does a rear air pump have to be replaced
if it is the load leveler pump then you might want to just to keep everything all stable but its not a huge deal
As noted above, if you have a pump, then your car has rear load leveling. Your problem might be as simple as the rubber mounts for the pump have failed and the noise is transmitted into the car. The pump can be unplugged but the rear of your cars will slowly settle and look like it needs new springs. If you choose not to fix the pump, and you disconnect it, you probably should change to standard rear shocks....if that model of Lesabre has rear struts, it would be cheaper to fix the pump.
Search Buick LeSabre Questions
Buick LeSabre Experts