background image

Eight-Foot Rail Extension Kit

Models 7708CB and 7708CB-P

BEFORE YOU BEGIN:

•  The trolley must be in down (closed door) position during assembly 

and installation.

 If you have a completely installed garage door opener, 

the rail/opener assembly must be taken down. UP and DOWN Limits must 
be readjusted after installation. 

•  Opener hanging brackets will require repositioning and the addition of an 

extra bracket for stability due to increased rail length.

IF THIS IS A NEW INSTALLATION:

Use the  front (header) rail section, chain/cable assembly, and longer 
emergency release rope in this kit in place of those packaged with your 
garage door opener. Complete the assembly, installation, and adjustment of 
your opener according to your owner’s manual, with the exception of 
adding an additional hanging bracket for stability.

IF THIS IS AN EXISTING INSTALLATION, CONTINUE AS FOLLOWS:

1.   Pull down on the emergency release handle, then disconnect the trolley 

from the door arm.

2.   Disconnect the rail/opener assembly from the header bracket and 

hanging brackets, and place it on the floor.

3.   Remove the outer nut 

(Figure 1)

 from the trolley shaft and set aside.

4.   Disconnect the two master link assemblies from the trolley 

(Figure 1)

and discard. 

5.   Remove idler pulley assembly and set aside.
6.   Remove the chain/cable assembly and discard.
7.   Push the trolley back toward the opener. Disconnect the front rail 

section by using a screwdriver tip to pry up the outer tab on each 
side of the rail, then slide it off the center rail. Discard the front rail 

(Figure 2)

.

8.   Align the new front rail with the existing rail assembly, keeping the cut 

out “window” at the front (header) end. Be sure to keep it right side up: 
the idler pulley bolt hole above the window is larger on top of the rail 
than on the bottom. Slide the front rail onto the assembly; tabs along 
the side will lock into place.

9.   As a temporary stop, insert a screwdriver into the hole 10" (25 cm) 

from the front end of the rail 

(Figure 1)

. Slide the trolley assembly to 

this point.

10. Locate the rail tab.  Use a flathead screwdriver and lift the rail tab until 

the tab is vertical (90°) 

(Figure 2)

11.  Refer to your owner’s manual to complete the assembly, re-installation 

and adjustment of your opener. 

NOTE:

 

Before hanging the opener, an 

additional hanging bracket is necessary for stability. See Adding An 
Additional Hanging Bracket on reverse side. 

(Replace the old emergency 

release rope with the new, longer replacement rope.)

12.  Reconnect  power.
13. Make adjustments and test the safety reversal system according to the 

owner's manual. 

To prevent possible SERIOUS INJURY or DEATH:
•  Disconnect ALL electric and battery power BEFORE performing 

ANY service or maintenance.

Figure 1

Figure 2

The garage door MUST be in the fully closed position during 
installation.

To remove rail pry both 
end tabs of front 
rail slightly outward

Idler Bolt hole

(KEEP LARGER 
ONE ON TOP)

NEW
FRONT RAIL

CORRECT

INCORRECT

Rail Tab

Rail Tab

Threaded 
Shaft

Outer
Nut

Front Rail 
Section

Inner
Nut

Lock 
Washer

Master 
Link

Master 
Link

Master 
Link

Master 
Link

Idler Pulley

Trolley

WARNING:

 This product can expose you to chemicals including 

lead, which are known to the State of California to cause 
cancer or birth defects or other reproductive harm. For more 
information go to 

www.P65Warnings.ca.gov

Reviews: