What is the purpose of anti-skid surge accumulator in a 777-300?
When an aircraft touches the ground, brakes are applied to decelerate the aircraft. To execute this
on an efficient manner, an anti-skid system is installed. This makes it possible for the aircraft to perform
a stop with maximal deceleration and minimal wear of the tires. In this way the aircraft can
come to a safe stop without unnecessary maintenance.

Further info: https://anoukaviation.files.wordpress.com/2009/07/project-report-landing-gear.pdf (search for skid)

The anti-skid surge accumulator absorbs brake release surges from the left normal anti-skid valve module.
The right normal antiskid valve module does not need an antiskid surge accumulator because the right hydraulic system reservoir is very near to the right normal antiskid valve module.

From: http://www.plane.cc/html/ziliao/jiwu/2011/0426/23491_33.html