Liftmaster 8500 pusher spring sizing

[AA7483]

I have a 9' hight door with a low clearance track. I installed an 8500 on it a few years ago. Ive been having issues with the cable tension monitor when the door first starts closing so i want to get a set of pusher springs to help things along. I've read that 9" springs should work in the application. What do you guys think?

 

[dante2]

I had a similar issue with mine having to help it to close or it would reverse back open. Finally got tired of messing with it and reset the up/down travel. My opener now works like it's supposed to. Something to try if you haven't done it yet.

 

[428PI]

I had trouble with my 9x7 door and the 8500. Got a set of the shorter pusher springs and they work fine. I had to shim up my cable tension sensor so it doesn't work. Was always giving problems. Perhaps If I had gotten the longer pusher springs the sensor would have worked. It seems that the speed changes just when the springs no longer pushing on door causing slight looseness on cables. I just measured my pushers and they're more like 6 inches of travel. If 9 inches is the actual amount of travel I believe they would work fine. I'm seriously thinking of using the 8500 on a 14x12 door but will go with angled up track to put weight onto cables.

 

[Viper98912]

Can you move the cable tension monitor upward a little bit so its a little more open? (assuming yours is like mine, where the angle of the cable becomes just a little wider away from the wall as it approaches the drum)

 

[AA7483]

Other than it tripping on safety all the time I don't want to have issues w/ the cable slipping off the drum. I've read that 9" is sufficient for this application. I was going to go bigger but I wont want to wear our the components.

 

[dante2]

I tried some pusher springs on my door thinking that would fix my issue but didn't help me. This is the style I bought. I had to fab a bracket to make them work on my tracks.

 

[racecougar]

Are the tracks slanted toward the opening at all? If they are set level, I'd suggest raising the ends a bit. Let gravity work for you.

 

[Viper98912]

I tried some pusher springs on my door thinking that would fix my issue but didn't help me. This is the style I bought. I had to fab a bracket to make them work on my tracks.

I had also bought a pair of pusher springs thinking the same, and the things didn't even line up with my door; they were too tall above the door. Ended up not using them.

 

[eegger]

Menards

I bought these for my 9x8, I still need to slant my track a little and it should be good to go. I am going to try and move the track up one hole and see if it is more consistent.

 

[CraigStu]

I never thought of pusher springs on mine. I also couldn't get a reliable up travel stop set in the programming so I finally made a physical stop on each track. The problem w/ mine was the original installer had the door running so far up it was pulling the cable end away from the wall and bottom edge of the door was only hanging down about an inch from the entire door being horizontal. I found that setting my stops so the bottom edge of the door was hanging down about 6 inches fixed the problem. Thinking back I should have raised the top end of the tracks a foot or so which would really help. The trouble w/ this entire design is that nothing but gravity closes the door. So if that motor turns the pulley just a little too fast, before gravity gets the door moving, you are lucky if the sensor shuts it down so you don't need to re-wrap the cable. If you have a lift in line w/ the door so need the clearance, these openers can be a life saver. Otherwise I see no advantage compared to the old style w/ whatever is the quietest drive type.

 

[racecougar]

They work well in situations with ceilings that are much taller than the door heights as well. Certainly a much "cleaner" solution than a standard operator in arrangements like this, IMO.

 

[Low Definition]

When I put my door in with an 8500 opener, I added cable keepers to the bottom to keep tension on the cable: https://ddmgaragedoors.com/parts/part/BF-CK.html

 

[73project]

Are the tracks slanted toward the opening at all? If they are set level, I'd suggest raising the ends a bit. Let gravity work for you.

I agree with slanting of the tracks. My door, when fully open, was exactly level with the ground. I could unhook everything and the door wouldn't fall down, so releasing the tension on the cables wasn't going to lower the door. I could of put some pusher springs on the door, but I felt that these were way more expensive than they should be ($97). I loosened the connecting hardware where the curved and straight tracks met, then angled the upper tracks at about a 8 degree towards the door, and the opener works like a champ. If all of the panels on your door are level, it's not going to fall down, which is what this style of opener relies on.

 

[AA7483]

The track is very close to the ceiling to begin with so I dont know how much I can actually get away with raising it.

 

[AA7483]

The bubble on the level was within the line but favoring leaning away from the door. I raised it one hole. Still within the lines but now touching the line favoring way I want it to lean.
Still not enough. Same problem. I could raise if more but I need to cut the angle iron.

 

[dfiler2]

I would try clamping a little weight to the bottom of the door and see if that solves the problem, if that works at least you would know that raising the track or loosening the spring would accomplish what you want.

 

[428PI]

or loosening the spring would accomplish what you want

Spring tension doesn't have anything to do with it. There has to be door weight on the cables. I tried to secure a brake rotor on the bottom of door but didn't really help. Solved all problems by getting pusher springs and doing away with cable tension sensor. I couldn't angle my tracks up much either as it was hugging the ceiling. I had only a 12 inch radius rail too. I think a 15 inch radius rail would help as the lower section of door could be lower and make the transition smoother. The problem I see is that the 8500 starts out slow and switches to a faster speed. It's in the transition to faster speed that some cable slack can happen.

 

[AA7483]

Spring tension doesn't have anything to do with it. There has to be door weight on the cables. I tried to secure a brake rotor on the bottom of door but didn't really help. Solved all problems by getting pusher springs and doing away with cable tension sensor. I couldn't angle my tracks up much either as it was hugging the ceiling. I had only a 12 inch radius rail too. I think a 15 inch radius rail would help as the lower section of door could be lower and make the transition smoother. The problem I see is that the 8500 starts out slow and switches to a faster speed. It's in the transition to faster speed that some cable slack can happen.

So what size springs did you use? Would I be safe w/ 9 inch springs on my 9 x 12 door?

 

[428PI]

So what size springs did you use? Would I be safe w/ 9 inch springs on my 9 x 12 door?

Here's some pics of my setup. If I remember they were the shorter springs. On my 14x12 ft door I'm going to angle the tracks as much as I can and don't run the door so high and see if it will work without springs.

 

[frankd]

Are the tracks slanted toward the opening at all? If they are set level, I'd suggest raising the ends a bit. Let gravity work for you.

I had the same issue and the above worked even without the pusher springs. I raised up the back part of the track. I don't recall how much...maybe 2 inches. That alone fixed the problem 95% of the time but it would still trip the safety on rare occasion so I added 9 inch pusher springs. DDM Garage doors is a great resource.