Paccar air ride front axle. Bump steer?

My Volvo air ride did the same, on rollers, where the truck would get into a rhythm. You definitely need to keep fresh shocks on them, because there’s minimal friction in the suspension, compared to a leaf pack.

 

Clean your kingpins with brake cleaner . Check for play. Grease your spring bushings check for play.check for bearing play.paccar Air ride likes 4 to 5 degree positive caster. Make sure you have 1/16 toe in after setting the caster and ride height.check tires rims drag link and tie rod .check for Loose ubolts ,cracked air bag saddle ,Cracked air bag locks. Loose front cab mounting bolts and loose steer shaft firewal bushing can cause it too. Check for cracked springs close to the front leaf spring bushings. Leaking air leveling valves will change the caster and that will change the toe going down the road and will result in bump steer too. Get the after market leveling valves with thread on fittings if you have leaking factory leveling valves as they do start to leak .