To expand the topic slightly, Boeing state that with a L and L&C HYD SYSTEM(S) PRESSURE problem, that the speedbrakes have extended prior to using the R reverser.
The reason for this is that an incident occurred where a 757 lost the left hydraulic system, including the PTU, resulting in loss of nosewheel steering. After landing the crew selected the right reverser first. The yaw caused by a single engine reverse thrust was countered with the rudder. The 757 rudder is tall enough to cause roll which unloaded the wheels on the left side. The anti-skid sensed this and reduced brake pressure. The result was that the airplane departed the side of the runway at high speed. Selecting the speedbrakes first ensures that the maximum weight is on the wheels. This increases the braking force which is more effective than the reverse thrust as well as helps keep the wheels more equally loaded.