Air Lift 21837
90° swivel elbow · 1/8-in male NPT × 1/4-in PTC
Nickel-plated elbow with factory-applied sealant on the male NPT thread, used in many LoadLifter 5000 and RideControl kits.
Air Lift 1/4-Inch Airline Fittings: Elbows, Tee & Union
Air suspension plumbing uses several connectors that can look similar but have different jobs. A straight union repairs a run of air line, a tee joins three ¼-inch lines, and a threaded elbow connects tubing to a compatible air spring or control component. This guide compares four exact Air Lift fittings stocked by NewRVParts, helping you choose by the connection on each end instead of by appearance.
Which connection does your system need?
Male NPT to push-to-connectFor an air spring or accessory with the appropriate female ⅛-inch NPT port, use the specified elbow with a ¼-inch tubing connection. The threaded and tube ends serve different purposes.
Three-way teeThe 21838 has three ¼-inch push-to-connect openings. Air Lift identifies it for tying two compatible air-spring lines together into a single-path, shared-inflation arrangement.
Two-way straight unionThe 21840 has two ¼-inch tubing openings. It connects two compatible airline ends in a straight run rather than splitting air into a third branch.
PTC does not mean AN flare. In these model descriptions, ¼-inch PTC means a push-to-connect fitting for compatible air tubing. It is not an interchangeable ¼-inch AN flare fitting. Match the hose outside diameter, fitting part number, thread type and manufacturer's installation instructions before connecting the system.
Air Lift 21837, 21838, 21840 and 21848 comparison
The manufacturer identifies both 21837 and 21848 as ⅛-inch male NPT to ¼-inch PTC swivel elbows. Keep their distinct MPNs when replacing a fitting rather than assuming that an identical nominal port specification establishes identical construction or fit for every kit.
| MPN | Fitting | Port sizes | Typical purpose | Product |
|---|---|---|---|---|
| 21837 | 90° swivel elbow | 1/8-in male NPT × 1/4-in PTC | Threaded-to-tube connection | View |
| 21838 | 3-port union tee | Three 1/4-in PTC connections | Single-path air spring plumbing | View |
| 21840 | Straight union | Two 1/4-in PTC connections | Connect two airline segments | View |
| 21848 | 90° swivel elbow | 1/8-in male NPT × 1/4-in PTC | Alternate elbow MPN | View |
Compare the four Air Lift fittings
Each item links to its exact NewRVParts listing. The original kit's parts list is the best starting point when replacing a lost or damaged fitting.
Air Lift 21838
3-port union tee · Three 1/4-in PTC connections
Joins two air spring lines with a common inflation line where the system is designed for shared pressure.
Air Lift 21840
Straight union · Two 1/4-in PTC connections
In-line union for joining compatible 1/4-inch outside-diameter push-to-connect tubing without adding a third branch.
Air Lift 21848
90° swivel elbow · 1/8-in male NPT × 1/4-in PTC
Air Lift identifies the same nominal male-thread and tube interface as 21837; verify the original fitting number for any construction or application differences.
Airline plumbing questions
Can I use 21838 instead of 21840?
Not as a like-for-like replacement. 21838 is a three-branch tee, while 21840 joins two tubing ends in a straight run. Select the connector for the intended air circuit.
Are 21837 and 21848 identical?
Air Lift lists the same nominal ⅛-inch NPT male to ¼-inch PTC swivel-elbow connection on both, but assigns separate MPNs. Confirm the original system's replacement part rather than assuming all construction details are the same.
Can a tee connect two air springs to one fill valve?
Air Lift specifically describes 21838 for some single-path systems that share inflation pressure. Check whether your installation should use one shared line or separate pressure control for each side.
Why does a new push-to-connect air fitting leak?
A line cut at an angle, an incompletely inserted tube, a damaged line or a loose connection can cause leakage. Depressurize first, then inspect the fitting and tubing. Air Lift recommends checking with soapy water after reassembly.
Does a fitting increase my truck's load rating?
No. These are air-system service parts. Suspension accessories do not change manufacturer GVWR, axle, hitch or tire limits.
Related Air Lift equipment guides
- Air Lift Compressors: Single-Path vs Dual-Path Systems
- Air Lift 1000 vs 1000HD: Ram 1500 Spring & Compressor Kits
Always relieve air pressure before servicing plumbing. Inspect air lines for abrasion, heat exposure and routing damage, and follow the original air-suspension kit instructions.
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