GM Service Manual Online
For 1990-2009 cars only

Component Specifications Brake Systems

System

Master Cylinder Dia.

Front Brakes (Disc)

Rear Brakes (Drum)

Rear Brakes (Disc)

Brake Assist

JB7

31.8 mm

1.25 in

318.8x39.3 mm

12.50×1.54 in

331.5x64 mm

13.00×2.5 in

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Hydraulic Hydro-Boost

JB8

31.8 mm

1.25 in

318.8x39.3 mm

12.50×1.54 in

331.5x89.3 mm

13.00×3.50 in

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Hydraulic Hydro-Boost

JF9

40.00 mm

1.57 in

357.0x36.7 mm

14.00×1.44 in

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936.2x36.7 mm

13.60×1.44 in

Hydraulic Hydro-Boost

Component Specifications Rotor Thickness

Original

Maximum Refinish

Replacement (Discard)

32.51 mm (1.28 in)

31.25 mm (1.23 in)

30.86 mm (1.215 in)

39.11 mm (1.54 in)

37.59 mm (1.48 in)

37.21 mm (1.456 in)

Component Specifications Bendix Caliper Replacement Key

Bumper Gap

Replacement Key

P/N

0.0-0.060 in

Std. Size-I

14023439

0.061-0.100 in

0.040 Oversize-II

14026793

0.101-0.140 in

0.080 Oversize-II

14026794

0.141-0.180 in

0.120 Oversize-III

14026795

0.181-0.220 in

0.160 Oversize

14026796

0.221 in

Replace Caliper and Anchor Plate or Steering Knuckle

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Component Specifications Shim Selection

Gap Measurement

0.0-1.47 mm

(0.0-0.058 in)

1.50-2.57 mm

(0.059-0.101 in)

2.59-3.68 mm

(0.102-0.145 in)

Shim Thickness

No Shim

0.64 mm

(0.025 in)

1.14 mm

(0.045 in)

Component Specifications Dimensional

Dimensional

Application

Metric

English

Brake Lining Replacement Thickness

1.60 mm

0.063 in

Brake Lining to Brake Rotor Maximum Clearance

0.13 mm

0.005 in

Brake Rotor OD Runout

0.76 mm

0.030 in

Brake Rotor Thickness Variation

0.05 mm

0.002 in

Brake Rotor Total Indicated Runout (TIR)

0.13 mm

0.005 in

Rear Hub and Bearing Assembly Lateral Runout

0.040 mm

0.0016 in