Brake master cylinder Citroën Peugeot 321372 1616905480 1638051480

Descrizione

BOSCH brake master cylinder for Stellantis vehicles
From a vehicle with 33,000 km mileage

Part description

Used BOSCH brake master cylinder for Citroën, Peugeot and other models listed in the documentation. In the braking system, it converts the force applied to the pedal into the hydraulic pressure required to operate the brakes. Its proper function is essential for safe and reliable braking.

The part comes from a vehicle with the stated mileage of 33,000 km and offers a replacement option for a faulty cylinder when repairing the braking system. The identifiers 321372, 1616905480 and 1638051480 are important when selecting the part. Before ordering, compare the numbers and design with the original part; the model name alone does not guarantee that the braking system design matches.

Technical information

• Manufacturer: BOSCH
• Model: Citroën Berlingo K9, FIAT DOBLO III, OPEL COMBO E K9, PEUGEOT PARTNER III, PEUGEOT RIFTER
• Additional numbers: 321372, 1616905480, 1638051480
• Part type: brake master cylinder
• Condition: used part
• Donor vehicle mileage: 33,000 km
• Model years and engine variants: not specified

Product codes

• Product codes: 321372, 1616905480, 1638051480

When looking for a replacement brake master cylinder, compare the codes listed above with the markings on the removed part and the vehicle’s technical documentation.

Installation recommendations

The following procedure is a general guide to replacing a brake master cylinder. The exact steps, bleeding method and specified installation requirements depend on the specific model and vehicle configuration. This is a safety-critical component; have a qualified mechanic install it if you do not have the necessary experience and equipment.

1) Before installation

• Compare the markings, body shape, mounting points, number and design of the hydraulic connections, and connection to the reservoir with the original cylinder.
• Check the body, threads and mating surfaces. The part must not have cracks, damaged threads, significant corrosion or obvious signs of leakage.
• Check that the openings are clean and protected against dirt. A visual inspection alone does not confirm the cylinder’s internal sealing or proper operation.
• Check the cause of the fault before replacing the part. A soft or sinking pedal may also be caused by another leak or air in the system.

2) Tools and materials required

• Standard installation tools, suitable brake line wrenches and a torque wrench.
• Equipment for safely collecting fluid and protective plugs for hydraulic openings.
• Equipment for bleeding the braking system in accordance with the vehicle’s service procedure.
• Clean, lint-free materials, protective gloves and eye protection.
• Brake fluid and any seals specified by the manufacturer of the particular vehicle; their specifications are not provided in the documentation.

3) Step-by-step installation procedure

1. Secure the vehicle safely against movement and prepare the work area. Protect painted surfaces from contact with brake fluid.
2. Following the service documentation, gain access to the cylinder and carry out the required safety measures for working on the braking system.
3. Clean the area around the cylinder and all connections to be disconnected to prevent dirt from entering the hydraulic circuit.
4. Record the routing and connection of each line. Handle the fluid in the reservoir according to the manufacturer’s procedure and prevent uncontrolled spillage.
5. Carefully disconnect the brake lines using a suitable wrench. Do not strain the pipes by bending them, and immediately protect the open ends with clean plugs.
6. Disconnect any other components that prevent removal, release the fasteners and remove the original cylinder without using force.
7. Inspect the mating surfaces and adjacent components. Have any traces of fluid around the connection to the brake booster professionally assessed and eliminate the cause of the leak.
8. Prepare the replacement cylinder according to the vehicle manufacturer’s instructions. If pre-filling or pre-bleeding is specified, carry it out as directed. Transfer the reservoir, if applicable, only when the design allows it.
9. Position the cylinder without placing it under tension and secure it in accordance with the service specifications. Connect the hydraulic lines; start the threads by hand to avoid cross-threading.
10. Reconnect all disconnected connections, top up with the specified fluid and bleed the system in the sequence specified by the manufacturer. Do not allow the reservoir to run dry during bleeding. If the procedure requires diagnostic activation of the hydraulic unit, use the appropriate equipment.
11. Check all connections for leaks, check the fluid level and verify pedal operation. Reinstall any covers and other components that were removed.

4) Post-installation checks and function verification

• With the vehicle stationary, check for appropriate pedal resistance and make sure the pedal does not gradually sink unusually when constant pressure is applied.
• With the pedal depressed, inspect the connections and the area around the cylinder again. There must be no fluid leaks.
• If the pedal is soft, sinks, or a braking system fault appears, do not drive the vehicle and rectify the fault first.
• After the static checks have been completed successfully, test the braking performance on a test bench and, if appropriate, take a short test drive at low speed in a safe area. Then check the system again for leaks and verify the fluid level.

5) Most common installation errors and how to prevent them

• Installing the wrong cylinder variant: compare the codes, mounting points and all connections before installation.
• Contaminating the circuit: work cleanly and keep capping open lines as you go.
• Damaging threads or brake pipes: use suitable wrenches, start connections by hand and do not force lines into the wrong position.
• Incomplete bleeding: follow the procedure for the specific vehicle, including any diagnostic operations that may be required.
• Using unsuitable or contaminated fluid: use only fluid that meets the manufacturer’s specifications and do not return collected fluid to the system.
• Replacing the part without addressing the actual cause of the fault: check the other parts of the braking system and their seals as well.

Reasons why the part becomes damaged

Brake master cylinders can generally fail due to ageing seals, wear of internal surfaces or contamination of the hydraulic system. The causes listed below do not describe the condition found in the item being offered.

• Ageing and wear of the seals: this can cause an external fluid leak or internal pressure bypass.
• Neglected brake fluid maintenance: moisture in the fluid promotes corrosion of internal system components.
• Dirt in the hydraulic circuit: this can damage sealing surfaces and impair the cylinder’s proper operation.
• Unsuitable fluid or contamination: this can damage the seals and cause leaks.
• Incorrect installation or handling: excessive strain on connections, damaged threads or the ingress of dirt can render the part unusable.
• Unsuitable storage: unprotected openings allow moisture and dirt to enter.