HPI Baja Front Upper Arm Ball Ends Nylon Socket with Steel Balls BJ054/BE by GPM  [BJ054/BE]

Front upper arm ball end replacement

The BJ054/BE ball ends are aftermarket replacements designed to fit the front upper arm assembly on HPI Baja models. They combine a nylon housing with hardened steel balls to provide a low-friction pivot between the alloy upper arm and the steering or linkage hardware.

As a scale accessory these ball ends focus on durability and consistent movement rather than changing suspension geometry. Fit them when factory ball ends show wear, excessive play, or after routine servicing to restore crisp steering response and predictable suspension action.

Installation is straightforward: remove the worn ball end from the arm or linkage, press the new nylon housing onto the mating post, and confirm free rotation of the steel ball inside the socket. After installation, check for binding or axial play and recheck during the first run to ensure correct seating.

Tuning tip: nylon housings usually give smoother articulation than brittle plastics while steel balls resist surface wear. If you notice lateral play at the joint, replace the ball end rather than over-tightening linkages, since extra preload can cause binding and alter suspension behavior.