Brakes - Rotor and Drum Inspection Criteria
91mazda03
Bulletin No. 003/91
Issued 10/9/91
Revised
Category P
Applicable Model/s All Models 1989-'92
Subject: BRAKE ROTOR/DRUM
INSPECTION CRITERIA
DESCRIPTION
When inspecting the brake rotor or drum for wear, refer to the following to detemine if a rotor/drum can be resurfaced by machining.
INSPECTION PROCEDURE
Brake Rotor Inspection:
Many rotors have been replaced unnecessarily for brake noise. If the rotors do not contain cracks or deep grooves, and the remaining rotor thickness allows for machining, the rotors should be resurfaced.
NOTE:
Minimum allowed rotor thickness is stamped on rotor surface.
Rotor Thickness Specification:
MPV 1992
4X2
New 30.0 mm (1.18 in)
Minimum 28.0 mm (1.10 in)
4X4
New 28.0 mm (1.10 in)
Minimum 26.0 mm (1.02 in)
MPV 1989-'91
4X2 & 4X4
New 24.0 mm (0.94 in)
Minimum 22.0 mm (0.87 in)
B-Series 1989-'92
4X4
New 22.0 mm (0.87 in)
Minimum 20.0 mm (0.79 in)
4X2
New 20.0 mm (0.79 in)
Minimum 18.0 mm (0.71 in)
Navajo 1991-'92
New 24.9 mm (0.98 in)
Minimum 20.6 mm (0.81 in)
323/Protege
(Front) 1990-'92
New 22.0 mm (0.87 in)
Minimum 20.0 mm (0.79 in)
(Front) 1989
New 18.0 mm (0.71 in)
Minimum 16.0 mm (0.63 in)
(Rear) 1989-'92
New 9.0 mm (0.35 in)
Minimum 7.0 mm (0.28 in)
(Rear) 1989
New 10.0 mm (0.39 in)
Minimum 8.0 mm (0.31 in)
MX-3 1992
(Front)
New 22.0 mm (0.87 in)
Minimum 20.0 mm (0.79 in)
(Rear)
New 9.0 mm (0.35 in)
Minimum 8.0 mm (0.31 in)
626/MX-6 1989-'92
(Front)
New 24.0 mm (0.94 in)
Minimum 22.0 mm (0.87 in)
(Rear)
New 10.0 mm (0.39 in)
Minimum 8.0 mm (0.31 in)
MX-5 1990-'92
(Front)
New 18.0 mm (0.71 in)
Minimum 16.0 mm (0.63 in)
(Rear)
New 9.0 mm (0.35 in)
Minimum 7.0 mm (0.28 in)
RX-7 1989-'91
(Front)
New 22.0 mm (0.87 in)
Minimum 20.0 mm (0.79 in)
(Rear Solid)
New 10.0 mm (0.39 in)
Minimum 8.0 mm (0.31 in)
(Rear Ventilated)
New 20.0 mm (0.79 in)
Minimum 18.0 mm (0.71 in)
Rotor Thickness Specification (Cont.)
929 (Front) 1992
New .................. 24.0 mm (0.94 in)
Minimum .............. 22.0 mm (0.87 in)
(Front) 1989-'91
New .................. 22.0 mm (0.87 in)
Minimum .............. 20.0 mm (0.79 in)
(Rear) 1990-'92
New .................. 18.0 mm (0.71 in)
Minimum .............. 16.0 mm (0.63 in)
(Rear) 1989
New .................. 10.0 mm (0.39 in)
Minimum .............. 8.0 mm (0.31 in)
Brake Drum Inspection:
Most brake drums DO NOT require replacement. Only drums containing deep grooves or blue (hot) spots should be replaced. Drums not showing these signs should be resurfaced by means of machining as long as the maximum inside diameter is not exceeded.
NOTE:
Maximum allowed drum inside diameter is stamped on the exterior drum surface.
Brake Drum Specification:
MPV 1989-'92
Inside Diameter (New) ... 260.0 mm (10.24 in)
Inside Diameter (Max.) .. 261.5 mm (10.30 in)
B-Series 1989-'92
Inside Diameter (New) ... 260.0 mm (10.24 in)
Inside Diameter (Max.) .. 261.5 mm (10.30 in)
Navajo 1991-'92
Inside Diameter (Max.) .. 256.3 mm (10.09 in)
323/Protege' 1989 & '92
Inside Diameter (New) ... 200.0 mm (7.87 in)
Inside Diameter (Max.) .. 201.0 mm (7.91 in)
323/Protege' 1990 & '91
Inside Diameter (New) ... 228.6 mm (9.00 in)
Inside Diameter (Max.) .. 229.6 mm (9.04 in)
MX-3 1992
Inside Diameter (New) ... 200.0 mm (7.87 in)
Inside Diameter (Max.) .. 201.0 mm (7.91 in)
626/MX-6 1989-'92
Inside Diameter (New) ... 228.6 mm (9.00 in)
Inside Diameter (Max.) .. 230.1 mm (9.06 in)