An axle assembly having two hubs, each for connection to a wheel, a housing for differential gears and a mounting arrangement for a braking system for braking a connected wheel. The housing has a depression formed therein. The depression is configured so as to accommodate: (a) when the mounting arrangement has a drum brake mounted thereon, movement of a slack adjuster of the drum brake in a direction away from one of the hubs nearest the drum brake so as to allow detachment of the slack adjuster; and/or (b) when the mounting arrangement has a disc brake mounted thereon, an air chamber of the braking system, wherein the air chamber is capable of being partially accommodated within the depression.