I have a Craftsman 1/2 hp screw-drive garage door opener. It was
professionally installed in 2003 on a new garage door. Never had a
bit of trouble with it (until now).

In the middle of January, my wife said "the garage door isn't closing
all the way". Sure enough, it stopped about 3-4 inches short of
closing. And, the arm mechanism would bang into the actual drive
housing when it was fully opened.

"Ah, simple adjustment" I thought. I grabbed a screwdriver and
adjusted the travel limits (lower and upper) and it worked fine. For
about two weeks.

I noticed was, again, not closing completely and banging into the
drive housing when opened. I adjusted the limits a second time.
Looked good to me.

Three days later... I notice it's not closing all the way grrrrr...

The problem is happening more frequently. Obviously, my feeble
attempts at adjusting the limits work only temporarily.

Could the opening arm be consistently 'skipping' on the screw drive?
What else could cause the repeating adjustment problems? Anything I
should check before I just call someone to take a look at it?

Thanks!

Sounds like the gear on the limit assembly is stripping out (odd for a
fairly new opener, but not on older ones) & that the assembly needs to
be replaced.

Doordoc
www.ActionDoor.com

On Jan 31, 11:40 am, "CsB" wrote:
I have a Craftsman 1/2 hp screw-drivegaragedooropener. It was
professionally installed in 2003 on a newgaragedoor. Never had a
bit of trouble with it (until now).

In the middle of January, my wife said "thegaragedoorisn't closing
all the way". Sure enough, it stopped about 3-4 inches short of
closing. And, the arm mechanism would bang into the actual drive
housing when it was fully opened.

"Ah, simple adjustment" I thought. I grabbed a screwdriver and
adjusted the travel limits (lower and upper) and it worked fine. For
about two weeks.

I noticed was, again, not closing completely and banging into the
drive housing when opened. I adjusted the limits a second time.
Looked good to me.

Three days later... I notice it's not closing all the way grrrrr...

The problem is happening more frequently. Obviously, my feeble
attempts at adjusting the limits work only temporarily.

Could the opening arm be consistently 'skipping' on the screw drive?
What else could cause the repeating adjustment problems? Anything I
should check before I just call someone to take a look at it?

Thanks!

"CsB" wrote in message
oups.com...
I have a Craftsman 1/2 hp screw-drive garage door opener. It was
professionally installed in 2003 on a new garage door. Never had a
bit of trouble with it (until now).


Check if the door is properly balanced. Disconnect it from the opener, and
pull it half-way down. Let go. Does it stay there? If so, it's properly
balanced. If not, the springs require adjustment, best done by garage door
techs.

My guess is that it is unbalanced & wants to go up, so the opener has to
push harder to get it to go down.

Or, do all the rollers roll properly in the track? Maybe some are dragging.

On Jan 31, 11:40 am, "CsB" wrote:
I have a Craftsman 1/2 hp screw-drive garage door opener. It was
professionally installed in 2003 on a new garage door. Never had a
bit of trouble with it (until now).

In the middle of January, my wife said "the garage door isn't closing
all the way". Sure enough, it stopped about 3-4 inches short of
closing. And, the arm mechanism would bang into the actual drive
housing when it was fully opened.

"Ah, simple adjustment" I thought. I grabbed a screwdriver and
adjusted the travel limits (lower and upper) and it worked fine. For
about two weeks.

I noticed was, again, not closing completely and banging into the
drive housing when opened. I adjusted the limits a second time.
Looked good to me.

Three days later... I notice it's not closing all the way grrrrr...

The problem is happening more frequently. Obviously, my feeble
attempts at adjusting the limits work only temporarily.

Could the opening arm be consistently 'skipping' on the screw drive?
What else could cause the repeating adjustment problems? Anything I
should check before I just call someone to take a look at it?

Thanks!

Mark the position of your limit screws and see if vibration is causing
them to turn on their own.

Well, I guess they wouldn't really be turning "on their own" if
vibration was causing them to turn, but you know what I mean.
Actually, if they WERE turning on their own that would be pretty
scary! g

DerbyDad03 wrote:

On Jan 31, 11:40 am, "CsB" wrote:

I have a Craftsman 1/2 hp screw-drive garage door opener. It was
professionally installed in 2003 on a new garage door. Never had a
bit of trouble with it (until now).

In the middle of January, my wife said "the garage door isn't closing
all the way". Sure enough, it stopped about 3-4 inches short of
closing. And, the arm mechanism would bang into the actual drive
housing when it was fully opened.

"Ah, simple adjustment" I thought. I grabbed a screwdriver and
adjusted the travel limits (lower and upper) and it worked fine. For
about two weeks.

I noticed was, again, not closing completely and banging into the
drive housing when opened. I adjusted the limits a second time.
Looked good to me.

Three days later... I notice it's not closing all the way grrrrr...

The problem is happening more frequently. Obviously, my feeble
attempts at adjusting the limits work only temporarily.

Could the opening arm be consistently 'skipping' on the screw drive?
What else could cause the repeating adjustment problems? Anything I
should check before I just call someone to take a look at it?

Thanks!


Mark the position of your limit screws and see if vibration is causing
them to turn on their own.

Well, I guess they wouldn't really be turning "on their own" if
vibration was causing them to turn, but you know what I mean.
Actually, if they WERE turning on their own that would be pretty
scary! g

Hi,
Switches are spring loaded. Some times spring breaks.

