Parts for your 1998 Mitsubishi Lancer-Brake booster

1998 Mitsubishi Lancer Brake Booster

The 1998 Mitsubishi Lancer is fitted with a vacuum-assisted brake booster (also called a brake servo). This is documented in factory and aftermarket manuals: Mitsubishi Motors Lancer CE/CK Service Manual, Group 35A Brakes (vacuum-type power brake unit), Haynes Repair Manual for Mitsubishi Mirage & Lancer 1997–2002, and Gregory’s Service and Repair Manual for Mitsubishi Lancer CE 1996–2003. So, yes—on a ’98 Lancer the brake booster is absolutely relevant and part of the standard braking system.

On this model, the brake booster sits on the firewall behind the engine bay, with the master cylinder bolted to its front. Its job is to use engine vacuum to multiply the force from the driver’s foot, giving a lighter pedal and more consistent stopping power. If the booster or its one-way check valve leaks, the pedal can go rock-hard, braking distances can blow out, and you might hear a faint hiss from under the dash or notice a rough idle when pressing the pedal.

As part of routine servicing on a 1998 Mitsubishi Lancer, it’s smart to give the booster and vacuum hose a once-over. Look for perished rubber, oil contamination, or a loose grommet at the booster inlet. A quick driveway test helps too: with the engine off, pump the brake pedal a few times until it firms up, hold light pressure, then start the engine. If the pedal sinks slightly, the booster is getting vacuum assist as it should.

• If the pedal stays hard after starting, check the vacuum hose and one-way valve first.
• If there’s a persistent hiss or poor assist even with a good vacuum supply, the booster diaphragm may be failing.
• A sinking pedal under steady pressure usually points to the master cylinder, not the booster.

When replacement is due, a quality new or remanufactured unit is the go. The master cylinder often needs to be unbolted from the booster—protect paintwork from any brake fluid. If lines are opened, bleed the system afterwards. Under the dash, the clevis pin at the pedal comes out, and the booster unbolts from the firewall. Set the pushrod length to spec per the service manual to avoid drag or a long pedal. Don’t spray solvents into the booster, if it’s contaminated or leaking, replace it. After fitting, road-test somewhere safe to confirm pedal feel and braking balance. That’s one more job sorted before the next few thousand kilometres around Aus or Aotearoa.

Popular questions about 1998 Mitsubishi Lancer brake boosters

Does a 1998 Lancer have a brake booster?
Yes. All mainstream 1998 Lancer petrol variants for AU/NZ use a vacuum brake booster mounted on the firewall. It works with manifold vacuum and a check valve to reduce pedal effort and improve stopping consistency.

What are the signs the brake booster is failing?
A very hard pedal, longer stopping distances, a hissing noise when pressing the brake, or a change in idle quality with the pedal applied are common signs. Always rule out vacuum hose or check-valve faults before calling the booster itself.

Can it be driven with a faulty booster?
Technically yes, but it’s unsafe—pedal effort goes up dramatically. It’s best to organise repairs straight away and avoid heavy traffic or high-speed driving until it’s sorted.