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Replacement Pin Box Tank Valve for Lippert or UltraFab TrailAir Pin Boxes

Replacement Pin Box Tank Valve for Lippert or UltraFab TrailAir Pin Boxes

Item # LC156740
Our Price: $45.23
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Shipping Weight: 0.07 lbs
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Replaces a damaged pin box tank valve on your TrailAir pin box. 1-800-940-8924 to order Lippert accessories and parts part number LC156740 or order online at Free expert support on all Lippert products. Great prices and Fastest Shipping for Replacement Pin Box Tank Valve for Lippert or UltraFab TrailAir Pin Boxes. Accessories and Parts reviews from real customers.
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  • Reviews (16)
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  • Videos (1)
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Lippert Accessories and Parts - LC156740

  • Fifth Wheel King Pin
  • Valves
  • Lippert Pin Box
  • UltraFab Pin Box
  • Lippert

Replaces a damaged pin box tank valve on your TrailAir pin box.


  • Replaces a damaged pin box tank valve on your TrailAir pin box
  • Fits TrailAir boxes
    • Lippert TrailAir Flex Air - (LC328492, LC328484, and LC369535)
    • Lippert TrailAir Air Ride - (LC155933, LC158778, LC155943, LC179879, LC155930, and LC171200)
    • Ultra-Fab TrailAir Air Ride - (UF35-946212, UF35-946223, UF35-946209, UF35-946219, UF35-946208, UF35-946216, UF35-946215, UF35-946213, UF35-946206, UF35-946211, UF35-946214, UF35-946220, UF35-946210, UF35-946216, UF35-946222, and UF35-946224)
  • Includes 1 replacement valve

156740 Replacement Pin Box Tank Valve for Lippert Components (LCI) or UltraFab TrailAir Pin Boxes

Video of Replacement Pin Box Tank Valve for Lippert or UltraFab TrailAir Pin Boxes

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Lippert or UltraFab TrailAir Pin Box Tank Valve Review

Hey everybody, how's it going Today, we're gonna be going over and showing you how to install Replacement Air Tank Valve, for Curt Flex Air and Trail Air 5th Wheel Pin Boxes. So here is what our replacement tank valve looks like installed. This is actually gonna be an exact replacement for the Factory Tank valves. So this isn't any sort of aftermarket part another manufacturer makes, this is the one the manufacturer made and equipped from this pin box originally. So it is an exact fit replacement. So there's a couple different reasons that you may want to replace the valve here on your pin box.

Number one, someone who's just overhauling their pin box, they do make quite a bit of replacement parts for these, such as the airbag and the strep. So while you're doing that, you might as well just replace the tank valve as well. But one of the more common reasons that people replace this, is it can actually leak over time from one reason or another. It could be the threads and how they thread into the airbag or it could be the actual inflation valve at the top. It is a potential for leaks.

So a good way to check that is, just take a soapy water solution once you've inflated your system, and just spray everything down and that'll easily allow you identify the cause of your air leak, whether it's the actual air spring or the inflation valve. So in regards to compatibility, this specific valve here is gonna work on a couple different pin boxes. Whether you have the Curt Flex Air, the Lippert Trail Air Flex Air, or the Ultra-Fab Trail Air Pin Box; this is going to be the correct replacement air tank valve. So now that we've gone over the replacement part here, let's go ahead and show you how to install it. So before we start our installation, we need to make sure that we've removed all the pressure from the airbag.

So we're gonna remove that yellow cap there and then we're gonna take some sort of object there, so we can depress the plunger inside that valve. Just make sure all the air is out. We've already done that. So there shouldn't speed too much shooting out here, but we're basically just gonna be listening for it. And I can't hear any more air coming out.

