Why did my 2 post lift keep going and going and going...

[Joelk]

I have a Bendpak 9000 Lb 2 post lift that I have had for about 10 years(bought used) and it has worked very well for me, but...

I have 11' 4" ceiling and the tops of posts stick up through the rafters. It is a non issue with most cars and some smaller SUVs, but I have to use caution when lifting Pickups, Vans and larger SUVs.

A few days ago we had my Brother's GMC Terrain on it and took it up. I stopped at the next to the last "lock notch" because it seemed as close to the ceiling as I wanted to take it. I left it down to let it rest on the locks. After we drained the oil we lifted it up slightly to release the locks and then lowered it down to where we wanted for rotating tires and I again rested it on the locks.

After we rotated the tires I told my Brother to run it up enough to get the locks released. It started up and KEPT GOING UP EVEN AFTER HE TOOK HIS FINGER OFF OF THE BUTTON. He pushed the release lever and that slowed it's assent, but it did not stop until it was as high as the lift would go and the GMC was pushed up tight against the ceiling.

I went and threw the breaker while he continued to push the release lever.

Fortunately, this vehicle is only very slightly too tall and it does not appear to have damaged the vehicle or the ceiling, but if Fullsize P/U had been on it, I assume it would have damaged the roof of P/U and the ceiling.

I pulled the switch apart and it looked normal and tested normal with VOM. Reinstalled switch and while he stood with hand on breaker I slightly raised it(have to raise to release locks) and released the locks. After we got it off, I ran it up and down empty several times and it seemed to work fine.

It surprised me that use a small Micro Switch under the button. I have ordered a replacement and will install as soon as it arrives, but CAN I BE SURE THAT THE SWITCH IS THE CAUSE OF THE PROBLEM?

With a P/U on the lift a recurrance could be VERY expensive.

Is there anything else that might have caused it to keep lifting? Something in the motor? Or???

Any idea if there is an easy and SAFE way to increase the amount of fluid that is vented by the "release lever". If the fluid is relieved faster than it pumps, I could strap the release lever down and go to the breaker panel to flip the breaker, but I don't want it to zoom down when I push the release lever.

Any other suggestions(except for raising the ceiling) that would make me feel safe to use it with a tall vehicle on it.

 

[matt_i]

If you use a contactor instead of the pushbutton to run the motor it will eliminate that possibility. My guess is the contact got welded.

In an IEC or the larger more robust NEMA style contactor/motor starter will have contacts good for hundreds of thousands of hits at full amperage.

Use the micro switch to energize the coil which only requires milliamps.

 

[superduty1]

Some lifts I've seen have a safety bar at the top where if something hits it (roof of car or truck), the lift stops raising.

That sounds like a safety mechanism you need, just in case.

Sent from my SM-G973U using Tapatalk

 

[Moosefire]

I've also seen people run a disconnect at the lift just for that reason, this way if it happens you dont have to go to the breaker panel. Looks like this

Sent from my SM-N960U using Tapatalk

 

[dagofast]

Contacts can fail. It doesn't matter if they are in a microswitch or a heavy duty contactor. You need either an old fashioned disconnect in the incoming power or install a normally closed safety circuit, like an emergency stop mushroom button that opens the circuit from your push button.

Have I done any of the aforementioned on my lift? Nope. My lift runs on 20 amp 120V. If the push button ever fails, I can just reach up and pull the plug...

 

[finn]

Sounds like the op or previous owner eliminated the micro switch and overhead safety bar in order to fit the uprights between the bottom cord of the trusses. I assume the 9k lifts have the same setup as my 10k Bend pack

 

[2oolhound]

I had this happen on a battery powered fork lift. It was a solenoid that went on it.

 

[Mr_fixit]

I had a microswitch fail, so I added a 220v (dp) switch, then a couple years later the replacement failed. So I eliminated the microswitch, and added a pushbutton switch . now in emergency I can either flick the dp switch, or pull the 220 volt plug. There's some other ideas in the garage lift modifications thread.

 

[NitroShark]

I added a disconnect switch to both my BP 2 and 4 post. Doubles as a lock out / tag out as a bonus.

.

 

[xlowxyotax88x]

My old lift at work did this to me and at the time was only 2 years old it's a Challenger 10k. The relay inside the contacts welded together, we got them free and cleaned up and it did it again within days. We replaced it and it's been fine for the last 2 years. The lift in my current Bay at works is now approaching the 2 year mark so I'm waiting to see if this one does it as well(same lift)

 

[Joelk]

Thanks for the replies!

I got the "Safety Bar" with the lift, but did not install it, thinking that it would reduce lift height, even more than it is now. Not sure where it is at, probably in my attic.

Will the Safety Bar shut it off, even if the primary switch fails(contacts get welded)? I assume it would, but I don't like assuming.

I did some more messing around with the lift today and part of my original explanation was inaccurate. With the switch pushed/pump running and the release valve pushed, it DOES NOT GO UP. With me on lift arm it actually lowers.

When the incident happened I assumed some things from what my Brother told me. He said that he took his finger off of of the button and it kept going up and then he pushed the release valve. Apparently it was already at the top when he got around to pushing the release valve.

Knowing this makes me a lot more comfortable. At least I know that if I am paying attention and the switch fails I will be able to stop it from going on up, assuming I react quickly. I already have a ******** it that would hold the release valve down and allow me to get to the breaker panel and turn the breaker off.

 

[Mr_fixit]

Thanks for the replies!

I already have a ******** it that would hold the release valve down and allow me to get to the breaker panel and turn the breaker off.

