Brakes Pads - Bedding In Linings After Installation
85jaguar01DATE . . . OCTOBER, 1985
NUMBER . . . J85/72
MODEL: ALL
SUBJECT: BRAKE JUDDER
KEY POINTS: DRIVING PROCEDURE FOR
CORRECT BEDDING IN OF BRAKES
We take this opportunity to remind dealers of the importance of bedding in new pads or discs when they are fitted to a vehicle. The correct procedure which was detailed in Service Bulletin J85/22 is repeated and amplified:
With the recent introduction of semi-metallic brake linings, it is important that all Service Personnel are aware of the optimum procedure for the "bedding in" of these linings. Details are as follows:
^ In order to ensure optimum brake performance and refinement throughout the life of the brake friction linings and brake discs, it is essential that a controlled brake bedding procedure is undertaken during the early life of the friction linings.
^ The procedure used should ensure that the friction linings quickly achieve normal operating conditions as a result of low energy applications, without being subjected to high energy input levels.
^ The procedure recommended for the first 200 miles is of deliberate, frequent, light application wherever possible, similar to that used during normal town driving. On open road driving, the above conditions have to be simulated. Try NOT to brake from speeds in excess of 60 mph, reduce speed by short applications, i.e. 50-40 mph at intervals or approximately 1 mile.
This procedure will ensure satisfactory brake lining/disc conditioning and lead to optimum brake life and performance.
In addition, certain climatic conditions can contribute to brake judder. For example, vehicles used in a high humidity climate and left standing for periods of a week or more will exhibit brake judder due to minor surface corrosion which may have occurred. Also, the following components have been found to contribute to brake judder, if they are not up to specification or wear has taken place:
A) upper and lower ball joints
B) steering rack bushes
C) upper wishbone bushes
D) front hub bearings
Please delete Service Bulletin J85/22, since this replaces it.