Frequently Asked Questions
Q: What does a Height Control Valve do?
A: Height Control Valves maintain an air suspension at constant
height regardless of load. When the load on an air suspension system
is reduced, the air springs (or shocks) will lift the vehicle in
response to the lightened load. When the load is increased, the air
springs will be compressed and the vehicle will lower. A Height
Control Valve in the air spring circuit will allow air to enter or
leave the air springs as needed in order to maintain constant
height. We have a more
in-depth description here.
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Our Valve/Delco Valve
Q: Is this the same company that made the original Delco height
A: Yes. We have made the valves and links since 1981.
Q: How do I know if I have a genuine King of the Road (Delco)
A: Since 2003 “King of the Road” (our trade name) and “Dayton OH”
have been cast into the valve body next to the mounting bracket.
Older valves made before 1990 had the Delco name in this same
location. Unfortunately the period in between these dates had no
marking other than the part number located on the Control Arm.
Q: How can I tell if my valve is an original King valve?
A: All King Valves have a raised ‘KING OF THE ROAD’, cast
directly into the valve body. Legacy valves will have ‘DELCO
PRODUCTS’ cast directly into the body. Absence of the cast name
indicates an inferior counterfeit valve. These counterfeit valves
have not passed rigorous Delco/King of the Road testing and
Q: Why should I purchase your valves when I can get a foreign
made replacement for less money?
A: Our research shows that these copy-cat valves are not made
exactly like our valves. We have had customers tell us that they are
getting as little as nine months of service life using these parts
and it is driving up their service costs.
Q: What vehicles were Delco valves used on?
A: The original Delco valve was developed for air suspension on
1959 Cadillacs. The use of air spring suspensions extended to most
GM marques, being more common on luxury models. The valve also saw
heavy use on GMC transit buses, Ford and Mack trucks, and many makes
of semi-trailers. In the late 1970s the valves were used on air
shock suspensions for GM cars.
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Q: My valve has stopped working, now what?
A: Please check out our Troubleshooting page
Q: Do you have installation Instructions?
A: We have installation instructions
Q: Do you have Troubleshooting Info?
A: We have troubleshooting info
Q: Do you have maintenance info?
A: We have basic maintenance info
Q: I have an air leak in my system, should I replace the valve
with a new one?
A: It is unusual to find one of our valves that leak. 100% of our
valves are tested to a leak rate of 2sccm which is less than an
acceptable leak from one air spring. We always suggest checking the
fittings for proper tightness and air lines for crimps or cuts
before removing the valves.
Q: Do I need to install a check valve to prevent the air system
from bleeding down when the air compressor is not running?
A: Unlike our competitor's products most of our valves come with
a check valve on the air inlet. When the air pressure drops on the
air compressor side of the Leveling Valve this check valve will keep
the air in the springs or shocks from flowing back towards the
compressor, preventing deflation of the system.
Q: I would like to repair my Delco height control valve. Can I
purchase a rebuild kit from you?
A: We no longer sell the internal components necessary to
completely rebuild a valve. We do sell kits that include the various
air fittings, seals and check valves that are required for valve
Q: Do you have Teardown or Repair information?
A: We do not offer teardown or repair information on our site.
All KOTR valves are sold with a 30 month/100,000 mile warranty and
should be returned for warranty consideration within this time
period. If you have an older valve and would like further
information on possible repair or replacement, please contact us
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Identification and Purchasing Questions
Q: I need to purchase a new valve, where can I find the part
A: Our part number is located on the gold colored Control Arm
mounted on the side of the valve.
Q: How can I buy a replacement valve for my car or truck?
A: We currently sell through our distributor network. Please see
our distributor contact page here.
Q: I have a 1983 MCI 9 Bus - what is the part number for my
A: Unfortunately we do not have any way to look up which of our
parts were used on a particular vehicle. You will need to look up
the part number in the vehicle parts manual or check directly with
the manufacturer. We can usually cross reference the OEM part number
back to ours.
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Valve Application Questions
Q: Do you make special or modified valves?
A: We can engineer valve modifications and custom mounting
configurations. For more information, please see our Custom Valve
Q: Can you make a replacement valve for my vintage Cadillac?
A: We have many legacy Delco drawings in our database and have
produced replacement valves for several older vehicle makes,
including GMC, Cadillac, Chevrolet, Ford, AMC, and others. If you
can provide detailed pictures of the valve and application, we can
let you know if we have or can make your valve.
Q: Do you have replacement valves for my GMC Motorhome?
A: Yes, we do still manufacture the GMC Motorhome valve. This valve
is available through several of our distributors, listed
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