HP Netserver L Server series - Manual (Page 124)

Chapter 13 Alternative Rack Mounting (4–Post)
118
4. Match the outer-rail pins to the column holes (1st & 3rd) marked on the front
and rear columns. See Figure 13-3.
The mounting pins of the outer-rails should go into the inside face of the
rear column and front face of the front column.
Leveler
Screws (4)
Anti-tip Foot
Extended
Figure 13-4. Mounting Outer-Rails to Columns
5. With the outer-rails held in position at the rear, push in on the front
outer-rail mount.