When it goes out of "alignment" it seems to stop about the same
distance from the ground (3-4 inches) each time. The first thing I
thought was maybe the arm was slipping along the drive shaft
somewhere. I didn't think about the gearing stripping.

Can I just pop the housing off of this model to check this? Or, is it
a more invasive procedure to get to these gears?


On Jan 31, 1:07 pm, " wrote:
Sounds like the gear on the limit assembly is stripping out (odd for a
fairly new opener, but not on older ones) & that the assembly needs to
be replaced.

I will do this tonight and report back with the results. Thank you.

On Jan 31, 3:51 pm, "Joseph Meehan"
wrote:
I would also check to make sure the door is properly balanced and is not
binding. Disconnect it from the opener and make sure it will open and close
without binding and that it will stay fully closed and fully open without
assistance.

I'll check this tonight and report back. Thank you.

On Jan 31, 7:11 pm, "Bob M." wrote:
Disconnect it from the opener, and
pull it half-way down. Let go. Does it stay there?

My guess is that it is unbalanced & wants to go up, so the opener has to
push harder to get it to go down.

Or, do all the rollers roll properly in the track? Maybe some are dragging.

I understand. I wondered this, also. The limit screws are fairly
stiff and I need to adjust them almost the exact amount of turns each
time (2+ turns). I'll look more closely and mark their positions to
see if vibrations are causing the trouble.

On Jan 31, 7:37 pm, "DerbyDad03" wrote:
Mark the position of your limit screws and see if vibration is causing
them to turn on their own.

http://www.liftmaster.com/pdfdocs/114A3077.pdf
Look on page 34 which shows the limit assembly (all the models are the
same).

Vibration isn't going to cause them to move that much. As I stated
earlier something is stripped or it may be the limit contacts are not
snapped onto the threaded screws completely.

Doordoc
www.ActionDoor.com

On Feb 1, 7:46 am, "CsB" wrote:
I understand. I wondered this, also. The limit screws are fairly
stiff and I need to adjust them almost the exact amount of turns each
time (2+ turns). I'll look more closely and mark their positions to
see if vibrations are causing the trouble.

On Jan 31, 7:37 pm, "DerbyDad03" wrote:



Mark the position of your limit screws and see if vibration is causing
them to turn on their own.- Hide quoted text -

- Show quoted text -

Another thought, the "rack" part #4 of the rail assembly on page 33
may be stripping & getting out of position on the screw, which would
throw the limits off. If it changes suddenly I would suspect this part
would be the problem more then the limits. If the limits are moving it
would probably be a gradual change.

DoorDoc
www.ActionDoor.com

On Feb 1, 11:00 am, " wrote:
http://www.liftmaster.com/pdfdocs/114A3077.pdf
Look on page 34 which shows the limit assembly (all the models are the
same).

Vibration isn't going to cause them to move that much. As I stated
earlier something is stripped or it may be the limit contacts are not
snapped onto the threaded screws completely.

Doordocwww.ActionDoor.com

On Feb 1, 7:46 am, "CsB" wrote:



I understand. I wondered this, also. The limit screws are fairly
stiff and I need to adjust them almost the exact amount of turns each
time (2+ turns). I'll look more closely and mark their positions to
see if vibrations are causing the trouble.

On Jan 31, 7:37 pm, "DerbyDad03" wrote:

Mark the position of your limit screws and see if vibration is causing
them to turn on their own.- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

Thank you for everyone that offered ideas. Here's what I figured out.

My garage door opener is a Craftsman Model 139.53992 €“ ½ hp screw-
drive.

I disengaged the trolley latch from the screw drive and tested the
door. It moved freely without binding. It would stay fully closed
and opened without assistance. If I opened the door 1/2 way up and
let go, it did pull back to the closed position. If I opened the door
2/3 the way up it would balance and stay stationary.

I then disassembled the housing to look at the mechanics. As a future
note to others disassembling this opener, to take the housing off
you: (1) Open the light lens. (2) Remove bulbs. (3) Remove the two
screws holding the cover to the bracket €“ these are in the upper
corners of the bulb area. (4) Pull the cover *forward* (toward the
lens) and remove. If you pull it downwards, youll brake the tabs on
the rear plastic piece (like I did). It just wouldnt be a home job
if I couldnt use duct tape in the repair. Check that one off. �

I was surprised at how simple the mechanism was. There are two gears
on the motor. The first is a gear that engages a belt which then
drives the screw. The second is a worm gear that engages the limit
switch assembly.

I immediately noticed the gear on the limit switch assembly was barely
engaging the worm gear on the motor shaft. I could gently apply
pressure to the limit assembly gear and it would €œjump€� downwards and
turn. Neither gear looked to be stripped or worn. However, both
gears were dry as a bone.

I also noticed if I applied very gentle pressure to the bottom of the
assembly (pushing upwards) the gear would fully engage. I removed the
assembly and cut a slim cardboard shim (from a 9v battery package).
There are three holes in the main bracket where the limit assembly
€œclicks€� into place. I put the shim in the bottom most hole and
inserted the limit assembly back into the bracket. The gear now fully
engaged and I could not force it to €œjump€� down and turn.

I didnt have any heavy grease, so I grabbed a tube of silicone and
lubed up the friction points on the limit assembly and where the
assembly engages the worm gear on the drive motor. I hope this wasnt
a mistake. Is regular silicone compound OK to use in a situation like
this? The door opened this morning (8+ hours after repair).

I appreciate everyones help and advice. Hopefully this will save
someone else a repair call in the future. If it ends up this is not
the fix, Ill post an update.

Thanks!