Description
Main brake master cylinder Bosch for Citroën C4, C4 II and Peugeot 307, 308.
Product Overview
High-quality Bosch brake master cylinder designed for Citroën and Peugeot compact models. This direct-fit hydraulic unit restores firm pedal feel and reliable pressure distribution to the braking system. Ideal for professional garages and experienced DIY mechanics who search by part number — common references include 0204254242 and 4601V1. Replacing a worn master cylinder resolves symptoms such as a sinking or spongy brake pedal, internal leaks and loss of braking efficiency.
Key Advantages
- Precision machined components and durable seals for long service life.
- Compatibility with common Citroën/Peugeot brake systems on C4 / C4 II and 307 / 308 models.
- Fast identification by part numbers (handy for workshop parts ordering and inventory).
- Designed to meet the performance demands of modern hydraulic braking systems.
Technical Information
- Manufacturer: Bosch
- Model: Citroën C4, Citroën C4 II, Peugeot 307, Peugeot 308
- Product Codes: 0204254242, 4601R1, 4601T2, 4601V1, 4601V0
- Other Numbers: 204254242 (alternative formatting)
Function And Symptoms Of Failure
The brake master cylinder converts pedal force into hydraulic pressure that operates the calipers and wheel cylinders. Typical failure modes include internal seal wear or collapse, contamination from degraded brake fluid, and corrosion of internal bores. Signs that indicate replacement is required: a gradually sinking brake pedal, a soft or spongy pedal feel, visible fluid leaks at the unit or connections, and uneven braking. Left unaddressed, a failing master cylinder reduces braking performance and can compromise vehicle safety.
Installation Recommendations
Installation should be carried out by a qualified technician or a competent DIYer familiar with brake systems. Basic replacement steps:
- Prepare the vehicle on a level surface and secure it with the parking brake and wheel chocks.
- Remove excess brake fluid from the reservoir using a suitable tool to avoid spills.
- Carefully disconnect brake lines with a flare-nut wrench and cap the lines to prevent contamination.
- Unbolt the master cylinder from the brake booster/firewall and remove the unit.
- Fit the new master cylinder, torque fasteners to manufacturer values, reconnect lines and refill the reservoir with manufacturer-recommended brake fluid.
- Bench-bleed the new unit before installation and perform a full hydraulic bleed of the braking system after fitting to remove air.
- Check for leaks and verify pedal firmness during a low-speed test drive.
Safety Notes: Brake system work affects vehicle safety. Use correct tools, replace contaminated fluid, and follow the vehicle manufacturer’s procedures. If unsure, have the replacement and bleeding done by a professional workshop.
Why This Part Fails Most Often
Master cylinders commonly fail due to ageing seals and contamination. Moisture in brake fluid accelerates internal corrosion and seal deterioration. Over time, abrasive particles and degraded fluid compromise seal surfaces, causing internal leaks and loss of pressure. Heavy or aggressive braking, neglected fluid changes, and prolonged exposure to moisture increase the risk of premature failure.
Compatibility And Searching Tips
This part is frequently searched by the listed part numbers — include 0204254242 and 4601V1 in your lookup to find exact matches. It fits the Citroën C4 (including C4 II) and Peugeot 307 / 308 ranges where this Bosch master cylinder specification is used. Always verify fitment against the vehicle model and year using the part numbers provided.
Final Notes
Choosing a correctly matched Bosch master cylinder ensures reliable braking response and workshop efficiency. Order by part number for fast identification and trust the robust construction to deliver consistent performance under everyday and service conditions.
