My 17-year-old Sears 1/2 HP chain-driven garage door opener has finally
given up the ghost. The motor runs but the plastic gear on the shaft
that meets the motor's worm gear has shredded itself. I think that
happened because the chain had become a bit loose and got caught in a
corner of its rail and caused the gear to become bound.
I called Sears to see about a replacement and they sell the entire
shaft and gear assembly for something like $35 plus shipping. However
removing the old shaft assembly doesn't look that simple and there are
more plastic gears attached to the bottom of the shaft that are
adjustments for the up/down distances. I suppose it could be done but
considering the age of the entire opener I am leaning towards buying a
Lowe's has a Chambelain 3/4 HP chain-driven opener for $157. After
speaking to the associate I realized everything must be changed,
including the chain and its rail system. Home Depot has a Genie 1/2 HP
screw-driven opener for $161.
My home repair skills are moderate and I am certainly no advanced
person, but I am an electronic technician and do have a wide assortment
of hand tools. I think I can do the installation although I don't know
how long it would take me.
What is your recommendation regarding the choices of openers and what
caveats should I be aware of if I choose to tackle this job myself?
Thanks for your thoughts.
Sears and others sometimes has a low cost install like 50 to 75
bucks, in my opinion its well worth the $$. A crew of 2 guys, amazing
how fast its in:)
The new opener will have sensors to reverse if anything walks in door
area, like a pet. Optical
I ike belt drive myself, very quiet:) Do get a touch pad for outside
mounting, its REALLY convenient. Indoor door open indicators are nice
They have openers that also turn on indoor lights so you dont enter a
All this safety and convenience is pretty cheap.
If you decide to DIY install you will need a helper to hold stuff
Do inspect your door, lube etc, check and install safety cables if
needed.Rollers do wear, That opener may have been working really hard
sometimes. Bearings and rollers wear out and may of never been lubed
since they were installed:(
Your old door probably needs attention too..... Might as well do this
Not a garage door, but a sheet vinyl floor. And 35 years ago, but the
big hardware store on Flatbush Avenue north of Prospect Park in
Brooklyn wanted 10 dollars to install the kitchen floor. Even though
I had little money, that seemed cheap even 35 years ago.
I'd taken everything out of the kitchen.
They delivered also for that price. A big floor that had to be folded
to go in the elevator. The room had 6 corners. The guy held it up,
looked at the room, and cut it in less than 2 minutes, and it was
between a quarter inch and 3 inches bigger than the floor all around.
Then he did a second cut that fit just under the baseboard, in another
two minutes. He was in and out in about 10 minutes. It would have
taken me 5 hours.
Allowing ten minutes travel time, they were actually taking in 30
dollars an hour, 20 minutes travel time gives 20 dollars an hour, so
they were probalby still making a profit.
I've installed at least 3 openers personally. But some stores quote $100 or
less for installation. I'd let them do it. Save yourself a day of
aggravation and 2 out 3 times the opener was missing one tiny part. Very
My 12 yo opener stripped the plastic gear saturday. 8 screws to get the
cover off (but you already have done that). 1 plastic clip at bottom of
shaft to allow the removal of the end gear. E clip at top of shaft (inside).
2 roll pins to be driven out with 8d nail and the stripped gear will slide
off the bottom of the shaft that you can now lift far enough to clear the
bottom plate. E-Bay part #41A2817 and as I did, pick up just the gear for
8.77+ $4 shipping. In the mail today should have by tomorrow or Wed.
I was surprised how easy it was to remove with common hand tools.
Good luck to you.
Okay, I have replaced the cog gear and greased up the system good. The
opener itself works and moves the chain back and forth. My problem is
the travel of the chain now.
I got it to where the door was moving fine up and down but it wouldn't
stay down when hitting the ground; it would come back up everytime.
After playing with the up/down travel adjustments now it's all messed
up and only travels short distances and puts a big bow in the rail when
it reaches the door. I have released the door from the chain for now
but have become tired of messing with it before I have to go to work.
It seems I must first get the travel distances correct then the forces.
What should I do next? Any suggestions on how to get the damn door to
Directions are on page 28-30 of the manual. Don't have a manual? Try this.
Adjustment Section: Pages 28 - 30
//limit adjust on the SIDE of the box//
Adjustment Step 1
Adjust the UP and DOWN Limits Do not make any limit adjustments until the
safety reversing sensors are completely installed.
Limit adjustment settings regulate the points at which the door will stop
when moving up or down.
The door will stop in the up direction if anything interferes with door
travel. The door will reverse in the down direction if anything interferes
with the door travel (including binding or unbalanced doors).
To operate the opener, press the Door Control push button. Run the opener
through a complete travel cycle.
o Does the door open and close completely?
o Does the door stay closed and not reverse
unintentionally when fully closed?
If your door passes both of these tests, no limit adjustments are necessary
unless the reversing test fails (See page 30).
Adjustment procedures are outlined below. Run the opener through a complete
travel cycle after each adjustment.
Repeated operation of the opener during adjustment procedures may cause the
motor to overheat and shut off. Simply wait 15 minutes and try again.
Read the procedures carefully before continuing on to Adjustment Step 2. Use
a screwdriver to make limit adjustments.
Improper adjustment of the travel limits will interfere with the proper
operation of the safety reverse system. The door might not reverse properly
when required and could seriously injure or kill someone under it. Test the
safety reverse system following all adjustments to the travel limits. See
Left Side Panel
How and When to Adjust the Limits
If the door does not open completely
but opens at least five feet:
Increase up travel. Turn the UP limit adjustment screw clockwise. One turn
equals 2" of travel.
