Weight and cost: The 24-inch-long spring has a calculated weight of 8.4 lbs, not counting the winding cones. At less than $1/lb wholesale, and $3/lb retail for fabricated steel products, this spring should sell for about $8 to $25 (2005 prices) each, depending on the market and source. Since a pair is required, the expected cost for a pair is $16 to $50.
Removing winding cones from an old broken spring for reuse in a new spring: Springs without the winding cones installed are a little cheaper than with the cones. Twisting the old cones into a new spring is easy with a vise and pipe wrench, but it can be tricky removing old cones from a broken spring for reuse. To remove old cones, mount the cone in a vise such that the spring portion is free. Grab the last few turns of the spring in a pipe wrench, engaging the teeth of the wrench into the end of the spring wire. Turn the wrench against the end of the spring wire, releasing the end of the spring from its clamping onto the cone, as you twist the loosened spring off the cone. Another more certain if not brutal method is to use an angle grinder with a thin metal-cutting disk to cut through the loops of spring wire where the loops wrap around the cones, being careful not to nick the cone itself too much. You could also cut into the old spring loops with a just hacksaw and break off the loops with hand tools, but this will require a lot of effort.
For Sears Garage Door Installation and Repair Services, making your garage door safe is as important as making it function well. For this reason, all of our repair services and tune-ups feature a 20-point safety check. Our technician will carefully examine your garage door panels, springs, sensors, safety release, hardware, track, and more. This ensures that, not only has our work been done well, but that your garage door poses no danger to your vehicles or family. Due to the intricacy of garage door systems, only garage service professionals should attempt to adjust, repair, or service door equipment.
In the photo, you can see an extra lag screw on the bottom of the plate, reinforcing weak anchoring from the original two screws (hidden behind the springs). This extra screw was applied by a professional garage door technician on a previous repair visit. I have since replaced the backing with a sound plywood panel anchored into the concrete door header. Since these bolts clamp all the opposing torsion to the wall, the attachment must be sturdy.
The electronics should also be inspected before or after investing in the cost of replacing the garage door panel to make sure your door will operate properly. The sensors prevent the door from closing on someone's foot or a pet. If they don't work, someone could be injured. Also check to make sure the door opener works, since you could otherwise be locked out of your garage.
Roller doors ("Sheet Doors"-USA) are usually constructed of corrugated steel. They evolved from cover window and door coverings. Other materials can be used (e.g.; transparent corrugated fibreglass) where strong impact resistance is not required. Corrugations give the door strength against impacts. A typical single car garage roller door has a preloaded spring inside the rolling mechanism. The spring reduces the effort required to open the door. Larger roller doors in commercial premises are not sprung (except USA) and use a manual pulley and chain system or a geared motor to raise and lower (roll up and roll down) the door. Roller doors cannot be effectively insulated.
In my case, removing and replacing the relaxed springs required that I take down the assembly: torsion shaft, lift drums, and bearings. Doing that requires unbolting the center bearing plate from the wall, removing the drums from the shaft, and finally sliding the shaft back and forth out of the end bearings to remove the whole assembly off the wall. I am fortunate to have a lot of clearance in this garage to make the disassembly simpler. Tighter clearance to walls or ceiling would make disassembly a more difficult manipulation.
The prior clamping of the set-screws tends to have pressed a dimple into the hollow shaft and to have distorted the shaft's roundness into an eccentric shape. While releasing the set-screws, I was careful to loosen them enough to let the cone swing around any such distortions. I was also careful to observe any binding of the old cones on the eccentricity or burring on the shaft. The fit of the cone on the shaft is supposed to be loose enough to avoid binding, but if it were to occur one would have to be careful not to assume the spring was unwound when in fact the cone was just stuck on the shaft. If I had a stuck cone that I could not unwind with a little extra force, then I would have called in a technician to deal with it. In the worst case, I suppose the spring must be deliberately broken with some hazard, thus releasing it for a forceful disassembly, and the shaft and some other parts replaced. But this is an unlikely situation and in this case was not necessary.