be a great trailer... BUT I think the main frame should have the axles mounted to it, where all the tires would stay on the ground when tilted. I also think the frame should be constructed out of heavier channel. It is 6" channel, but very thin (for a trailer frame of this size). The tilt cylinder should have had more thought put into the mounting. The torque put on the crossmember by the cylinder is way too much.
I've not worked on smaller trailers like this much, my trailer experience has been on 35 and 50 ton lowboys, and 40' oilfield floats. I've never even owned a small trailer,except a single axle tilt we built to haul the lawnmower, so never really paid much attention to how they're constructed. After looking this one over, it's kind of scary thinking what people are pulling down the highway... This is considered to be a "premium" trailer, and it's not built that well at all I don't think.