Liftmaster 3800 Installation

[nmk_61802]

I recently installed a Liftmaster 3800 on one of my garage doors. While testing, I noticed a slight wobble, or flex in the motor while the door is raising. It is almost unnoticable unless you are working on the motor an looking right at it. Liftmaster says this is incorrect, and that I should consult the installer, well, I am the installer.

What do you guys with 3800 say is this normal? To me the motor should have a little movement to it as it is resisting the torque which it is applying to the door to open it, hence the need for the mounting bracket. Which is what I believe I am seeing

 

[IDASHO]

They all flex a bit.

Normal, unless there is a lot of movement.

 

[heathy]

Mine does a bit at the initial start. I figured the torque being applied is causing it. It's only really mount to the wall at one point and the other is on the torsion bar you figure it going to flex a bit.

 

[mat_GTI-R]

i see this too... noticed this when the bottom bracket was not tight and will opening the door manually I can see the motor move... could it be a slightly bent torsion bar?

I cant even perform the adjustment step 1... I can set the open travel but door wont go down passed a few inches...

 

[SyTyJim]

i see this too... noticed this when the bottom bracket was not tight and will opening the door manually I can see the motor move... could it be a slightly bent torsion bar?

I cant even perform the adjustment step 1... I can set the open travel but door wont go down passed a few inches...

OK, check your black safety switch and make sure the cable that is suppose to run along it always keeping the swtich depressed. I had this problem and my door would only go down a few inches then open back up. Also, your lights should be blinking to notify you of a problem.

My problem was fixed when I had to 'bend' that cable a bit to keep pressure on the switch.

Jimmy