Truck with no air dump valve switch, can one be installed?

Discussion in 'Experienced Truckers' Advice' started by combo7, Jan 22, 2023.

  1. combo7

    combo7 Bobtail Member

    Jan 19, 2016
    Worcester MA
    Hello Drivers, I have a 2004 Freightliner Columbia S60 12.7 that doesn't have an air dump valve on the dashboard for when dealing with low trailers , is there a way to install one , is there a kit that I can buy ?
    Thank you in advance drivers.
    OLDSKOOLERnWV Thanks this.
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  3. blairandgretchen

    blairandgretchen Road Train Member

    Dec 9, 2011
    South west Missouri
    I’ve been working a project the last few weeks, that requires lowering truck and trailer.

    You can easily disconnect the leveling valve on the tractor and raise or lower.

    I installed an air dump switch on the trailer, manual, at the rear. I had to replace the 2 port leveling valve with a 3 port.

    I assume you’d have to do the same on the truck and run air lines into the cab to the switch.

    I think there’s an air/electric option too.
  4. Hammer166

    Hammer166 Crusty Information Officer

    Aug 18, 2007
    ~8600+' and loving it!
    Yep! Several ways to go about it, just need a valve that block the input (from the height control valve) and dumps the bags when air is applied. It could be as simple as a 3-way valve outside the cab, or using a relay valve like the factory setups controlled from the dash.
  5. blairandgretchen

    blairandgretchen Road Train Member

    Dec 9, 2011
    South west Missouri
    My tiny brain had issues with the way it worked - I needed to have air supplied to the brakes to roll the trailer whilst the bags were dumped.

    I finally figured out that the 3 port allowed both these functions, and relied on fully charged air system.

    OLDSKOOLERnWV Captain Redbeard

    Nov 29, 2011
    West Virginia

    If I don’t forget I’ll take a picture of my factory setup and share as well. Very easy to add on external or in the cab….
  7. loudtom

    loudtom Road Train Member

    Aug 26, 2016
    They make leveling valves with the dump pilot integrated, or you can purchase a dump valve that goes on after the leveling valve. The dump pilot port has a valve that is normally held open when there is no air supplied to it. This allows the system to function normally. When you supply air to the pilot, it closes off the air from the leveling valve and it opens the exhaust port, which allows the air bags to empty into the atmosphere.

    You have to decide which method you will use to supply air to that pilot port, and how you will control it. You can run a line from the tank(tee off of any line that always has tank pressure) to the pilot and put a simple ball valve that you open and close by hand. If you don't want to get in and out of your cab every time you do it, you can install the valve on your dash, but then you will need to run air lines to and from that valve. You can also run a normally closed electric solenoid valve, then run the wires to a switch on the dash. When you flip the switch and energize the solenoid, it opens the valve and air flows to the pilot, which dumps the air bags. It is a good idea to put a light or buzzer on that switch so it reminds you to inflate your suspension before you drive off.
  8. HoneyBadger67

    HoneyBadger67 Road Train Member

    Dec 15, 2018
    Savannah, TN

    I had a dump valve installed on a century. I *believe* its electric, but confess I didn't pay a lot of attention.
  9. Ridgeline

    Ridgeline Road Train Member

    Dec 18, 2011
    There is NO kit but it is easily setup.

    You need a Hendrickson VS-228 with integral dump valve

    You will also need a dump valve or any air valve.

    AND you will need the DOT 1/4" tubing to go from the valve for the air bags (VS-228) and the dump valve - maybe 25 feet should do it.

    The way the VS-228 works is you just need to open the dump port and it releases the air out of the bags.

    There is instructions on the Hendrickson's site - pretty clear on how to install it
  10. Dino soar

    Dino soar Road Train Member

    Dec 8, 2017
    This is the right answer.
    D.Tibbitt Thanks this.
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