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Forums13
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Posts37,103
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Most Online117 Jan 16th, 2020
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#14056 - 05/03/15 06:33 AM
Re: Otis piston scarring ie grind marks
[Re: PO PISTON]
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Joined: Mar 2014
Posts: 212
Silly
enthusiast
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enthusiast
Joined: Mar 2014
Posts: 212
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Sanding sleeves are installed at the head of the jack, and as the elevator runs, it mildly sands the piston down. This is used to remove nicks, dings and scratches from a piston that has multiple points of issue. It wI'll reach 99% of the relevant parts of the piston. By simply using the overtravel and hand sanding the remaining 1% all of your piston that could go through the packing will be sanded.
That being said I find it odd that you had a leak, were re packed, and then blew the seal completely. Just reading here, it sounds like the repack may have been faulty as I would have expected it to simply leak again. The damage on the piston must be pretty substantial, as all re packs I have ever done, I checked the piston for marks to sand down as I did not want my brand new repack to meet the same fate as the old seal.
No your usage should not be held accountable for any damage to the piston. If the elevator was left in the down position for those first 4 years, and someone cleared the head of debri, it should have worked straight away. If the elevator was left up, there is the possibility of rust developing on the piston due to moisture in the air. 4 years of it would be substantial enough to damage your seals.
Hope this helps, and if you are in doubt, get a few bids from competing companies for the repair. You may be surprised by someone else's assessment. Good Luck.
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#14061 - 05/03/15 03:01 PM
Re: Otis piston scarring ie grind marks
[Re: DripCan]
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Joined: Aug 2012
Posts: 36
SEC Reject
newbie
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newbie
Joined: Aug 2012
Posts: 36
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I experienced a similar problem with an Otis replacement jack assembly. When the jack was installed, there were several vertical scratches running in lengths about 2-4 feet. Oil usage was excessive-to the point where it the drain line from the head of the jack wasn't able to keep up with demand when relieving it into a scavenger pump. We installed a piston sander and allowed it to run for several weeks, and then re packed the jack.
All was good for about 2 months-oil consumption was very reduced and the pit remained dry. Then a service call revealed oil all over the pit and first floor sill. The elevator had pumped all of it's oil into the pit. After the car was hoisted out of the pit, the culprit was a blown packing. It had fractured in a line around the circumference of the packing. It was determined, after consulting with Texacone, that it was a faulty packing, and unrelated to the earlier jack issues. Another packing was installed, and for well over a year the unit has been trouble free.
As long as your service provider takes appropriate action to correct any issues, this shouldn't become a long term issue. In our case, we were willing to stand behind the product and correct any issues, with the ultimate goal of making the customer happy through whatever means necessary.
Good luck.
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#14100 - 05/07/15 03:34 AM
Re: Otis piston scarring ie grind marks
[Re: DripCan]
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Joined: May 2015
Posts: 7
PO PISTON
stranger
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stranger
Joined: May 2015
Posts: 7
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#14101 - 05/07/15 03:51 AM
Re: Otis piston scarring ie grind marks
[Re: Silly]
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Joined: May 2015
Posts: 7
PO PISTON
stranger
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stranger
Joined: May 2015
Posts: 7
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Thank you so much for your detailed thoughts. I am really learning a lot and hadn't thought at all of the idea of a faulty packing job. Well, now that some time has passed, I had the same vendor who did the packing 6 months ago, return yesterday to fix the blown packing. After reading your post I didn't know if this was a good idea because he could have been the original problem, but the appointment was set and I felt like I didn't have the time or trust to go with someone else. Anyway, he gave me the texacone seal from the blown packing. It is very interesting. The green seal has over a half inch wide "groove" where it is worn away at a specific spot. He says this supports his theory that there is a problem with the piston. He originally thought the piston was ground down creating flat spots for oil to leak through the seal, and degrade the seal prematurely. Now seeing this groove it looks like there is a large nick or bump that is causing the wear. What do you think? I contacted Otis and they don't share that theory of course. They think that the piston was not aligned correctly causing it to wear the seal at that point. I cant' visualize what otis is saying because if the piston was not aligned I would think that the wear would be larger than a half inch, that the wear would be nearly one half side the the seal from the tilt or angle of the piston. Thank you for sharing your thoughts
Also if a piston has been ground done what does it look like? My piston looks like it has a pattern on it, like ripples/waves, my tech says that is what grinding looks like. When I compare that to my other piston in the elevator, the other piston doesn't have that wave/ripple pattern. Can grinding alone cause such oil leakage problems? If a piston was ground down, was Otis supposed to tell me at the time of install?
I will see if I can figure out how to post a picture of the seal....
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#14114 - 05/07/15 06:08 PM
Re: Otis piston scarring ie grind marks
[Re: PO PISTON]
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Joined: Mar 2014
Posts: 212
Silly
enthusiast
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enthusiast
Joined: Mar 2014
Posts: 212
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Standard is a loose term. Standard for me on a leaky repack is to first run the car with the bad seals still in place checking for damaged pistons and repairing them as needed. Sanding is a normal way to do this, and when done correctly has absolutely no problem with the new seal. Using a power tool to do this task can cause flat spots that may carry oil.
Alignment typically is a rather simple process, where was the piston for the first 10 years? Brilliant idea is to put it right back where you found it. I usually mark the platen hat, take measurements, etc. to ensure I have replaced the darn thing where it has lived very happily for a decade.
Again this issue may not have been with the provider, or the packing, or may have been one of them, or both. The spot on the seal looks very suspicious to me in that the slight arc visible looks like a very small radius in comparison to the over all seal radius. Seems to me that if the alignment of the piston was bad, that you would have had an elongated seal (oval) and not a roughly 1 1/2" spot. This could have been done by foreign debri, piss poor install of packing that caused damage, or a bad spot on the piston or joint if the piston is sectional (not sure they even have sectional twin posts, just a thought).
If I had to guess, I would say the piston has damage, horizontal, that is "eating" that section of the packing. The repair contractor should have addressed this issue at the time of the repack. It's like changing brake pads on a car, and not making sure the calipers are in working order, all you do is burn though another set of pads....
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