Have you experienced your steering wheel vibrate or shudder when braking? In this technical bulletin, we are going to look into what could cause this and how it can be alleviated.
Brake shudder is the vibration that you feel through the steering wheel when you apply the brakes. Brake shudder emerges as an aftereffect of issues related to the brake discs. Specifically, when the brake discs(rotors) have been influenced by Disk Thickness Variation (DTV). This alludes to the uneven wear of the brake discs and is the consequence of rotor run out.
If your brake rotors are unevenly worn, as soon as the brake pads interact with the flat spots within the rotor’s surface you will experience a vibration through the steering wheel that is commonly referred to as ‘brake shudder’. This sort of uneven wear to the rotors can be the consequence of a number of things. For example, the brake calipers not working correctly, the rotors not having been fitted properly or the bedding-in process of the pads has not been followed.
So you have brake shudder? How can you fix it? Firstly we need to identify the exact cause or source of the brake shudder, so we can isolate the problem. By and large, when a shudder or shaking is felt through the steering wheel whilst braking, generally it indicates the front rotors need to be examined. If on the other hand, the shuddering is felt through the brake pedal, then this generally highlights a problem with the rear brake rotors.
How do we cure brake shudder…In the event that a brake disc(rotor) develops DTV, the disc(rotor) will need to either be machined to resolve the uneven spots and make the disc flat or level. Depending on the condition of the disc(rotor) machining may not be an option, in which case completely replacing the damaged disc(rotor) is the only answer.
Brake calipers that aren’t operating the way they were designed, can likewise be a cause of brake shudder.
If a caliper is pushing the brake pad against the disc(rotor) without the brake pedal being applied then this can cause rotor run-out or the disc wearing unevenly.
If this is the issue, seized slide pins in the caliper are generally the offender.
To remedy the problem, just take out the caliper pins and regrease them with a High Performance Synthetic Lubricant. If the issue is not resolved with regreasing, then the calipers may need to be rebuilt or replaced.
Another common reason of brake shudder are problems, is an uneven mounting surface on the face of the hub.
Uneven rust and scale deposits can build up over time and affect the smooth surface of the hub face, which the creates an uneven surface for the disc to be mounted on. If this has occured on your disc(rotor), you will need to clean the area with some sandpaper and WD40 until the rust and scale deposits are gone.
This should be common practice when replacing or refitting brake discs to help prevent any instances of brake shudder in the future.
At the point when you are fitting a new set brake pads, it’s vital to bed them in appropriately. Subjecting your new brake pads to extreme thermal shock without following any sort of bedding-in procedure can promptly lead to uneven wear and brake shudder. Note: Some pads (such as titanium striped pads) require no bedding-in procedure. Check your pads manufacturer for guidelines.
Another small detail worth paying consideration on is your wheel nuts. Torqueing down your wheel nuts evenly, according to manufacturer specifications and utilising a quality torque wrench is another preventative measure against disc(rotor) run out.
When it comes to your brakes, don’t take any chances. It’s vital to keep them in first class condition. All things considered, they’re the only thing that is going to bring you to a STOP.