Torque-To-Yield Suspension Components (Ball Joints, Tie Rods And Control Arms)

Torque-To-Yield Suspension Components (Ball Joints, Tie Rods And Control Arms)

Always make sure to check the service information to get the right torque for a suspension component no matter what type of fastener. If you see an initial torque spec along with an angle in degrees, it is a torque-to-yield (TTY) fastener. TTY ball joint and tie-rod studs have two advantages. First, they can weigh less and still apply the same clamping loads. Second, the clamping loads are more consistent and controllable.

Some ball joints and almost all tie-rod ends use a tapered stud and hole with a nut on top to secure the stud to the knuckle. The 7-10º angled taper, along with a threaded stud and nut, lock the components together by tensioning the nut and stud.
 
Torque-to-yield (TTY) ball joint and tie-rod studs have two advantages. First, they can weigh less and still apply the same clamping loads. Second, the clamping loads are more consistent and controllable.
Identifying TTY Ball Joints and Tie Rods
The metallurgy and heat treatment of TTY bolts and regular bolts is different, and you can sometimes tell one from the other by their appearance. TTY ball joints and studs have an inset hex head at the end of the stud. This can be used when tightening to the specified torque and setting the torque angle.
 
Always make sure to check the service information to get the right torque for a suspension component no matter what type of fastener. If you see an initial torque spec along with an angle in degrees, it is a TTY fastener.
Installation
TTY ball joints and tie rods are usually installed dry. Do not apply any oil, grease, assembly lube or sealer on the stud or tapered bore. Lubricants increase the torque load on the bolt or stud, which may overload and stretch a TTY bolt too far, causing it to break. If a TTY fastener is over tightened, it can stretch beyond its limits and break.  The increased torque can also cause the female part of the taper to crack as to much clamping force is applied.
 
 

New torque angle tools designed to get into tough areas behind knuckles and control arms. This tool is from Brown Line Metal Works and attaches to any wrench.

Many ball joints may have an initial torque spec as low as 15-30 ft/lbs and torque angles are between 140º and 225º. Never guess or try to use your calibrated elbow; always look up the spec and use a torque wrench. make sure the washers on the studs are in good condition and installed in the right direction. If a washer splits or fails, it could cause a catastrophic failure.
Reusing TTY Items
Make sure you check the service information to see if a TTY ball joint or tie-rod end is reusable after it has been removed. Some manufacturers recommend a joint should be replaced, while others do not indicate if it should.

You May Also Like

Ride Height Sensors

If one of these sensors is replaced, it must be calibrated after it is installed.

Ride-height sensors not only measure the position of the suspension, but also the rate of movement. They are supplied with a voltage of around 5 volts. The signal voltage is changed as a magnet moves past a coil. Most sensors have three wires — ground, power and signal.

Internally, it is difficult to damage one of these sensors. Externally, the linkage that connects the sensor to the suspension arm can also be damaged. The connector can be damaged and cause a short or open and a code will be set. If one of these sensors is replaced, it must be calibrated after it is installed.

GM Rattle or Creak Noise From Front Suspension

The noise may be originating from the front lower control arm front bushing. Here’s how to correct it.

Mercedes Airmatic Suspensions

Diagnostic tips to aid your repair efforts.

The Complete Shock And Strut Swap

One mistake to avoid when replacing struts is reusing the bearing plates or upper mounts.

ADAS Sensor Corrections

When performing a calibration, you are adjusting the connection between the sensor, vehicle and surroundings.

Other Posts

Struts and Memory Steer

We can summarize the cause of memory steer in one word: binding.

Reprogramming ADAS Procedures

As a vehicle ages, the J2534 programming becomes even more important to the vehicle’s ADAS operation.

Air Ride Conversion Kits

Air ride and active shocks and struts will eventually fail – succumbing to either damage to or dry rot of the air spring.

MEYLE engineers solve Tesla’s squeaking problem

Hamburg engineers solve Tesla’s squeaking problem and develop technically enhanced control arm for Tesla 3 and Tesla Y