Installation Guide
SALSBURY INDUSTRIES 
1010 East 62
nd
 Street, Los Angeles, CA 90001-1598 
 Ph: 1-800-624-5269   Int’l Ph: 323-846-6700 
 Fx: 1-800-624-5299   Int’l Fx: 323-846-6800 
 www.mailboxes.com    engineering@mailboxes.com 
Installation instructions are provided as general guidelines. It is advised that a professional installer be consulted. Salsbury Industries assumes no product assembly or installation liability. 
Copyright © 2017 Salsbury Industries. All rights reserved. (02/10/17) Page 1 of 2 
With its high quality design and construction, Salsbury’s 3900 series free-standing 4C horizontal mailboxes will provide years of maintenance free 
service. Please read this entire document before beginning installation. 
Installation Planning Notes 
1.  The  free-standing  4C  horizontal  mailbox  unit  has  been 
configured to meet the USPS height regulations. 
2.  The free-standing enclosure is shipped fully assembled with the 
exception  of  the  front  panel and  the  mailbox  unit,  which  are 
installed after the enclosure is fastened to the floor or concrete 
pad. 
3.  Determine the location of each of the 3900 series free-standing 
4C horizontal mailbox units. 
4.  If necessary, construct the concrete pad on which the 3900 free- 
standing 4C mailbox(es) will be mounted. 
5.  Due to the various mounting surfaces and subfloors to which the 
free-standing enclosure  may be  installed,  mounting fasteners 
are not supplied. 
6.  Select the appropriate anchors or  fasteners to attach the  free- 
standing enclosure to the floor or other surface to which it will be 
mounted. 
7.  Provide a means for leveling the enclosure, if necessary. 
Types of Fasteners Used 
Type A, Fig. 1 – To fasten the front panel into the enclosure, use the 
#10x1/2” pan head self-drilling sheet metal screw (supplied). 
Type B, Fig. 2a – To fasten the sides and the bottom of the mailbox 
unit  into  the  enclosure,  use  the  #8x3/4”  pan  head  self-tapping 
machine screw (supplied). 
Mounting the Free-Standing 4C Mailbox Unit 
to the Floor 
Place the outside enclosure into the selected position. Transfer mark 
the four (4) large hole locations in the horizontal bottom side flanges 
to  the  mounting  surface.    See  Fig.  3.    Remove  the  enclosure  and 
make the holes for the installation fasteners.   Install the installation 
fasteners. Position the rubber pads on the floor surface.  See Fig. 4. 
Return  the  enclosure  to  the  selected  position  on  top  of  the  rubber 
pads.  Lock the enclosure down by completing the installation of the 
fasteners. The use of leveling nuts on stud anchors is suggested. 
Installing the Front Panel 
Install the front panel at the lower end of the front of the enclosure. 
Use  Type  A  screws.    The  quantity  varies depending  on  the  height 
and width of the front panel. See Fig. 5. 
4C Free-Standing Horizontal Mailboxes–3900 Series 
Installation Instructions 
Fig. 1 
Fig. 5 
Type A 
1 
Fig. 2a 
Type B 
1 
Type A 
INSTALLATION 
FASTENERS 
(NOT SUPPLIED) 
LEVELING 
NUT 
Fig. 3 
Fig. 4 
RUBBER 
PAD 


