How it connects
Slip-fit / sliding hex engagement where the male hexagonal end of the torsion bar slides into the broached female hexagonal socket to transmit high torsional loading without slipping.
Male and female halves
Female socket; mates by sliding over a matching male hexagonal forged bar end.
Usually connects to
- Matching vehicle torsion-bar male hex end
Common sizes
- Hex sockets typically 25–45 mm (about 1–1.75 in) AF, often 30–45 mm on trucks/SUVs.
- GM 2500/3500 HD examples are about 45 mm (1.77 in); size depends on chassis.
Where it is used
Truck/SUV front torsion-bar suspensionPickup/heavy-vehicle levelingOff-road leveling kitsMilitary suspension
Variations
- OEM factory torsion key
- Clocked/re-indexed aftermarket lift/leveling key
- Lower-control-arm hex receiver
- Broached through-hex or blind socket
- Splined torsion-bar receiver (different profile)
How to recognise it
Recognizable as a large 6-sided internal (female) hexagonal opening broached through a heavy forged steel or cast iron suspension lever (torsion key) or control arm pivot.
Often confused with
| Confused with | How to tell them apart |
|---|---|
| Splined torsion bar engagement | Splined torsion bars feature numerous involute or straight splines around the circumference rather than a simple 6-sided hexagonal profile. Splined sockets feature multiple fine radial teeth/involute splines rather than a 6-sided internal hexagon. |
| Hex drive bit socket | Tooling sockets are hand or impact wrench accessories rather than heavy-duty forged structural suspension linkage components. |
| splined torsion bar receiver | Hex receiver has a 6-sided internal geometric profile, whereas splined receivers feature numerous fine radial teeth (splines). |
| standard hex drive / allen socket | Torsion bar hex receivers are heavy forged structural suspension components designed for continuous spring torsion, not hand tool drive fasteners. |
| Standard hex drive / socket wrench socket | Standard hex sockets drive fastener heads and have square drive inputs, whereas torsion bar sockets are heavy-duty structural vehicle suspension levers designed for high continuous torque. |
Also called
torsion key hex sockethexagonal torsion bar sockettorsion bar keywaytorsion bar hex female receivertorsion bar hex openinghexagonal torsion bar receiver
Good to know
Commonly encountered on GM, Chrysler/Mopar, and Dodge light truck independent front suspension systems using torsion springs.
Related connections
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