Parts for your 2021 Mitsubishi Eclipse cross-Brake booster

2021 Mitsubishi Eclipse Cross Brake Booster

Yes, the 2021 Mitsubishi Eclipse Cross is fitted with a power-assisted brake booster (vacuum type). This is documented in Mitsubishi Motors’ Service Manual for Eclipse Cross (GK/GL, Group 35A – Brakes: Power brake unit, vacuum type), the Mitsubishi ASA electronic parts catalogue (listing “Servo, brake (power), vacuum type” for MY2021), and the 2021 Owner’s Manual section describing the power brake system and its behaviour if the engine is off. For the PHEV variant, Mitsubishi technical literature notes an electric vacuum pump that maintains booster vacuum during EV driving, but the booster itself remains a vacuum servo.

On this model, the brake booster’s job is to multiply pedal effort using engine manifold vacuum (and, on PHEV, an electric vacuum pump), so the driver gets strong, consistent braking with a light press. It works in tandem with ABS and stability systems to keep stops smooth and controlled across city commutes and country kilometres.

The booster isn’t a routine replacement item, but it should be checked at every service. A technician will inspect the vacuum hose and one-way check valve, look for any fluid weep at the master cylinder-to-booster joint, and listen for a faint hissing that can hint at a diaphragm leak. Brake fluid should be flushed about every 24 months to protect the hydraulic side that the booster assists.

• Hard brake pedal and longer stopping distances
• Hissing from the driver’s side firewall area
• Engine idle flare or lean codes from a vacuum leak
• Pedal that sinks slowly if the booster’s internal valve is faulty

A quick at-home check: with the engine off, press the pedal a few times to deplete vacuum, hold light pressure, then start the engine. If the pedal drops slightly, the booster has assist. If it stays rock-hard or there’s audible hissing, book it in.

If replacement’s needed, it’s best handled by a qualified workshop. The job typically involves separating the master cylinder, transferring the pushrod clevis at the pedal, renewing the vacuum hose and check valve grommet, and then bleeding the brakes and road testing. OEM or high-quality parts are recommended, and technicians will set pedal free-play and the brake light switch correctly. On the PHEV, they’ll also verify the electric vacuum pump operation and related hoses.

Look after the vacuum hose, check valve, and fluid, and the Eclipse Cross brake booster should deliver years of reliable, confidence-inspiring stopping.

Popular questions

Does the 2021 Eclipse Cross have a brake booster?
Yes. All 2021 Eclipse Cross variants use a vacuum brake booster. The PHEV adds an electric vacuum pump so braking assistance remains available during EV-only running.

What are the signs a brake booster is failing on an Eclipse Cross?
Expect a firmer-than-normal pedal, longer stopping distances, and sometimes a hissing noise at the firewall. You might also notice a high or unstable idle due to a vacuum leak. If the pedal is very hard, don’t keep driving—have it inspected.

Is the brake booster a service item or only replaced when faulty?
It’s inspected at regular services but not replaced on a time or kilometre interval. Workshops focus on the vacuum hose, check valve, grommets, and any fluid traces. Replacement is only done if faults are found.