That doesn't sound good enough

 

[jpaw]

Put the safety bar on it !!!!and make sure that it works and is below the ceiling height.
You may have to get creative with some sort of spacer to bring it below the ceiling if it is in the rafters.
That bar breaks the circuit when pushed.
You don't need to modify the lift other than possibly a spacer. Just assemble it as it was designed and you won't hurt anything or more importantly anyone.
This is why the manufacturer specifies a minimum ceiling height.

 

[Joelk]

put the safety bar on it !!!!and make sure that it works and is below the ceiling height.
You may have to get creative with some sort of spacer to bring it below the ceiling if it is in the rafters.
That bar breaks the circuit when pushed.
You don't need to modify the lift other than possibly a spacer. Just assemble it as it was designed and you won't hurt anything or more importantly anyone.
This is why the manufacturer specifies a minimum ceiling height.

WILL THE SAFETY BAR SWITCH STOP the LIFT FROM RISING EVEN if THE CONTACTS in the PRIMARY SWITCH GET WELDED TOGETHER?

 

[Barrymaxx]

I put a disconnect in arms reach of the lift button and I already had to use it once. My cheap *** bendpak button sticks often (Mechanically).

Someone on here gave me the idea and I am very thankful for that.

 

[kngelv]

You need a E-Stop or the disconnect within reach. I would also suggest an over travel switch.

James

 

[kbuhagiar]

This Is What You Need.

Period.

 

[jpaw]

WILL THE SAFETY BAR SWITCH STOP the LIFT FROM RISING EVEN if THE CONTACTS in the PRIMARY SWITCH GET WELDED TOGETHER?

Yes, it shuts the lift off as soon as it is pressed.

 

[Farmall450]

Man, that's scary. Sounds like you reacted the best you could. I'd agree on a deadman mounted on the post after than incident like that...cheap insurance.

 

[finn]

Man, that's scary. Sounds like you reacted the best you could. I'd agree on a deadman mounted on the post after than incident like that...cheap insurance.

Or else how about just not defeating the safeties engineered into the lift by the manufacturer?

 

[isb cornbinder]

Maybe you are powering your lift with Energizer batteries. They just keep going and going.

 

[Farmall450]

Or else how about just not defeating the safeties engineered into the lift by the manufacturer?

Apparently they did a little too much value engineering on that swtich.

 

[Joelk]

Yes, it shuts the lift off as soon as it is pressed.

Thanks!

As long as the vehicle does not hit the ceiling, I don't see why having it go up further than intended would hurt anything. If I install the "Safety Bar" is there some reason to use a separate disconnect switch?

 

[sberry]

Or else how about just not defeating the safeties engineered into the lift by the manufacturer?

I got a couple genius types, really,,, but I got to watch they don't defeat engineered safety features. I used to figure I was smart enough to outsmart them but come to find out lots of them very specifically designed, lots of forensics in long established models and types of equipment.
Lots of it simple, some stuff we never even considered. Wood furnace is a good example.

 

[jrkrace]

I just added a twist lock plug in line with the cord to the control box....simple and effective for me...

 

[kbuhagiar]

I just added a twist lock plug in line with the cord to the control box....simple and effective for me...

That works, too, so long as it is within easy reach.

 

[toplessHO]

mine has a small aircraft cable running at top of supports spanned between them.
Its attached to the control circuit

 

[Joelk]

mine has a small aircraft cable running at top of supports spanned between them.
Its attached to the control circuit

That sounds like a better arrangement than the safety bar and may be easier for me to mount. What lift do you have? Do you have any photos, especially photos of the switch?

Thanks, Joel

 

[jpaw]

I guess that I'm failing to understand your issue with the safety bar. I have used all different types of lifts over 25 years and have never had an issue with the safety bar unless it wasn't hooked up properly.
From your description it sounds like a vehicle will contact the ceiling before it can even touch the safety bar. You could simply use any type of tubing to hang off of the original bar to extend it to below the ceiling height effectively lowering the safety bar.

 

[Joelk]

I guess that I'm failing to understand your issue with the safety bar. I have used all different types of lifts over 25 years and have never had an issue with the safety bar unless it wasn't hooked up properly.
From your description it sounds like a vehicle will contact the ceiling before it can even touch the safety bar. You could simply use any type of tubing to hang off of the original bar to extend it to below the ceiling height effectively lowering the safety bar.

I do not have a Safety Bar installed. I got one with the lift 10 ish years ago, but don't know where it is at, or if I even still have it.

I like the concept of the cable/switch better than the Safety Bar/switch and think it may be easier for me to mount.

 

[jpaw]

Personally, I would find or acquire the correct safety for your lift and make adjustments to it as needed rather than to rig something up.
I mean you made it 10 years without one why start now. You're lucky you weren't alone when it happened otherwise you might not be here to ask these questions. I've seen cables break and vehicles fall off of lifts and it's not something that you want to experience.
But to each their own.
Just don't want to see anyone get injured or worse.

 

[toplessHO]

The lift was purchased off ebay many years ago
made in Texas and is labeled Team Lift.
It would be pretty easy to retrofit this system to any lift.
I had the lift custom made to my specs shortening a 12 ft column to 11'8"
As a result the cable system also had to be custom made.
The control is a switch thats mounted at the powerhead,which will break contact when the cable is moved.

Cable operated safety switches are very common in industrial applications,conveyors etc.
Find a switch and attach some eyelets to the columns,string 1/8" aircraft cable above and adjust until its on the ragged edge of tripping contacts.

 

[flyt100]

I put another switch in series that I hit at the same time to prevent the issue (had it stick once).