Brake Pads – Checking Pad Thickness and Replacing Pads – 2.5L NA

Overview

This guide covers checking the thickness of brake pads and replacing them on a Porsche 944 with a 2.5L naturally aspirated (NA) engine, for model years 1983–1985.5 (pre-85.5) and 1985.5–1988 (85.5 onwards). Regular inspection ensures safe braking performance, as worn pads can reduce stopping power. Brake pads should be checked every 15,000 miles (24,000 km) or when wheels are removed for maintenance. Replacement is needed when pad thickness reaches 2.5 mm or less, or if the wear indicator light activates.

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Tools Required

• Jack stands
• 19 mm (3/4 inch) socket and ratchet/breaker bar (preferably 1/2″ drive)
• Metric wrench set
• Metric socket set
• Bailing wire or shock cords
• Hammer and flat-tip punch (Pre-85.5)
• Needle nose pliers
• Lineman’s pliers
• Turkey baster or vacuum pump brake bleeder
• Rags
• Small pry bar or large flat-tip screwdriver
• Brake cleaner

Parts Required

• Front brake pads, 477 698 151 A (Pre-85.5) or 944 351 951 00 (85.5 Onwards)
• Rear brake pads, 477 698 151 A (Pre-85.5) or 944 352 951 00 (85.5 Onwards)
• Brake pad wear indicators, 944 612 211 00 (if equipped and worn)
• Vibration damper backing plates or Scotch-3M No. 9485 double-sided adhesive tape (38 mm wide), if not included with pads

Required Additional Procedures

Steps in these procedures are required to complete this process:

• Follow this link to ensure this step – Brake Bleeding – of the process is followed accurately.

Step-by-Step Procedure

Step 1: Check Brake Pad Thickness

1. Loosen the lug nuts on all wheels using a 19 mm (3/4 inch) socket and ratchet or breaker bar, turning them two turns but not removing them.
2. Raise the car and secure it on jack stands.
3. Remove the wheels to access the brake calipers.
4. Visually inspect the brake pads through the caliper. Measure the pad thickness using a ruler or caliper. Replace pads if thickness is 2.5 mm or less, or if the wear indicator light is on.

Step 2: Prepare for Brake Pad Replacement

5. Check the brake fluid reservoir level in the engine compartment. If it’s near the “MAX” mark, remove some fluid using a turkey baster or vacuum pump brake bleeder to prevent overflow during caliper compression.
6. Gather all tools and parts, ensuring you have the correct brake pads for your model: 477 698 151 A for pre-85.5 or 944 351 951 00 (front) and 944 352 951 00 (rear) for 85.5 onwards.

Step 3: Remove Old Brake Pads (Pre-85.5)

7. Remove the cotter pins from the brake pad retaining pins using needle nose pliers.
8. Remove the anti-rattle spring (locking spring) from the retaining pins.
9. Using a hammer and flat-tip punch, drive the retaining pins out of the brake pads and caliper.
10. If equipped, carefully remove the wear pad indicators (wires attached to a pad). Handle gently to avoid breaking the clips.
11. Insert a small pry bar or large flat-tip screwdriver between the old brake pad and the caliper (not the rotor) to press the caliper piston outward. Monitor the brake fluid reservoir level to avoid overflow.
12. Remove the inner and outer brake pads using lineman’s or needle nose pliers.

Step 4: Remove Old Brake Pads (85.5 Onwards)

13. Follow steps 7–12, as the procedure for removing brake pads is identical for 85.5 onwards models with an 8-valve  engine configuration.

Step 5: Clean and Prepare Calipers

14. Clean the calipers and rotors with brake cleaner and rags to remove dust and debris.

Step 6: Install New Brake Pads (Pre-85.5)

15. If provided, attach vibration damper backing plates to the new brake pads. If not provided, use Scotch-3M No. 9485 double-sided adhesive tape (38 mm wide).
16. Insert the new brake pads into the caliper.
17. Insert the brake pad retaining pins and drive them into the fully engaged position using a hammer and flat-tip punch.
18. Install the anti-rattle spring and secure it with cotter pins. Use a flat-tip screwdriver to compress the spring during installation if needed.

Step 7: Install New Brake Pads (85.5 Onwards)

19. Follow steps 15–18, as the installation procedure is identical for 85.5 onwards models with an 8-valve engine configuration.

Step 8: Reassemble and Test

20. Reinstall the wheels and tighten the lug nuts to 130 Nm (96 ft-lbs).
21. Lower the car from the jack stands.
22. Engage the parking brake and consider using wheel chocks for safety.
23. Check the brake fluid reservoir level and fill if necessary.
24. Start the vehicle and pump the brake pedal until it feels firm at its normal height. Do not drive until this is achieved.
25. Recheck the brake fluid level after pumping the brakes.
26. If the brake pedal feels spongy, perform the Brake Bleeding procedure. Follow this link to ensure this step – Brake Bleeding – of the process is followed accurately.
27. Test drive the car for 3–5 miles (5–8 km), making gentle stops initially, then progressively harder stops to seat the brake pads. A burning smell or light smoke is normal during this process.

Post Procedure Checklist

• Verify the brake pedal feels firm and returns to normal height.
• Check the brake fluid reservoir level is within the “MIN” and “MAX” marks.
• Inspect for brake fluid leaks around the calipers.
• Confirm no warning lights (e.g., brake pad wear indicator) are illuminated on the dashboard.
• Ensure the brakes respond effectively during the test drive with no unusual noises or vibrations.

Sources

• Clark’s Garage
• Pelican Parts
• Porsche 944 Workshop Manual, Volume 1
• YouTube