Brakes - Vibration/Judder/Pulsation

Classification:
BR001-006

Date:
May 24, 2000

Reference:
NTB00-047

1998-00 ALTIMA BRAKE JUDDER

APPLIED VEHICLES:
All 1998-00 Altima (L30)

SERVICE INFORMATION

If a 1998-00 Altima exhibits steering wheel vibration or brake pedal pulsation when braking, it may be brake judder. Brake judder is created by excessive thickness variation of the brake rotors. In some cases the thickness variation is a result of excessive assembly rotor run-out. While brake judder is usually associated with the front brake rotors, the rear brake drums/rotors may cause it too.

NOTE:
Brake judder repair, as outlined in this bulletin, is covered by the 3 year, 36,000 mile warranty for these vehicles.

NOTE:
The most effective way to eliminate brake judder is to turn the disc brake rotors using the Ammco on-car brake lathe. This required tool tool will minimize the assembled brake rotor run-out more than the conventional off-car turning/installing on hub process and is required when making a repair for which Nissan pays.

Please note the following points when using the on-car brake lathe:

^ Prevent metal shavings from contacting or collecting on the ABS speed sensors. Remove any shavings that stick to the ABS speed sensor's magnet. It is best to clean the ABS sensor with the rotor removed.

^ Mark the exact location of the rotor (on the axle hub) before removing the rotor (see Figure 1).

^ Do not tighten the wheel lug nuts with an air impact driver. Tighten the wheel lug nuts to the proper torque specification. Uneven or high torque applied to the lugs may distort the brake rotor and hub, resulting in increased rotor run-out and excessive rotor thickness variation as the rotor wears.

^ If new rotors are required, install them on the hub in different positions (index) to achieve the lowest run-out reading (equal to or less than 0.0028", 0.07 mm) using a dial indicator. See Figure 2 . If run-out exceeds the assembly run-out specification, the new rotors must be turned using the Ammco on-car brake lathe (refer to NTB00-013).

SERVICE PROCEDURE





Altima (L30) Brake Judder Repair Flow Chart

Refer to the Repair Flow Chart shown to diagnose and repair the incident.

Rotor Indexing

When installing a new rotor, a rotor that has been surfaced off the car, or a rotor that has been removed for any reason, use the following indexing procedure to ensure the minimum amount of rotor run-out.

1. Remove the wheel assembly and ensure the rotor is fully contacting the hub. Clean the rotor to hub surface if it is rusty.

2. Install the rotor and all lug nuts. Tighten the lug nuts to 40 ft-lbs.





3. Place a reference mark on the rotor and hub (see Figure 1).





4. Measure rotor run-out with a dial indicator (see Figure 2). If the run-out is above 0.0028" (0.07 mm), continue with step 5.

5. Remove the lug nuts and shift the position of the rotor one lug then re-install the lug nuts and torque to 40 ft-lbs.

6. Measure rotor run-out with a dial indicator. Repeat steps 4 and 5 until the rotor is positioned with the least run-out.

7. If run-out exceeds the assembly run-out specification (0.0028", 0.07 mm), the new rotors must be turned. For front rotors, use of the Ammco on-car brake lathe (refer to NTB00-013) is required for repairs for which Nissan pays. For rear rotors, use an off-car brake lathe.

NOTE:
When re-installing the wheels, evenly torque the wheel lug nuts to the proper torque specification (i.e., 98 - 117 Nm, 10 - 12 Kg-m, 72 - 86 ft-lb). Do not tighten the wheel lug nuts with an air impact driver.

CLAIMS INFORMATION

Please reference the current Nissan "Warranty Flat Rate Manual", Sections "PB", "PC" and/or "PD" and choose the Op Code, or combination of Op Codes, that best describes the repair(s) performed.