To NWIP's point, some RV sway is "normal". You need to provide vehicle details, make, model, age, miles, condition. The driving conditions under which the vehicle sway is unacceptable. Without these details any recommendation is equivalent to throwing darts at potential mechanical adjustments.
Hi, First I'd like to say Thank you for welcoming to this forum. I just purchased a class C from my sister, which she and her husband did not use much. Its a 1994 Fleetwood, with 30,000 miles on it, 22-1/2' in lengh. It is a Ford 350 with the 460 engine and runs great, looks great and everything works as it should, except for the swaying. It is all stock, but it looks like he did replace the all shocks with Monroe Magnum 285. I have been looking at the sumo springs, but they need a gap or space, so i don't think the all the swaying will be eliminated with these. Not sure if I should change rear shocks and go to a heavier duty type..?
Any help with this will be appreciated, Thank You,
In my opinion, the first step is to determine if the suspension requires any repairs.
Worn bushings, rod ends, ball joints, broken parts, etc. If the suspension did not receive routine maintenance any one or more of the suspension parts could be causing issues.
If you have a truck suspension shop that you trust, you might have them take a look. I'd avoid a RV dealership unless they specialize in suspension repair.
Next step, after determining the suspension is working as designed, determine under what conditions you are getting unacceptable handling condition. Then address that condition.
Many people guess and just throw money at these problems, it gets expensive and frustrating. Suspensions look deceptively simple, however, vehicle handling is very complicated.
If you are in Florida, Josam in Orlando or Glenn's Tire in Melbourne might be good choices.
I agree with @Joe Goodxrvn first make sure all bushings and ball joints are in good order. What part of the country are you located, besides what Joe suggested maybe we can direct you to a reputable service facility.
Proper tire inflation.
Like the above posters front suspension could be a big issue. I would take it in for front end alignment. They will check the suspension parts before alignment and you will kill a couple dogs with one stop.