Removing and installing brake master cylinder, Audi S1: Audi A1

🧭 Before you start

Unscrew the brake lines and seal them immediately, unplug the brake light switch and remove the nuts holding the master cylinder to the servo. Transfer the heat shield and brake light switch. Refit with the pushrod correctly located, using an assistant on the pedal if needed, then fit a new O-ring and nuts and reinstall the switch and reservoir before bleeding.

Fits: Audi A1 (8X, 2010–2018)

• Opens: brake fluid
• Renewed: o-ring

Don't miss

• Plug open brake connections immediately with clean sealing plugs to keep dirt and moisture out.
• Do not let brake fluid enter the brake servo; it damages the servo diaphragm.
• Check the servo pushrod sits correctly in the master cylinder before tightening the nuts.
• Renew the O-ring and the nuts after removal.
• Never suck brake fluid through a hose; wear chemical-resistant gloves.

Written for this job from the workshop steps below · TorqFix editorial.

📋 Procedure

1. ⚠ Health risk!Brake fluid is poisonous and must NOT be drawn off by sucking through a hose.Always wear chemical-resistant protective gloves to prevent brake fluid from contacting skin.Always observe the relevant environmental regulations for disposal.Risk of malfunction if brake fluid comes into contact with fluids containing mineral oils.Do not under any circumstances allow brake fluid to come into contact with fluids that contain mineral oils (e.g. oil, petrol, cleaning agents). Protective gloves must be free of oil and grease.Risk of damage to paintwork surfacesDue to its corrosive effect, brake fluid must not be allowed to come into contact with paintwork. Rinse off brake fluid spillages immediately using plenty of water. — Remove brake fluid reservoir . [Note: To protect against escaping brake fluid, place a sufficient number of lint-free cloths in area beneath brake master cylinder.]
2. Unscrew union screws (arrows) and detach brake lines (1, 2).
3. Seal open connections immediately using clean sealing plugs from repair kit1H0 698 311 A.
4. Unplug electrical connector for brake light switchF and move electrical wire clear.
5. Remove nuts (arrows) and detach brake master cylinder (1) from brake servo.

6. If fitted, remove heat shield.
7. Remove brake light switch . [Note: Renew O-ring and nuts after removal.]
8. ⚠ Risk of damage to brake servoBrake fluid must not be allowed to enter the brake servo. — When fitting brake master cylinder (1), make sure that push rod (3) is correctly positioned in brake servo (2).
9. If originally fitted, install heat shield.
10. If necessary, have a second mechanic depress brake pedal slightly to facilitate insertion of brake master cylinder in pushrod.
11. Install brake light switch .
12. Install brake fluid reservoir .

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