Audi Audi S4 1991-1994 Brakes Specifications
Detailed technical specifications and service information for the 1991-1994 Audi S4 braking system. Includes brake components, torque values, fluid requirements, and ABS system details.
Overview Specifications
Comprehensive description of the brakes specifications for the 1991-1994 Audi S4, including key features, measurements, and technical details. This section covers the braking system's design, components, and performance specifications.
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Use the search function to locate specific brake specifications by entering keywords such as 'rotor diameter', 'pad material', or 'caliper type'.
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Key Specifications
Front Rotor Diameter
280 mm
Rear Rotor Diameter
245 mm
Brake Fluid Type
DOT 4
Front Pad Minimum Thickness
3 mm
Stopping Distance (60-0 mph)
120 feet
Available Specifications
Brake System Overview
This section provides an overview of the Audi S4's braking system, including its design, components, and key features.
Brake System Overview
This section provides an overview of the Audi S4's braking system, including its design, components, and key features.
Brake System Design
- Dual-circuit hydraulic braking system with diagonal split
- Front and rear disc brakes with ventilated front rotors
- Anti-lock Braking System (ABS) as standard
- Brake booster for enhanced pedal feel
Brake Components
- Front brake rotors: 280 mm diameter, 22 mm thickness
- Rear brake rotors: 245 mm diameter, 10 mm thickness
- Front calipers: 4-piston fixed design
- Rear calipers: Single-piston floating design
- Brake pad material: Semi-metallic compound
Note: Brake pad material may vary depending on the market and optional performance packages.
Brake Performance Specifications
This section details the performance specifications of the Audi S4's braking system, including stopping distances and pedal force requirements.
Brake Performance Specifications
This section details the performance specifications of the Audi S4's braking system, including stopping distances and pedal force requirements.
Stopping Distance
- 60 mph to 0 mph: 120 feet (36.6 meters)
- 80 mph to 0 mph: 210 feet (64 meters)
- 100 mph to 0 mph: 320 feet (97.5 meters)
Pedal Force and Travel
- Pedal force required for full braking: 70-80 lbs (31.8-36.3 kg)
- Pedal travel: 1.5-2 inches (38-50 mm)
- Brake fluid type: DOT 4
- Brake fluid capacity: 0.5 liters
Maintenance and Service
This section covers maintenance intervals, inspection procedures, and replacement specifications for the Audi S4's braking system.
Maintenance and Service
This section covers maintenance intervals, inspection procedures, and replacement specifications for the Audi S4's braking system.
Brake Pad Replacement
- Front pad minimum thickness: 3 mm
- Rear pad minimum thickness: 2 mm
- Recommended replacement interval: 30,000-50,000 miles (48,000-80,000 km)
- Torque specification for caliper bolts: 25-30 Nm
Rotor Inspection and Replacement
- Front rotor minimum thickness: 20 mm
- Rear rotor minimum thickness: 8 mm
- Rotor runout limit: 0.05 mm
- Rotor replacement interval: 60,000-80,000 miles (96,000-128,000 km)
Note: Rotor replacement intervals may vary based on driving conditions and usage.
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Brakes Specifications
Brake System Type
- System
- Hydraulic dual-circuit with vacuum booster
- Front Brakes
- Ventilated discs
- Rear Brakes
- Solid discs
- Parking Brake
- Mechanical, rear drum-in-disc
Front Brake Specs
- Disc Diameter
- 280 mm
- Disc Thickness
- 22 mm
- Min Thickness
- 20 mm
- Caliper Type
- Single-piston floating
- Pad Material
- Semi-metallic
- Part Number
- 8A0615101A
Rear Brake Specs
- Disc Diameter
- 245 mm
- Disc Thickness
- 10 mm
- Min Thickness
- 8.5 mm
- Caliper Type
- Single-piston floating
- Pad Material
- Semi-metallic
- Part Number
- 8A0615601B
Parking Brake Specs
- Drum Diameter
- 180 mm
- Shoe Width
- 30 mm
- Adjustment Type
- Manual
- Part Number
- 8A0615601C
Brake Fluid Specs
- Type
- DOT 4
- Capacity
- 1.0 liter
- Boiling Point
- 230°C (dry), 155°C (wet)
- Replacement interval
- Every 2 years or 30,000 miles
Brake Line Specs
- Material
- Steel braided with rubber coating
- Front Line Diameter
- 4.75 mm
- Rear Line Diameter
- 4.75 mm
- Pressure Rating
- 2000 psi
Brake Booster Specs
- Type
- Vacuum-assisted
- Diameter
- 9 inches
- Part Number
- 8A0612101D
- Operating Pressure
- 18-22 inHg
Brake Pedal Specs
- Pedal Ratio
- 4.2:1
- Free Play
- 5-10 mm
- Travel