NOTE: To prevent the trolley from hitting the cover protection bolt, keep a
minimum distance of 2-4" between the trolley and the bolt.
o If door does not open at least 5 feet:
Adjust the UP (open) force as explained in Adjustment Step 2.
o If the door does not close completely:
Increase down travel. Turn the DOWN limit adjustment screw counterclockwise.
One turn equals 2" of travel.
If door still won't close completely and the trolley bumps into the pulley
bracket (see page 4 or 5), try lengthening the door arm. (see page 26).
If you have adjusted the door arm to the maximum length and the door still
will not close completely, lower the header bracket. See Installation Step
1, pages 12 and 13.
o If the opener reverses in fully closed position:
Decrease down travel. Turn the DOWN limit adjustment screw clockwise. One
turn equals 2" of travel.
o If the door reverses when closing and
there is no visible interference to travel cycle:
If the opener lights are flashing, the Safety Reversing Sensors are either
not installed, misaligned, or obstructed. See Troubleshooting, page 23.
Test the door for binding: Pull the emergency release handle. Manually open
and close the door. If the door is binding, call for garage door service. If
the door is not binding or unbalanced, adjust the DOWN (dose) force. See
Adjustment Step 2.
Adjustment Step 2
Adjust the Force
//on the BACK of the box//
Force adjustment controls are located on the back panel of the opener. Force
adjustment settings regulate the amount of power required to open and close
The door will stop in the up direction if anything interferes with its
travel. The door will reverse in the down direction if anything interferes
with its travel (including binding or unbalanced doors).
If the forces are set too light, door travel may be interrupted by nuisance
reversals in the down direction and stops in the up direction. Weather
conditions can affect the door movement, so occasional adjustment may be
The maximum force adjustment range is 260 degrees, about 3/4 of a complete
turn. Do not force controls beyond that point. Turn force adjustment
controls with a screwdriver.
Too much force on the door will interfere with the proper operation of the
safety reverse system. The door might not reverse properly when required and
could seriously injure or kill someone under it. Do not increase the force
beyond the minimum amount required to close the door. Do not use the force
adjustments to compensate for a binding or sticking garage door. Test the
safety reverse system following all adjustments to force levels. See page
Back panel of door opener
How and When to Adjust the Forces
Test the DOWN (close) force
Grasp the door bottom when the door is about halfway through DOWN (close)
travel. The door should reverse. Reversal halfway through down travel does
not guarantee reversal on a two-inch obstruction. See page 30. If the door
is hard to hold or doesn't reverse, decrease the DOWN (close) force by
turning the control counterclockwise.
Make 10 degree turn adjustments until the door reverses normally. After each
adjustment, run the opener through a complete cycle.
Test the UP (open) force
Grasp the door bottom when the door is about halfway through UP (open)
travel. The door should stop. If the door is hard to hold or doesn't stop,
decrease UP (open) force by turning the control counterclockwise.
Make 10 degree turn adjustments until the door stops easily. After each
adjustment, run the opener through a complete travel cycle.
If the door doesn't open at least 5 feet
Increase UP (Open) force by turning the control clockwise. Make 10 degree
turn adjustments until door opens completely. Re-adjust the UP limit if
necessary. After each adjustment, run the opener through a complete travel
If the door reverses during the down (close) cycle and the opener lights
Increase DOWN (close) force by turning the control clockwise. Make 10 degree
turn adjustments until the door completes a close cycle. After each
adjustment, run the opener through a complete travel cycle. Do not increase
the force beyond the minimum amount required to close the door.
Adjustment Step 3
Test The Safety Reversing Sensor
o Press the remote control push button to open the
o Place the opener carton in the path of the door.
o Press the remote control push button to close the
door. The door will not move more than an inch,
and the opener light will flash.
Professional service is required if the opener closes the door when the
safety reversing sensor is obstructed.
The garage door opener will not close from a remote control if the indicator
light in either sensor is off (alerting you to the fact that the sensor is
misaligned or obstructed).
The garage door can be closed by pressing and holding the Door Control push
button until down travel is completed.
Without a properly working safety reversing sensor, persons (particularly
children) could be seriously injured or killed if trapped by a closing
garage door. Repeat this test once a month.
Adjustment Step 4
Test the Safety Reverse System
o Place a one-inch board (or a 2x4 laid flat) on the
floor, centered under the garage door.
o Operate the door in the down direction. The door
must reverse on striking the obstruction.
If the door stops on the obstruction, it is not traveling far enough in the
o Increase the DOWN limit by turning the DOWN
limit adjustment screw counterclockwise 1/4 turn.
o Repeat the test.
On a sectional door, make sure limit adjustments do not force the door arm
beyond a straight up and down position. See the illustration on page 26.
o When the door reverses on the one-inch board,
remove the obstruction and run the opener through
3 or 4 complete travel cycles to test adjustment.
If the door will not reverse after repeated adjustment attempts, call Sears
Service Center for garage door opener service.
Failure to test and adjust the safety reverse system may result in serious
injury or death to persons trapped by a closing garage door. Repeat this
test once a month and adjust as needed.
(One-Inch board (or a 2x4 laid flat)
Important safety check
Repeat Adjustment Steps 1,2 and 4 after:
o Each adjustment of door arm length, force controls
or limit controls.
o Any repair to or adjustment of the garage door
(including springs and hardware).
o Any repair to or buckling of the garage floor.
o Any repair to or adjustment of the opener.
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