I used a torch on the spring/axle Ubolts because I replaced the tie plate, but I didn't want to use a torch on the other bolts because I didn't want to rish blistering / burning off the galvanized coating on the trailer frame.
I broke a spring last month. Took out a tire, and almost messed up my fender. Your springs definitely look to have been due for a change out. Funny thing I took care of the springs with oil and grease, and there was little little rust. Four years was to much service time on them. Thinking of going to a torsion spring axle next year.
I bought a used boat from Superstore had a bad spring all tilted over and forlorn. Paid and left. Came backwith my helper , Cranked the front down, put some jackstands under the back. Cranked the front back up Lifted the wheels up fired up my compressor and pulled the wheels and used the cuttoff wheel on the diegrinder to cut the bolts.Swapped enverything and while I was doing that , my helper hit the boat with some wd40.
Pulled out of the parking lot with a great looking boat. ****ed off salesmen could of got more $
spent a week doing all that replacement on a tandem trailer that didnt quite make it home from point of purchase. pain in the rear but the education acquired on used boat purchase and what to look for was priceless.
I just lost a wheel on my tandem trailer. Ended up replacing all four hubs,bearings,seals,etc. Springs, boards,carpet and hardware next week. While driving to get parts, saw 3 others boat trailers with bearing problems on the side of the road!!