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Posted by Jeff Wisnia on February 6, 2007, 1:44 pm
jeff37 wrote:
> So I noticed the other day that the pull cables on my extension spring
> garage door had fallen off of the pulleys (the ones vertically aligned
> with the door when its down) on both sides.
>
> I decided to start by replacing the cables. The pulleys all seem fine
> - they turn and are not bent in any way. I did this on one side, and
> I noticed the instructions sort of breezed over how tight you should
> make it (ie where to secure the other end of the pull string to the
> fixed position on the ceiling). I basically placed it such that, when
> the door was open, the cable would remain just taunt between the
> pulleys so that they would not sag.
>
> I then took a closer look at the side which I had yet to replace. I
> noticed that, when the door is fully opened, the wire sags severely
> between the pulleys. There is no chance it would stay on without any
> tension. Here are my questions:
> 1) While working, I had the garage door fully pulled up so that it was
> completely flat in the opened positoin (and braced with clamps). I
> can't remember for sure, but I assume that in normal operation it
> never goes up that far - it must stay down a bit where the last
> segment actually bends slightly. If this is the case, I think the
> cable has a better chance of staying in the pullys, but right now I
> don't even think my newly installed side would stay this way. So,
> does the pully system rely on the door never being completely
> horizontal?
It may not "rely" on that, but I can't recall seeing an overhead
sectional door where the bottom section ended up fully horizontal when "up".
>
> 2) Does the sagging indicate that my springs need to be replaced?
> They still seem to pull up the door when the pully remains on the
> track, so I assume they are OK.
>
> 3) What is the proper method for setting the tension of the pull cable
> in a resting position? I'm concerned about it being too loose and
> causing the cable to fall off the pulleys in the up position, or it
> being too tight and causing breakage of the springs in the down
> position.
>
> Thanks,
> jeff
>
I have always adjusted the spring tension by trial and error so that the
door's weight is just balanced when the door is raised half way up, and
it'll "hang" at that position without having to hold it. If the springs
are correctly sized to the weight of the door, that should do it.
Do you have "safety cables" running through the spring bores? If you
don't, do yourself and others a favor by picking up a set and installing
them. They cost less than ten bucks and it only takes a few minutes to
hook them up. The head you save could be your own if a spring decides to
snap and flail around whilst you're standing in the wrong spot.
Safety cables will help prevent the "spring sag" you mention as well as
any flopping about which might be what's causing the cables to flop off
the pulleys.
(another Jeff)
--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.
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