Feeling a little sore today, yesterday I was under a 12000 pound Bendpak four post lift when the rear chain broke under the ramps. One air lock failed and it came crashing down. We had a 14 foot trailer on it that weighed between 4000 and 4500 pounds and were redoing the lights. I really feel luck to be here today.
** Lift Failure 4 Post
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mr55/56
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1955 210 two door post, six cylinder, three on a tree, Navajo Tan and India Ivory
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3,958 Posts
I don't have a lift. I depend on jacks, jack stands and wooden blocks. I always have a back up in place. While the car is on jackstands I slide a tire up under the frame. I skotch the wheels to keep them from rolling and use parking brakes or the drive train to keep it from rolling. I always put a wood block on top of the jack stand so there won't be metal-to-metal contact with the frame. My jackstands are tubular and use a through pin to set them, no harbor freight stuff. I still check the situation out before I slide under the car. You can't be too careful.
Interesting, I thought Bendpak was top of the line entertainment. Glad that it is not mine 12000 pound rating fails at 4500 pounds. I will never complain about having two mechanical locks on my two post again.
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17,533 Posts
I have an advantage four post. I am a scaredy cat. So I make sure the lift is sitting on all four mechanical locks before I get under the car. That being said, my days of being able to easily crawl under the car are pretty much done so that lift is a god send.
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6,696 Posts
I'd always thought the same thing about Benpak that they were rated one of the better lifts.I have a old western two post finally had to replace both cylinders a couple years ago after having both rebuilt 2 or three times in a couple year span seem good now but I've gotten where I let it down on the locks anytime I'm under it.Glad your Ok.Personally I always liked Rotary put about 20 in a dealership I worked at don't know they're quality now a days.
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19,459 Posts
I agree, always let it rest on the locks. If not, a sudden drop onto the lock COULD make the lock fail.
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13,021 Posts
Air pulls the safeties back when you drop the lift down basically. To operate, simply raise the lift from its parked position a few inches, push the pneumatic release button, and then press down and hold the lowering handle. The safety pins open via air. If a air cylinder in this case, sounds like two rear posts at the rear or car, didn't release and the safety stop wasn't engage. I assume that is way chain/cable broke as this was happening over time on those chains, or to much weight on that side (those two posts) as it was all resting on those two post at least the back. Glad he is ok.
Everyone with a lift needs to inspect lifts daily if in a large shop and at least 1-2 weeks at home. I always lower lift back on safety stops. Issues with air release is its hard to tell some times if is on the stops as the pins are in the posts. One way to check is to visually inspect stop pins are engage IE a walk around. Failures happen inspect your equipment and safeties, don't assume everything is working. I always rest my post on the stops. If not you're asking for trouble.
If this was at a business and I worked there I would be pissed at the owners for not inspecting their equipment. The issue with air locks is shown in if they fail the lift will fall. The mech locks one usually you can see the lock is engaged or you have to manually hold it back.
Thank you for sharing your story. I just went online and ordered 4 1500 lb stands.
Location:
North Alabama region, Tennessee River Valley
I'm not sure what an 'air lock' is, but I don't consider anything other than a strong mechanical STOP to be safe when I'm going under a lift with a car on it.. The tracks on a 4-post lift are nearly as heavy as a car by themselves, so even without a weight on the lift, it's still heavy enough to kill you if it were to fall.
WHAT is an air lock safety mechanism?? Can you or someone explain how that is Safe?
PS. I just read Bo185's explanation of the 'air lock', but it wasn't clear to me that such a lock is SAFE... Make sure your mechanical stops are in place and supporting the lift/vehicle BEFORE you get under it... (With the chinese lifts that most of us have, I even question the mechanical stops sometimes.. HOPING the metal is strong enough and won't fail...! )
WHAT is an air lock safety mechanism?? Can you or someone explain how that is Safe?
