97 expedition lft rear lower then rt??

the rear fell .. changed airbag, compressor switch & compressor... now left side is lower then rite side ... what else is left??? thx

they may have gave you a 2wd air bag if your Exped is a 4x4 , also, if its the right height airbag, and yours is a 97 , the age of the rubber might be letting it strecth alittle when its aired up, if its the sagging side