How Truck & Trailer Relay Valves Compare
The industry does not seem to encourage the standardization of air valves. There are a large number of differing relay valves. The list below may help you to better visualize the differences among relay valves. It is sorted by the number and size of the delivery ports. In this list of valves stocked by Plaza there are no exact equivalents although many valves are close to being comparable. Several of the valves on the list can be used as a relay valve in an ABS system but the specialized ABS relay valves are not included.
Unfortunately, you do not have good choices when replacing relay valves. Since any change in the diameter of a port can affect the braking response of the vehicle, the quickest and safest approach to replacing a relay valve is to use the same Bendix, Haldex, or Sealco part number that was used in the original equipment. Delivery ports for relay valves are generally oriented vertically or horizontally. The term “control port” represents the connection for the “service” line which signals the valve to do its job and most often only one control port is needed. A valve either includes holes for mounting or requires a separate mounting bracket. Several valves have some flexibility in how they are mounted. The Haldex RG2 valve can be reconfigured by rotating the cover which changes the orientation of the control port. A 4-port relay valve can be equal to two 2-port valves. For example, the Bendix R-12 valve pn 065125 with horizontal delivery ports can do the job of two Haldex RG2 valves pn KN28520. The crack pressures shown here are single values when in actual use a correctly functioning Haldex valve will have a crack pressure within plus/minus 1 psi (as claimed by Haldex). Thus a Haldex valve with a 5.6 psi crack pressure is roughly comparable to a Bendix valve that specifies a 5.5 crack pressure. |
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Relay Valves in Stock
| Crack |
| PN | Model | Delivery ports | Supply | Control | pressure |
Haldex | KN28520 | RG2 | 2 x 1/2" horz | 2 x 1/2" | 1 x 1/4" | 5.6 |
Haldex | KN28520X | RG2 | 2 x 1/2" horz | 2 x 1/2" | 1 x 1/4" | 5.6 |
Haldex | KN28131X | 2 x 1/2" horz | 2 x 1/2" | 1 x 1/4" | 4.6 |
Haldex | KN28061X | 2 x 1/2" horz | 2 x 1/2" | 1 x 3/8" | 4.6 |
Haldex | KN28065X | 2 x 1/2" horz | 2 x 1/2" | 2 x 1/4" | 4.6 |
Haldex | KN28071X | 2 x 1/2" horz | 2 x 1/2" | 1/4" & | 4.6 |
Bendix | 800481 | R-12DC | 2 x 1/2" vert, 2x3/8"h | 2 x 1/2" | 2 x 1/4" | 4.0 |
Haldex | KN28510 | RG2 | 2 x 3/8" horz | 1/2" & 3/8" | 1 x 1/4" | 5.6 |
Haldex | KN28510X | RG2 | 2 x 3/8" horz | 1/2" & 3/8" | 1 x 1/4" | 5.6 |
Haldex | KN28500X | RG2 | 2 x 3/8" horz | 2 x 3/8" | 1 x 1/4" | 5.6 |
Haldex | KN28060X | 2 x 3/8" horz | 2 x 1/2" | 1 x 3/8" | 4.6 |
Sealco | 110197X | 2 X 3/8" horz | 1 x 1/2" | 1 x 3/8" | 4.0 |
Sealco | 110365 | 2 x 3/8" vert | 1 x 1/2" | 1 x 3/8" | 4.0 |
Bendix | 065303 | R-12 | 2 x 3/8" vert & horz | 2 x 1/2" | 1 x 1/4" | 4.0 |
Sealco | 9125 | 3 x 3/8" horz | 1 x 1/2" | 1 x 1/4" | 5.5 |
Bendix | OR103009X | R-12 | 4 x 1/2" horz | 2 x 3/4" | 1 x 1/4" | 4.0 |
Bendix | 065125 | R-12 | 4 x 1/2" horz | 2 x 1/2" | 1 x 1/4" | 5.5 |
Haldex | KN28055 | 4 x 1/2" horz | 2 x 1/2" | 2 x 1/4" | 4.6/9.6 |
Bendix | OR103028X | R-14 | 4 x 1/2" vert | 1 x 1/2" | 1 x 1/4" | 4.0 |
Bendix | 800477 | R-12DC | 4 x 1/2" vert | 1 x 1/2" | 2 x 1/4" | 4.0 |
Bendix | OR102626X | R-12 | 4 x 1/2" vert | 1 x 1/2" | 1 x 1/4" | 4.0 |
Bendix | OR109264X | R-12P | 4 x 3/8" horz | 2 x 1/2" | 1 x 1/4" | 0.0 |
Haldex | KN28085X | 4 x 3/8" horz | 2 x 1/2" | 1 x 3/8" | 4.6 |
Bendix | 800365 | R-12 | 4 x 3/8" vert | 1 x 1/2" | 1 x 1/4" | 4.0 |
Sealco | 110415X | 4 x 3/8" vert | 1 x 3/4" | 1 x 3/8" | 4.0 |
Sealco | 110380X | 4 x 3/8" vert | 1 x 3/4" | 1 x 3/8" | 1.5 |
Sealco | 110380 | 4 x 3/8" vert | 1 x 3/4" | 1 x 3/8" | 1.5 |
Sealco | 110139X | 4 x 3/8" vert | 3/8" & 3/4" | 1 X 3/8" | 4.5 |
Haldex | A103600 | 4 x 3/8" vert | 1 x 3/4" | 1 x 1/4" | 3.0 |