Leaf Spring Failure - Replace the Others?

Since OP has a broken spring, he also has an equalizer. If it’s doing its job the wheel weights on the same side will be very close if not the same. A bigger problem in trailers is one side weighing more than the other. The CAT scales that I have used have curbing that doesn’t allow side to side weighing, but I’ve had individual wheel weighing done at an RV rally. That showed that the wheels on the same side were equal or within 50 lbs. But, it also showed that the heavy side (often the appliance side) was 950 lbs. more than the light side. Worse yet, it showed the heavy side to be overloaded for the springs and hubs. We moved some stuff around and started carrying less fresh water (the fresh tank runs front to rear on the heavy side—great design!) and shifted the difference to 750 lbs. now a little below the suspension rating. I was able to verify the improvement by finding a grain elevator scale where I could weigh with one side on the scale with the other side off.