So now we're ready to remove the valve. We're gonna take a Deep Well 9/16-inch socket, you can see we have a little cut out here, so we're gonna place that over the valve. Now this is on there pretty tight, but we're just gonna break it loose here. Once we get it broken loose, it should be a lot easier to remove. There is some thread tape on these threads here. Just go ahead and remove it, just like so. So now if we look down inside this little cut out here, we wanna make sure that we get all that thread tape off there. We don't necessarily want to use any material to clean that out, cause you don't want anything falling back into the bag. Just kind of take your finger here, and get as much as that extra thread tape out as you can. Next, we're gonna take our valve here, I'm just gonna begin threading it into the bag by hand. So you are gonna get some resistance after a couple turns, because that white stuff on the threads there, is a thread sealer or a thread tape, which we need in order to make sure air doesn't escape through the threads. So once you get a couple turns there, you should be able to turn it anymore by hand. We'll have to switch over to our wrench here, And now we'll begin tightening it. So there isn't an exact porch value for this, it's gonna be more or less by feel and also sight. We're gonna give it a couple turns, we're gonna remove our wrench and just sort of judge how much of the threads are into the bag here. So I'm gonna go a little bit more. I kind of eye the factory one to see how much they have tightened it down. And they actually went on there quite a few turns, so we're gonna try to mirror that as best as we can, but looking down there now, I would say we have a good amount of threads into the bag there. There's only a couple more on top. All the thread locker is on the threads there, so it should seal up pretty nicely. And I think we're gonna call that good, as far as tightening down. Now, we want to ensure that there's no leak, so what we're gonna do is, we're gonna remove the cap and we're going to inflate our system here. Now I don't have an exact PSI for you guys. I would just hold it on there for a couple of seconds, so don't go too overboard here but we do need enough air in there to introduce any leaks, if there are present. We'll go ahead and hold that on there for a few seconds. Call that good. And now I'm gonna come back with a soapy water solution and we're gonna spray down this fitting here. And basically what we're looking for is wrapping forming bubbles around the threads here, that our valve screws into the airbag. So go ahead and spray that down there and look it over to make sure there's no leaks present. So that pocket in there does kind of hold water but I'm not seeing any bubbles escaping from there, so that's gonna ensure that we don't have any leaks there. Now wrapping forming bubbles, they're gonna get slow bubbles cause it is soap after all, but basically we're looking for those rapid forming ones. And again, that's gonna indicate a leak. If we did have a leak, we wanna tighten this up a couple more turns or back it off, and reapply some thread sealers such as some thread tape. Go ahead and tighten it down again, but as you can see here, we don't have any bubbles whatsoever. Therefore, I've ensured that the tank valve is installed correctly. Next we're gonna take a paper towel here, just try to get as much of that water down in there out, as we can. Not looking for perfection here, just getting as much as we can out. And then once that's done, we'll just simply reinstall a cap here. But there we go. That's gonna do it today, for our looking installation of the Replacement Tank Valve, for the Curt Flex Air or Trail Air 5th Wheel Pin Boxes..

Customer Satisfaction Score:

Customer Reviews

Replacement Pin Box Tank Valve for Lippert or UltraFab TrailAir Pin Boxes - LC156740

Average Customer Rating:  4.8 out of 5 stars   (16 Customer Reviews)

Replaces a damaged pin box tank valve on your TrailAir pin box.


Works as it should.

Etrailer needs
to do a better job of qualifying who they use to ship during the checkout process. USPS won't come to my house and told me the order would be returned to sender, So I ordered a second valve due to timing needs, then both showed up in my PO Box on the same day... Spent $100 to get a $50 part.


I chose Etrailer parts because they had a good selection of high quality replacement parts for my AirRide 5th wheel hitch (and everything else I need for my truck and trailers). My original equipment was very old, and I expected it to be impossible to find a replacement that fit, but George at Etrailer had them NEW. I installed the parts a year ago and I have been very happy. The quality is clear after a year of hard use--the parts still look and perform like new (better than the rest of the trailer!). The pictures show it ... the shock absorber and air bladder and steel yellow valve stem still in top shape with almost a thousand miles on them. So glad I have Etrailer a try!


Used a 45 degree elbow so I didn't have issues filling it with air due to the bubble level.


Replacement air bag works excellent. Many thanks to Tommy C for his efforts dealing with the mfg. and obtaining the right air bag for my application.
Thanks again,
John Brewer


As advertised.


They went beyond the call. I needed the new valve before the 30th of June. I got it on the 27th of June.


Hard to find item, only etrailer had it. Thank you. Will definitely use etrailer again.


Very professional and knowledgeable personnel and they try hard to get your order shipped as soon as they can. Will definitely order from them more in the future.


Delivery was timely and parts appear to be good. Will install on my next days off.









