Suspension Joints: Choosing the Right Chassis Part Replacement
Ball joints, tie rod ends and stabilizer links take a lot of abuse, so they need to be replaced once worn out.
It’s very important that we replace the original equipment properly. That includes installing the right replacement part, which isn’t always obvious because, when it comes to a vehicle’s chassis, there are two types of ball and socket joint technologies that we can choose from.
There’s the Metal on Metal design (often called ‘Grease-able’), and the Advanced Low Friction Polymer Bearing design (often called sealed). Each design has it’s own benefits, so the question of which design is best often comes up. The answer to that question is, it depends, so let’s look at both of them.
Metal on Metal or “Grease-able”
This is the original car technology and was common in older passenger vehicles. Metal on metal designs deliver high rotational torque and they use sintered metal bearings so they need a layer of grease between the ball and socket. That’s what the grease fitting is for. The ball joint, tie rod end or link can be serviced periodically with fresh grease. The grease not only lubricates the ball and socket, but most importantly it helps to flush out any contaminants, and it helps remove any metal particles that have been worn off due to friction.
This metal on metal design is proven technology for heavy loads and it’s still used for heavy duty and fleet applications today.
The thing is, without proper maintenance, metal-to-metal sockets can quickly degrade due to friction. Over time, friction between the metal ball stud and the sintered metal bearing can cause metal bearing to abrade and micro-flakes will chip off. The surfaces then become like sandpaper, wearing down the parts and creating extra space between the ball and socket. This is called endplay. Endplay changes a vehicle’s alignment, can negatively affect vehicle performance, and can cause the tires to wear out prematurely.
Advanced Low Friction or Non-grease-able (Sealed)
Sealed joints are often called “low friction” joints because they typically have highly polished ball studs and synthetic polymer bearings instead of metal bearings. These joints produce less internal friction, which makes steering easier, which is why this type of joint is used as original equipment on most – if not all – passenger cars and many light trucks today.
Lightweight and both corrosion and chemical resistant, the polymer bearings in low friction designs have a much smoother steering feel and easy steering returnability. As most advanced low friction designs are sealed, they’re maintenance free. Since new vehicles are designed to go longer in between service appointments, these sealed maintenance-free designs help reduce the incidence of failure on the road.
Advanced low friction ball joint technology has significant advantages for passenger cars and light trucks such as:
- The sealed designs also eliminate endplay due to friction, so they keep the alignment tolerances tighter, which means better steering.
- Low friction in the sockets reduces “memory steer” also known as “tight steering”. This is when a vehicle – after a lane change – continues to pull in the direction of the change. Low friction joints make steering safer and more precise.
- Low friction technology enhances the steering’s ability to return towards center after a full turn at low speed. Friction in the suspension system adds up, so it can become significant when considering all the components involved in making a turn.
- The polymer bearing gives a slight reduction in NVH (Noise Vibration and Harshness). Some polymer sockets provide a bit of compliance when stress is applied. The metal sockets have very little cushioning, and this can’t be adjusted or tuned increasing the experience of noise vibration and harshness in the vehicle.
- Most Advanced Low Friction designs do not have grease fittings. This is both environmentally friendly, and a reduced maintenance burden for the vehicle owner.
So here’s what we’ve talked about:
Metal to metal is ideal for older vehicles and vehicles that do a lot of heavy duty work. Regular maintenance is essential with these parts. Older vehicles have short maintenance intervals that give technicians the opportunity to “oil & lube” a vehicle more often, so aftermarket metal to metal chassis parts can be serviced as required.
Advanced Low friction is OE design on the majority of the vehicles on the road today. Advanced Low friction is the best way to restore the original steering feel and performance to a vehicle. Newer vehicles have longer maintenance intervals. No maintenance required on Advanced Low Friction
An important point is that this advanced OE technology could be a more expensive replacement. This should be explained to a client before hand, particularly one who is having a new vehicle serviced for the first time and remembers what they paid to service their old car. An important point to make is that this replacement will last longer and be less expensive over the life of the vehicle.
Selecting the correct aftermarket replacement technology is important to ensuring maximum safety, performance, feel and the restoration of the vehicles’ original driving dynamics.
What should you do?
- Ask yourself what type of vehicle you are repairing and how will it be used.
- Compare how often the vehicle is serviced with the manufacturer’s suggested repair schedule.
The answers should help select the ideal technology for that particular vehicle. In most cases, replacing components with the original OE technology and maintaining properly will ensure smooth, like-new performance from the vehicle.