Now that we’ve introduced elevator pits and mentioned hydraulic jacks, we thought we’d share the story behind replacing one. Normally jacks, which are large pistons, given that they’re just a couple pieces of steel, last indefinitely. The seals need to be replaced periodically, but the metal parts live on and on for decades.
The main reason you’d need to replace one is that it’s buried in the ground and the exterior cylinder rusts out, allowing the oil to leak. If this happens, the elevator could drop suddenly and you also could create an environmental mess. Think Exxon Valdez, albeit on a much smaller scale. The Valdez had a single hull, and after its crash, double-hulled tankers became the norm, as a protection against another catastrophe.
Similarly, elevator jacks used to be manufactured with a single wall casing. In 1978 or so, they went to double walls, and later it became standard to encase the whole thing in PVC. So if you sink a jack into the ground now, it will never rust out. But if you’ve got one of the old ones, it just might.
We recently did a modernization on a 50-year-old elevator in a local bank. The state required that when we do the modernization we also replace the in-ground jack, even though there was no indication that it was yet leaking.
So our bull gang came in, jackhammered the pit concrete around the cylinder, and pulled out the piston. It was about 24 feet long, so we had to chop it into 3 pieces so it would fit out the door. Then we hoisted up the cylinder, chopped it into 3 sections, and sent it out the door as well.
Then we examined the hole. The jack had been set directly into the sandy hole, so when we removed it, the walls of the hole collapsed. Nowadays, new jack holes have a casing to prevent collapse, so we brought in specialty drillers to give us a clean, modern, cased hole. They pounded 5 foot sections of steel casing into the hole, welding sections together, until the entire hole was solid.
They then drilled the sand and muck out of the hole. Work then moved back to us, to install the new jack. First a PVC liner was sunk in the hole for permanent water protection, again in 2 pieces so it fit through the doors. We let it set overnight to make sure there were no leaks in the glue.
Then we installed the cylinder. The most critical step is plumbing the jack so that it lifts the elevator up without wearing on one side of the piston. This is done with a simple tool called a spider: a flashlight on the end of a string, dropped down to the bottom of a cylinder, where you can tell by the light it casts when the cylinder is perfectly plumb.
Once the plumbed-up cylinder was bolted down, we dropped in the piston, again in 2 pieces that screwed together. We poured concrete back in around the new jack assembly, to cement it into place, never to move again for 100 years.
So that’s how you replace an in-ground jack. Lots of elbow grease and regular grease and grime to make it happen.
did you use union gard 160 in the casing?
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We are in the process of having our jack replaced. The hole now has approximately 18 feet of sand, rocks and debris that a normal (All Centex) truck cannot suck out. What companies can remove the heavy debris? We are in central TX. Found a company in California, but nothing in Texas. Any help is appreciated!
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We have lots of friends in Texas that check in frequently. I will email a couple and see if they can help. Also, does the elevator technician have any ideas?
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Good day. In 2005 I was the owner and manager of Typhoon drilling. I had 20 years of experience in the elevator trade at the time starting with Otis and IUEC local 10. Eventually I spent many years with AMCO Elevator out of Indy as service mechanic. I saw a need for a more efficient way of installing steel casings and designed and built a drill for existing hoistways. My drill far exceeded my expectations. Three holes were cased and then divorce happens. I shut the doors on Typhoon drilling. I have all equipment sitting idle and it kills me to think of all the revenew this dill could be producing. I am interested in what possibilities might lie. My name is Jim Anderson @ 217 251 3886
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Hello. Wondering how long the replacement took to perform? Thanks
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The total time for the jack replacement was a week, but in this case the hole did not have to be re-drilled.
They can take several weeks to coordinate especially if a drilling rig is needed and a new liner is required.
Thanks for the great question.
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Condo board president here. We just got the notification that our jack failed. Thanks for posting the information. I also found this article very helpful:
https://www.elevatorlab.com/blog/hydraulic-elevator-jack-replacements-a-buyers-guide-to-improve-cost
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What was the cost of the job?
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It has been a while since the project was finished and every job is different. Feel free to contact us for an estimate based on your particulars.
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What are your thoughts on warranties (if any) for jack replacements? I have seen many with one year warranties, one with 10 year and one with 25. Those differences leave me confused. What are your thoughts on this? Thanks
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