Front Brake Pad Replacement

Replacement of front brake pads on the 1965 Mercedes-Benz 220SEb W111, which uses Ate or Teves disc brakes. This procedure requires careful attention to the caliper piston retraction and proper bedding of new pads.

Warnings

Tools required

Parts

• Front brake pad set (4 pads total) × 1 — Ate or Teves original specification, check supplier for W111 fitment
• Anti-squeal shims (if not included with pads) × 1 — May be integrated with pad set
• Brake hardware spring clips × 1 — Often reusable if not damaged

Fluids

• DOT 3 or DOT 4 brake fluid — 0.25 qt

Preparation

1. Park vehicle on level, solid ground and apply parking brake firmly
2. Place wheel chocks behind rear wheels
3. With engine off, pump brake pedal approximately 20 times to depressurize the brake accumulator system
4. Using turkey baster or syringe, remove approximately half the brake fluid from the master cylinder reservoir to prevent overflow when compressing pistons
5. Loosen front wheel lug bolts (19mm) while vehicle is on ground, but do not remove
6. Raise front of vehicle using factory jack points (reinforced areas on rocker panel sills) and support securely on jack stands under front subframe
7. Remove both front wheels completely
8. Verify vehicle stability before working underneath

Procedure

1. 1

   Inspect brake system condition
   With wheel removed, visually inspect the brake disc rotor for scoring, cracks, or excessive wear. Check brake hoses for cracks, bulging, or fluid leaks. Inspect caliper body for cracks or evidence of leaking piston seals (brake fluid weeping). If any of these conditions exist, this job requires additional work beyond pad replacement. The W111 uses single-piston Ate or Teves sliding calipers - verify which type you have by checking manufacturer markings on caliper body.
2. 2

   Remove caliper guide pin bolts
   Locate the two caliper guide pin bolts that secure the caliper to the mounting bracket. These are typically 13mm hex head bolts located at the rear of the caliper assembly. Using a 13mm wrench, loosen and remove both guide pin bolts. Keep these bolts as they will be reused. The caliper may be tight - gently wiggle it if necessary, but do not pry against the rotor surface.
   ⚠Do not lose the guide pin bolts or allow dirt to enter the guide pin bores. Contaminated guide pins cause uneven pad wear and brake binding.
3. 3

   Remove caliper from rotor
   With guide bolts removed, carefully lift the caliper up and away from the brake rotor. The caliper will still be attached to the flexible brake hose - do NOT allow it to hang by the hose weight. Support the caliper by hanging it from the suspension spring with wire or cord, or rest it on the upper control arm. Never let it dangle freely as this can damage the brake hose internally.
4. 4

   Remove old brake pads
   With caliper supported, remove the inner and outer brake pads from the caliper and mounting bracket. Note the orientation and position of any anti-rattle clips, shims, or springs. The W111 calipers typically use a spring clip retainer system - the pads may simply lift out, or you may need to compress small spring clips. Take a photograph or make notes of the exact position of all hardware before removal for correct reassembly.
5. 5

   Clean caliper and mounting bracket
   Using a wire brush and brake cleaner, thoroughly clean the caliper mounting bracket where the pads slide. Remove all rust, old grease, and brake dust. Clean the caliper guide pin bores and guide pins themselves. Pay special attention to the pad abutment surfaces on the mounting bracket - these must be smooth and clean for proper pad movement. Do NOT use petroleum-based solvents. Check that guide pins slide freely in their bores.
6. 6

   Compress caliper piston
   Using a large C-clamp or brake piston compression tool, slowly compress the caliper piston back into its bore. Place the C-clamp so it pushes against the piston face on one side and the back of the caliper body on the other. Compress slowly and steadily - this will push brake fluid back up into the master cylinder reservoir. Watch the reservoir during this process to ensure it doesn't overflow. The piston must be fully retracted to accommodate the thickness of new brake pads.
   ⚠If piston does not compress smoothly or appears seized, the caliper requires rebuild or replacement. Do not force a stuck piston.
7. 7

   Install new brake pads
   Install the new brake pads in the exact same orientation as the old pads were removed. Ensure any anti-rattle clips, shims, or springs are properly positioned exactly as they were originally. The pad with the wear indicator tab (if equipped) typically goes on the inner position. Pads should slide smoothly in the mounting bracket channels. If they bind or stick, clean the mounting surfaces again.
8. 8

   Reinstall caliper over new pads
   Carefully position the caliper over the new brake pads and rotor. Align the guide pin bolt holes with the bores in the mounting bracket. The caliper may need slight pressure to fully seat over the new, thicker pads. Ensure the brake hose is not twisted or kinked during this process.
9. 9

   Install and torque caliper guide bolts
   Insert both caliper guide pin bolts and hand-thread them to avoid cross-threading. Once hand-tight, torque the guide pin bolts to 50-60 ft-lbs (70-80 Nm) using a torque wrench. Tighten in a criss-cross pattern if possible. Verify both bolts are properly seated and tight.
10. 10

    Repeat for opposite side
    Repeat steps 1 through 9 for the opposite front wheel. It is essential to replace brake pads on both front wheels simultaneously to maintain balanced braking. Never replace pads on only one side.
11. 11

    Reinstall wheels
    Reinstall both front wheels, hand-threading all lug bolts first to ensure proper seating. Do not fully tighten lug bolts yet.
12. 12

    Lower vehicle and torque wheels
    Lower vehicle from jack stands until wheels just contact ground but vehicle weight is still on stands. Torque wheel lug bolts to 75-80 ft-lbs (100-110 Nm) in a star pattern. Fully lower vehicle and remove jack stands.
13. 13

    Restore brake pedal pressure
    With engine OFF, slowly pump the brake pedal multiple times until it becomes firm. This seats the caliper pistons against the new pads. The first several pumps will feel soft as the pistons extend - this is normal. Continue pumping until pedal feels firm and consistent. Do NOT start the engine or drive until pedal is firm.
    ⚠️Do NOT attempt to drive the vehicle until brake pedal is firm and holds pressure. Driving with an unpumped brake system will result in no braking on first pedal application.
14. 14

    Check brake fluid level
    Open the hood and check the brake fluid reservoir level. Add DOT 3 or DOT 4 brake fluid to bring level to the MAX mark. The level will be lower than before due to piston extension. Ensure reservoir cap is securely tightened.

Reassembly

1. Ensure all caliper guide bolts are torqued to specification
2. Verify wheel lug bolts are properly torqued in star pattern
3. Confirm brake fluid reservoir is filled to MAX line with proper DOT 3 or DOT 4 fluid
4. Double-check that brake pedal is firm before attempting to move vehicle

Verification

• With engine off, pump brake pedal - it should feel firm and not sink slowly to floor
• Start engine and verify brake warning light (if equipped) is not illuminated
• Perform initial brake test at very low speed (under 5 mph) in safe area to verify brakes engage properly
• Perform gentle stops from 15-20 mph several times to begin bedding-in new pads
• Check for any unusual noises, vibrations, or pulling to one side during braking - any of these indicates a problem requiring immediate attention
• Avoid hard braking for first 100-200 miles to allow proper pad bedding and heat cycling
• After 50 miles of driving, re-check wheel lug bolt torque and brake fluid level
• If brake pedal becomes soft, requires pumping, or brakes feel weak at any time, STOP driving immediately and seek professional service

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