Brakes - Shudder on Light Application
83amcjeep211E062
OCTOBER 1983
1980-83 EAGLE 30-50 SERIES
BRAKES Attention: Workshop, Parts Department.
BRAKE SHUDDER
Information
Some 1980-83 Eagles may develop a shudder-like brake vibration that occurs during light brake pedal applications but does not occur when additional pressure is applied to the brake pedal.
Service correction involves verifying and eliminating the brake shudder as outlined in the following procedures.
ROAD TEST AND VERIFICATION
NOTE: The following road test verifies a brake vibration or shudder Refer to the appropriate AMC Technical Service Manual for diagnosis of any other vibrations noted during the road test
1. Drive the vehicle at 50-55 mph, apply light pressure to the service brakes and note vehicle reaction. Repeat this operation at least two more times.
a) If no vibration occurs, return the vehicle to the owner.
b) If vibration or shudder is evident during brake application, proceed to step 2.
2. Determine if the problem is related to the front or rear wheels as follows:
^ Block or tie the parking brake release mechanism in the fully released position. Then drive the vehicle at 50-55 mph, lightly apply pressure to the parking brake and note vehicle reaction.
CAUTION: Excessive parking brake application can cause rear wheel lockup.
a) If vibration or shudder is evident, proceed to Rear Brake Service Procedure.
b) If no vibration or shudder is evident but vibration was noted during brake application in step 1, proceed to Front Brake Service Procedure.
FIGURE 1 - ROTOR MOUNTING FLANGE:
FRONT BRAKE SERVICE PROCEDURE
Inspect both front wheel hubs at the rotor mounting flange surface (inboard of the five mounting holes) for a machined step about halfway around the flange (Fig. 1). If the step is present, replace the original hub and bearing assemblies with replacement assembly, 3238527. Refer to the hub and bearing removal and installation procedures on pages 2F-22 and 2F-23 in the 1982 AMC Technical Service Manual.
REAR BRAKE SERVICE PROCEDURE
1. Remove the rear wheels, brake drums and axle hubs. Inspect the brakeshoes, springs, wheel cylinders and backing plates. Replace worn components and proceed to step 2.
NOTE: If the vehicle is beyond the warranty period, replaced parts are not warranty eligible.
2. Install replacement rear axle hub and brake drum assembly, part number 3231640 on each side of the rear axle. Refer to the axle hub replacement procedures on pages 2F-14 and 2F-15 in the 1982 AMC Technical Service Manual.
3. Install the rear wheels and tighten the wheel nuts alternately and evenly to 75 foot-pounds (102 N-m) torque.
CAUTION: To avoid distorting the hub and brake drums or damaging the wheel studs, do not overtighten the wheel nuts. Tighten them to specified torque only.
BRAKESHOE BURNISHING
If the brakeshoe were replaced in step 1 of the service procedure, they must be burnished, as outlined in the following procedure.
1. Make 10 to 15 hard stops in reverse, alternating with a forward stop between each reverse stop to adjust the brakes and provide maximum shoe-to-drum contact during burnish stops.
2. Drive the vehicle to an area free of traffic which has a speed limit of at least 40 mph.
CAUTION: The burnishing procedure in step 3 requires frequent stops. The brakes must be allowed to cool between stops while burnishing. With an outdoor temperature of 45~F (7~C) or below allow 0.6 mile between stops, For every 10~F (-12~C) increase in outdoor temperature allow an additional 0.1 mile cooling distance between stops.
3. With vehicle in high gear and traveling 40 mph, brake the vehicle at a smooth, even rate to decrease vehicle speed from 40 mph to 0 in no more than 5 seconds and no less than 4 seconds. Stops which take more than 5 seconds will not burnish the lining fast enough. Stops which take less than 4 seconds might eventually cause overheating. To adequately burnish new brake lining, 40 to 50 stops are required.
PARTS
Description Quantity Part Number
ASSEMBLY, REAR BRAKE 2 3231640
HUB/DRUM (Matched Set)
HUB ASSEMBLY, AR 3238527
FRONT WHEEL
S.R.T. INFORMATION
Operation
Operation Description T.I.C. Number S.R.T.
CO. DRUM, REAR BRAKE - R & R 3-476 3758 0.5
BOTH SIDES
SO. HUB, BRAKE DRUM - REPLACE 3-476 3760 0.8
BOTH SIDES
SO. EXTENDED ROAD TEST 3-476 0130 0.5
(For brake burnishing when brakeshoes are replaced and repair verification)
CO. BEARING AND HUB, FRONT - 3-151 2183 0.8
REPLACE ONE SIDE Includes halfshaft R & R
Filing Instructions
Make reference to this I.S. Note on page 2G-3 of the 1980, 1981 and 1982 AMC Technical Service Manual. File this I.S. Note in the vinyl binder supplied with AMC Supplement 1 of the 1982 Technical Service Manual.