snap rings on pressed-in ball joints

extra safety when it counts

Over time, repeated ball joint replacements can deform the wishbone arm housing, reducing the press-fit strength needed for a secure connection. While OE parts rely on perfect tolerances and controlled factory assembly, workshop conditions can vary.

That's why MOOG includes a safety snap ring with all pressed-in ball joints. It acts as an added safeguard, helping prevent dislodgement if the press-fit isn't strong enough, and ensuring vehice control under tough driving conditions.

Engineered for real-world repairs, MOOG delivers peace of mind with every installation.

In the original equipment (OE) market, many pressed-in ball joints that come pre-fitted to wishbone arms do not include a safety snap ring for the following reasons:

MOOG_DYK23-19_Snap_Ring_BJ_PRMMO2309_IMG-A-

During the assembly of the wishbone arm, both components (particularly the arm body hole) have dimensions (1) that allow a perfect fit and the expected retention force of the ball joint.
OE and MOOG manufacturing facilities use servo presses that enable the control of the push-in force (3) of the ball joint and automatically reject assembled arms in which this pressing force value is too low.

However, after multiple replacements of ball joints, the wishbone arm body hole can become deformed or enlarged (2), preventing the achievement of a safe retention force for the ball joint. This is why car manufacturers rarely offer individually sold pressed-in ball joints.

Although MOOG strongly recommends replacing the entire control arm instead of individual components, MOOG also provides the ball joint as an alternative repair. Unfortunately, because most mechanical or hydraulic presses used in repair workshops cannot measure the pressing force, installers cannot be certain whether a safe retention force has been achieved during the assembly. (4)

To adress this issue, MOOG includes a safety snap ring with all its pressed-in ball joints, which can be inserted to secure the assembled product. (5)

The stopper integrated into the housing (6) supports the highest loads experienced by bal joints when a vehicle is subjected to extreme conditions (e.g., high speed, impacts with curbs, potholes, and poor road conditions). However, an additional 'extra stopper' is necessary to securely support lower loads in case the retention force resulting from the pressing operation is insufficient. This additional stopper helps prevent any risk of the ball joint dislodging from its body hole, which could have critical safety implications for vehicle control. The MOOG snap ring ensures secure assembly from a safety perspective, but may not prevent unpleasant knocking noises if the arm body hole is already deformed or enlarged. If such symptoms are noticed, the vehicle should be promptly taken to a workshop.

MOOG strongly advises against replacing pressed-in ball joints on a wishbone arm more than once. In such cases, or when there is uncertainty, it is recommended to install a fully assembled wishbone arm.

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