Back to Air Valves & Manifolds
Browse
AIR BRAKE & WHEEL View all
Browse AIR BRAKE & WHEEL
AIR BRAKE & WHEEL View all
Brass Push-Lock Reducing Union - 1/2" to 3/8" DOT Air Brake Tubing Coupling - Replaces Gates G31400-0806 8AB-6AB 177.13B6268
Brass Push-Lock Reducing Union - 1/2" to 3/8" DOT Air Brake Tubing Coupling - Replaces Gates G31400-0806 8AB-6AB 177.13B6268
Automann

Brass Push-Lock Reducing Union - 1/2" to 3/8" DOT Air Brake Tubing Coupling - Replaces Gates G31400-0806 8AB-6AB 177.13B6268

In stock
SKU: 177.13B6268
$12.64
  • Ships same dayOn in-stock orders
  • 30-day money-backShop with confidence
  • Secure checkoutEncrypted payment
We acceptAmazon American Express Apple Pay Diners Club Discover Google Pay Mastercard Shop Pay Visa

If you have a large order and would like to get a discount, please fill out this form.

Fitment

Fits these trucks

Universal - heavy-duty tractors and commercial trailersAir brake plumbing on tractors and trailersJoins a 1/2 in air line to a 3/8 in air lineDOT-approved heavy-duty air brake systems, FMVSS 571.106
Always confirm your year, make & model before ordering.
Part numbers

OEM & interchange numbers

5 cross-refs
Gates G31400-0806 Gates G314000806 Gates 8AB-6AB Gates 8AB6AB Velvac 017085
Direct 1-to-1 replacement for every number above. Tap any number to copy.
Overview

Step a 1/2 in air line down to 3/8 in in a single brass body with this DOT push-lock reducing union distributed by FleetPro Parts & Tires. It replaces the usual roadside bodge โ€” a coupling, a bushing and two more thread joints stacked end to end โ€” with one fitting and one sealing point on each tube. Every extra joint you delete is one less place for the system to weep down while the truck sits overnight. We stock these heavily right here in our Hanover Park, Illinois warehouse to ensure lightning-fast shipping for fleets, diesel repair shops, and owner-operators nationwide.

One Fitting Instead of Three: The Brass PLC Reducing Union Advantage

Manufactured by Automann to Fleet Standard specifications, this brass PLC union coupling is DOT-approved for heavy-duty air brake systems and meets FMVSS 571.106. Both ends are push-lock, so a 1/2 in tube goes in one side and a 3/8 in tube goes in the other with nothing more than a square cut and firm pressure โ€” no thread sealant, no torque spec, no flare tool.

That matters most on repairs and retrofits, where an original 1/2 in run has to feed a component plumbed for 3/8 in. Instead of adapting through pipe thread and hoping the sealant holds, you carry the reduction inside a single brass part rated for the brake circuit. It is a universal-application fitting that suits tractors, straight trucks and trailers alike.

At FleetPro Parts & Tires, we know the cleanest air repair is the one with the fewest joints. This Automann union is a direct replacement for highly searched industry numbers including Gates G31400-0806, Gates 8AB-6AB and Velvac 017085.

Vehicle Fitment & Compatibility

This DOT brass air fitting uses a universal design intended for the following commercial applications:

  • Make/Model: Universal - heavy-duty tractors and commercial trailers
  • System: Air brake plumbing, DOT-approved for heavy-duty air brake systems
  • Connection: 1/2 in push-lock tube end to 3/8 in push-lock tube end
  • Compliance: Meets FMVSS 571.106

Direct Replacement & Cross-Reference Numbers:

This Automann brass fitting serves as a direct replacement for the following part numbers:

  • Gates Interchange: G31400-0806, G314000806, 8AB-6AB, 8AB6AB
  • Velvac Interchange: 017085
  • Automann Distributor #: 177.13B6268

Technical Specifications

  • Component Type: Brass PLC Reducing Union Coupling
  • Size: 1/2 in to 3/8 in
  • Material: Brass
  • Application: Universal
  • Compliance: FMVSS 571.106, DOT-approved for heavy-duty air brake systems
  • Product Level: Fleet Standard Aftermarket
  • Brand: Automann (Distributed by FleetPro Parts & Tires)
Key features
  • Reduces in One Body: Takes a 1/2 in line down to 3/8 in inside a single brass fitting instead of a stacked coupling-and-bushing adapter.
  • Fewer Joints, Fewer Leaks: Each joint you delete is one less place for the air system to weep down while the truck sits overnight.
  • Push-Lock Both Ends: Square the cut and push โ€” no thread sealant, no torque spec and no flare tool on either side of the union.
  • DOT Approved for Air Brakes: Meets FMVSS 571.106 and is DOT-approved for heavy-duty air brake systems.
  • Gates and Velvac Interchange: Direct replacement for Gates G31400-0806, Gates 8AB-6AB and Velvac 017085.
Specifications
Component Type
Brass PLC Reducing Union Coupling
Size
1/2 in to 3/8 in
Material
Brass
Application
Universal
Compliance
FMVSS 571.106, DOT-approved for heavy-duty air brake systems
UPC
889626353857
Product Level
Fleet Standard Aftermarket
Questions
Will this fit my truck?
This part fits Universal - heavy-duty tractors and commercial trailers, Air brake plumbing on tractors and trailers, Joins a 1/2 in air line to a 3/8 in air line, DOT-approved heavy-duty air brake systems, FMVSS 571.106. Always confirm your year, make and model before ordering.
What part numbers does it replace?
Yes. It is a direct replacement that interchanges with Gates G31400-0806, Gates G314000806, Gates 8AB-6AB, Gates 8AB6AB, Velvac 017085.
How fast does it ship?
In-stock orders placed before 12 PM Central on business days ship the same day from our Hanover Park, IL warehouse, and typically arrive in 2 to 5 business days anywhere in the USA.
What's your return policy?
Unused items in original packaging can be returned within 30 days, backed by our 30-day money-back guarantee. If we ship the wrong part, we cover the return label and send the correct one.