- 50-60 mm
- Force Required
- 30-50 lbs
Brake Wear Limits
- Front Pad Min Thickness
- 3 mm
- Rear Pad Min Thickness
- 3 mm
- Front Disc Min Thickness
- 20 mm
- Rear Disc Min Thickness
- 8.5 mm
- Parking Brake Shoe Min Thickness
- 1.5 mm
Brake Diagnostic Specs
- Pedal Firmness Test
- Pedal should not sink under constant pressure
- Fluid Level Check
- Between MIN and MAX marks on reservoir
- Leak Test
- No visible leaks at calipers, lines, or master cylinder
- Noise inspection
- Check for squealing, grinding, or uneven wear
Brake Maintenance Specs
- Pad Replacement interval
- Every 30,000-50,000 miles
- Disc Resurfacing Limit
- 0.5 mm maximum
- Fluid Flush interval
- Every 2 years or 30,000 miles
- Parking Brake Adjustment Interval
- Every 15,000 miles
Service Information Service
Detailed service requirements and schedules for the 1991-1994 Audi S4 braking system
- Inspect brake pads and discs for wear
- Check brake fluid level and condition
- Inspect brake lines for leaks or damage
- Adjust parking brake if necessary
Perform visual inspection and adjust as needed
- Replace brake fluid
- Inspect and resurface brake discs if necessary
- Check brake booster operation
- Inspect calipers for proper function
Fluid replacement is mandatory at this interval
- Replace front and rear brake pads
- Inspect and replace brake discs if below minimum thickness
- Check parking brake shoes and adjust
- Inspect brake lines and replace if corroded
Full brake system inspection and component replacement as needed
Frequently Asked Questions
Find answers to common questions about torque specifications
Q1 What is the brake rotor diameter and thickness for the 1991-1994 Audi S4?
What is the brake rotor diameter and thickness for the 1991-1994 Audi S4?
The front brake rotors for the 1991-1994 Audi S4 have a diameter of 276 mm and a thickness of 25 mm. The rear brake rotors have a diameter of 245 mm and a thickness of 10 mm. Always measure rotor thickness before replacement to ensure it meets minimum specifications.
Q2 What type of brake fluid is recommended for the Audi S4?
What type of brake fluid is recommended for the Audi S4?
The 1991-1994 Audi S4 requires DOT 4 brake fluid with a minimum dry boiling point of 230°C (446°F) and a wet boiling point of 155°C (311°F). Always use fresh, unopened brake fluid to avoid contamination and ensure proper brake system performance.
Q3 How often should the brake pads be replaced on the Audi S4?
How often should the brake pads be replaced on the Audi S4?
Brake pad replacement intervals vary based on driving conditions, but typically, front brake pads should be inspected every 15,000 miles and replaced when worn to 3 mm or less. Rear brake pads generally last longer but should also be inspected regularly.
Q4 What is the proper procedure for bleeding the brake system on the Audi S4?
What is the proper procedure for bleeding the brake system on the Audi S4?
The brake system should be bled using a pressure bleeder or manual bleeding method, starting with the wheel farthest from the master cylinder (rear right) and moving to the closest (front left). Use only DOT 4 brake fluid and ensure no air remains in the system to maintain braking efficiency.
Q5 Are there any specific torque specifications for brake caliper bolts?
Are there any specific torque specifications for brake caliper bolts?
Yes, the front brake caliper mounting bolts should be torqued to 85 Nm (63 lb-ft), and the rear brake caliper mounting bolts should be torqued to 35 Nm (26 lb-ft). Always use a calibrated torque wrench and follow Audi's recommended tightening sequence.
Factory Service Resources
Access official service manuals, technical documents, and repair guides. These resources provide detailed procedures, specifications, and diagrams directly from the manufacturer.
Audi S4 Brake System Service Manual
Coming SoonOfficial Audi service manual detailing brake system maintenance, repair procedures, and specifications for the 1991-1994 S4.
Brake Pad and Rotor Replacement Guide
Coming SoonStep-by-step guide for replacing brake pads and rotors on the 1991-1994 Audi S4, including torque specifications and safety precautions.
Brake Fluid Selection and Bleeding Procedure
Coming SoonDetailed instructions on selecting the correct brake fluid and bleeding the brake system for optimal performance.
Audi S4 Brake System Troubleshooting
Coming SoonCommon brake system issues and solutions for the 1991-1994 Audi S4, including noise, vibration, and reduced braking efficiency.
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