PS. I just read Bo185's explanation of the 'air lock', but it wasn't clear to me that such a lock is SAFE... Make sure your mechanical stops are in place and supporting the lift/vehicle BEFORE you get under it... (With the chinese lifts that most of us have, I even question the mechanical stops sometimes.. HOPING the metal is strong enough and won't fail...! )
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13,021 Posts
The air cylinder is not the lock persay its what releases the physical metal lock. So air moves the mechanical lock out from track. So ideally you release pressure and rack stop pins drop in track and release hydro pressure. Then you walk to each post and look at the pins are in. Or air cylinder is released if you can't see pin (depends on design). At the dealerships I been NO one I seen ever looked at the locks. Just put up release pressures and start working. I never trusted them so I would look at each on on the air locks. The other lifts had overhead track stops you could see them rest on the stops when letting pressure off.
This goes back to know how to use any piece of equipment you are using. Know the safety features were and how to use them. Read the actually manual vs someones word alone. As they may have been doing something wrong way and getting by for 40 years and then train you the wrong way or you maybe doing it wrong. This is not meant to hurt feelings or point anyone out its hopefully meant to save a life or someone else's in the worst or a bad injury in the least.
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3,049 Posts
Just glad you’re ok. Scary stuff! Ironically, jumping out of airplanes was integral to how I made my living most of my adult life. But lifts and jack stands scare me.
I think it’s because I watched a lot of Road Runner cartoons as a kid and can easily visualize how it could go wrong 😜.
Again- glad you’re able to warn us about it!
I think it’s because I watched a lot of Road Runner cartoons as a kid and can easily visualize how it could go wrong 😜.
Again- glad you’re able to warn us about it!
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10,412 Posts
Does this type of lift have a separate air supply just for the locks ?
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13,021 Posts
Yes the air powers the unock mech.
Some have on board air most need external air supply. Most you hook to shop air (an external air compressor). Some have tanks and "make" air when the lift moves up and down. But most are shop air powered.
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5,518 Posts
As with most machines, proper maintenance and procedures go a long way in preventing failures. I have 2, 4 posts lifts and a 2 post and all 3 of them have specific procedures that are similar but different. lowering the lift down to the locks and insuring those locks are fully engaged has been the "bible" in my shop for the exact reason mr 55/56 nearly ended his life. I see so many people raise a lift and just walk under it without confirming the locks are not just locked but fully engaged.
As far as the air locks, that is sort of a misnomer. They are actually air UN-locks. the locks are spring loaded and when the air is off the locks extend. on a four post it is common for the cables to get out of tension parity and you will have the decks not perfectly leveled or "Timed so as you raise it you here the locks clicking hit the last lock and when you lower it only 3 of the 4 engage and of those 3 one might only partially engage. Then if that last dog were to slip off, all heck breaks loose.
So as maintenance goes on the 4 posts it is important to confirm proper cable tension and timing, proper lubrication on the locks and all slides. and of course operation to a ritualistic level so as to never forget proper procedure.
As far as the air locks, that is sort of a misnomer. They are actually air UN-locks. the locks are spring loaded and when the air is off the locks extend. on a four post it is common for the cables to get out of tension parity and you will have the decks not perfectly leveled or "Timed so as you raise it you here the locks clicking hit the last lock and when you lower it only 3 of the 4 engage and of those 3 one might only partially engage. Then if that last dog were to slip off, all heck breaks loose.
So as maintenance goes on the 4 posts it is important to confirm proper cable tension and timing, proper lubrication on the locks and all slides. and of course operation to a ritualistic level so as to never forget proper procedure.
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1,489 Posts
we have a rotary 4 post at work. Its always dropped on the locks before going under it. i feel very safe under it, i think its a 14,000 lb lift, and we put some heavy Ram 5500's on it. I dont really get how a lift like that can fail if its dropped on the locks. If for some reason the shop air quits, you aint getting anything off this lift.
1957 Black Bel-Air Hardtop, Fuel injeted 350, 700r4 with Ford 9" Rear
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256 Posts
When I raise my Benpak I listen to see if all 4 locks are clicking at the same time when they hit each lock point and adjust them if they aren't. I always drop them back on the stops and check all the cables have tension on them before going under it.
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