Good stuff.

Off topic slightly, my old Komet trailer--steel tubing with aluminum skin and wood floor--had a doubler tube welded in alongside the lower longeron where the axle attached on each side. That weld between the doubler and the longeron eventually failed, allowing the axle mount on that side to push up, bulging the wood floor enough that the wing dolly wheel wobbled each time we brought out the wing. We initially thought it was just the wood floor warping after some years but discovered by crawling under the trailer and inspecting that the damage was more severe. Straightforward to fix: remove glider plus portions of the sidewall skin and floor, then drive it over to a welding shop to add reinforcement.

My Cobra has extruded side panels and an aluminum/foam floor. IIRC, the axle attaches via a short section of angle that acts as a doubler. Depending on the clearance, I've used a jack under that doubler and also under the pivot of the axle swing arm itself. I, too, use a short length of 2x4 to spread out the load if I'm jacking directly under the side panel where there's no crossmember.

It's important to note that if the trailer tongue is not fixed to the ball of the tow vehicle, jacking up one wheel can make the whole trailer somewhat unstable, even more so if the front dolly wheel--which is supporting the tongue--is partially extended and can swivel/roll. That's especially true if you're working on the brakes and therefore don't have the parking/emergency brake engaged. This is all hypothetical, of course; I've never had any close encounters with disaster.

Chip Bearden