Brakes - Explanation of Common Noises
Classification:BR87-005
Reference:
TS87-103
Date:
June 29, 1987
DISC BRAKE NOISE INFORMATION
APPLIED VEHICLE(S):
All Models with disc brakes (front or rear)
SERVICE INFORMATION
Some Nissan vehicles may exhibit brake noise under certain driving conditions. This Bulletin provides some information about normal and common noises and appropriate service procedures for each noise. Some of this information may be useful when explaining brake noises to the customer.
Refer to Technical Bulletin BR87-006, "Disc Brake Noise Countermeasure", for information about abnormal brake noises on Maxima, Stanza, and Stanza Wagon.
General Brake Information
Nissan brake systems have been carefully designed to provide optimum braking performance under various driving conditions. One of the most important components in the brake system is the brake pad material. The following factors have been taken into consideration to select the best pad material.
^ technical and government regulations
^ stopping distance
^ vehicle control while braking
^ high operating temperatures
^ pedal force
^ pad and rotor wear rates
^ moisture resistance
^ friction coefficient stability
^ operating noise level
Unfortunately, there is no one brake pad material that provides perfect performance in all of these areas. Changing the material to improve some factors often causes a performance reduction in other areas. Higher brake operating noise levels in some instances occur as a result of factors which ensure proper brake performance and safety.
Common Brake Noises
The following brake noises occur most frequently on Nissan vehicles. These noises do not indicate any malfunction or improper operation.
1. GROANING NOISE AT LOW MILEAGE (0-300 MILES)
^ noise occurs with light to medium pedal force
^ noise occurs during medium speed stops (20-40 mph)
^ noise usually does not occur on the first or second stop
^ noise occurs with warm or hot brakes (not cold)
^ there may be a low frequency "judder" vibration
Nissan applies protective coatings to the brake rotors and pads to reduce corrosion during shipping and storage. These coatings may cause this groaning noise until they are worn off. Under normal driving conditions, this usually takes about 300 miles. If this noise occurs during the first 300 miles, it is not necessary to attempt any repairs.
Service Procedure:
There is no service procedure to eliminate this noise permanently. Replacing the brake pads or machining the rotors may cause the noise to disappear temporarily, but it will return and continue until the coatings are worn off the rotor and pads.
2. GROANING NOISE (AFTER 300 MILES)
^ while the vehicle is barely moving, with light brake pedal force
^ more noticeable during warm, dry weather
^ most common on vehicles with automatic transmission
This noise is common on most cars with front disc brakes. There are no repair procedures to eliminate this noise.
3. SQUEAKING/SQUEALING NOISE
^ noise occurs with light to medium pedal force
^ noise occurs during low speed stops (5-20 mph)
^ more noticeable during warm, dry weather
This noise is common on vehicles with high-performance potential that must be able to stop in short distances from high speeds. Other brands of brake pads may eliminate this noise, but Nissan does not recommend them because they may have reduced pad life or inadequate performance in high speed stops.
4. HIGH-PITCHED SQUEAKING/SCRAPING NOISE
^ whenever brakes are applied
^ may come from just one wheel
Nissan uses pad wear indicators on many of its disc brake pads to provide an audible warning when the brake pads need replacement. Spring steel tabs that are riveted to the brake pad scrape lightly on the rotor surface when the pad is worn down to its lowest limit. The customer should hear the noise at this time and bring the vehicle to the dealer for brake pad replacement. The pad wear indicator will not damage the rotor surface if the pad is replaced in a reasonable time.
Replace worn pads with new parts. Check the rotor surface for damage and machine if necessary.