See what our Experts say about this Lippert Accessories and Parts

  • Replacement Air Valve for Trailair Pin Box 155933
    The current version of the Trailair pin box 155933 does use the replacement valve part # LC156740 that you referenced so this would be the correct replacement.
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    The Replacement Valve # LC156740 is 1/2 inch NPT. I went out to our warehouse to confirm for you.
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  • When to Set Air Pressure in Trailair Flex Air Cushioned Pin Box
    To get the best ride quality you want to inflate the air bag of your Trailair Flex Air part # LC328484 when the trailer is fully loaded as that will ensure that the shock and air bag will be as effective as possible. If you'd have to exceed the 120 psi limit of the bag you most likely are exceeding the weight capacity of the pin box. Inflate the air bag with only enough air to raise the pin box to the ride height mark on the front of the shock absorber with the truck and trailer at rest.
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  • Replacement Inflation Valve for Trailair Air Ride 5th Wheel Pin Box # LC158778
    The replacement inflation valve for your Trailair Air Ride 5th Wheel Pin Box # LC158778 is called their Pin Box Tank Valve. This item's part number is # LC156740.
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  • Air Spring for Air Ride Pin Box is Leaking and Air Bag Warranty
    I reached out to the manufacturer, Lippert, who told me the Replacement Air Spring for Trailair 5th Wheel Pin Boxes # LC432404 has a 1-year warranty from the date it was purchased. It should definitely not be losing 20 psi in one day so it sounds like you just have a leak, which may be from the air bag or the inflation valve. You will want to use a solution of soap and water and spray the bag and valve, and wherever the bubbles are forming, you'll know that's where the leak is. The air...
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  • Air Pressure Adjustment of Rubber Air Spring in TrailAir 5th Wheel Pin Box
    The rubber air spring inside a cushioned pin box like the TrailAir could require addition of air pressure each time you hitch if a long period of time has elapsed between trips or if the trailer has been loaded with more weight (or weight placed in a different location within it) than it usually has. If you tow the 5th wheel and park it for two days, without altering the cargo weight, then you should not need to refill the air spring. If the spring clearly loses air pressure at a recognizable...
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  • How To Fix Trailair Flex Air 5th Wheel Pin Box Losing Pressure
    There could be one of two places that you are loosing air from on your Trailair Flex Air 5th Wheel Pin Box. In order to determine where you will want to mix up a solution of soapy water and spray the airbag and inflation valve down while under pressure. If you see any bubbles forming then you know that is where the leak is occurring. If the leak is on the actual airbag then it will need to be replaced for which we have the Replacement Air Spring for Trailair 5th Wheel Pin Boxes part # LC432404....
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  • Is Uneven Shape of Trailair Pin Box Air Bag a Problem
    Thank you for the photo of your TrailAir pin box's rubber air spring. The shape/position of the bag are not necessarily an issue. Just in case I do suggest that you check that your air bag is inflated to the correct pressure. There is a simple way to determine the correct pressure. Hitch your trailer and them slowly add pressure through the air bag's Schrader valve. Add pressure until the two black arrowheads on the yellow sticker on the shock are just visible. Please refer to the linked...
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    Image 1 for Image 2 for
  • Replacement Air Spring and Valve for Trailair 21K 5th Wheel Pin Box
    It sounds like you're looking for the Replacement Air Spring for Trailair 5th Wheel Pin Boxes part # LC432404 and Replacement Pin Box Tank Valve for Lippert or UltraFab TrailAir Pin Boxes part # LC156740. I have attached for you below videos I made replacing each of these parts.
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  • Where Could Trailair Flex Air Pin Box Be Leaking
    The only two things that could leak on the Trailair Flex Air Pin Box is the Replacement Air Bag part # LC432404 or the Replacement Valve part # LC156740. In order to check for leaks we recommend that you inflate the air bag to around the max psi which is 120 and then spay it down with a soapy water solution. If rapid forming bubbles occur then that indicates a leak. The assembly can also be dunked in a tank of water as you described. We recommend 4-6" between the loft of the trailer and...
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  • Should Trailair Flex Air Pin Box Lose Air When Sitting For A Month
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  • How to Find Air Bag Leak on a Trailair Replacement Pin Box on a 5th Wheel Trailer
    The 90 psi is within the capacity of the air bags used in Trailair pin boxes so it isn't that the pressure is too high. It does sound like there is a leak. The leak is likely at the inflation valve. You can put soapy water around and on the valve and see if it starts to bubble. That would indicate a leak. Or, even better, you could use Detect-A-Leak, # V02126, which is a lot easier than soapy water. If it is leaking at the valve you can replace the valve. The replacement valve is # LC156740.
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    The Trailair Flex Air 5th Wheel Pin Box - Lippert 1621 - 21,000 lbs # LC369535 will have an air bag pressure range between 20 and 120 psi. Lippert techs say that sticker is there to assist but is not always accurate due to the fact it is a sticker that can be slightly misplaced. If your air bag is within the 70-100 psi range then they said not to worry about the sticker. It is a reference point and not a perfect guide. I recommend using a pressure gauge to confirm the 70-100 psi as...
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    I spoke to my contact at Lippert about the issue you are having with the Trailair Flex Air 5th Wheel Pin Box like part # LC369535 on your 2011 Ford F-350. They stated that the arrow on the shock is just a reference point and not something that you should really use as your absolute guide as they have had issues with the sticker being misplaced. The reason that the ride is so rough is that you are at near max psi of the airbag which is 120 psi. They recommend that you adjust the pressure...
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    I have two air ride pin boxes that will work in place of the MorRyde RPB72-1621-HD on your 2015 Heartland Landmark 365 Ashland and they will provide you with a 21,000 lb weight capacity. For this, we have the 5th Airborne Premium Fifth Wheel Air Ride Coupler part # 5AB-E1621-610 or the Trailair Air Ride 5th Wheel Pin Box part # LC158778. I personally have not had a chance to use either of these pin boxes but I can say our customers generally prefer the Trailair Air Ride 5th Wheel Pin Box...
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Info for this part was:

Employee Jameson C
Expert Research:
Jameson C
Employee Jeffrey L
Expert Research:
Jeffrey L
Employee Dustin K
Video Edited:
Dustin K
Employee Shelly K
Updated by:
Shelly K
Employee Mike S
Updated by:
Mike S
Employee Wilson B
Written by:
Wilson B
Employee Jonathan Y
Video by:
Jonathan Y
Employee Conner L
Installed by:
Conner L

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