Parts for your 2001 Daihatsu Gran move-Brake booster

2001 Daihatsu Gran Move brake booster (vacuum servo)

The 2001 Daihatsu Gran Move is fitted with a vacuum-assisted brake booster (often called a brake servo). This is documented in Daihatsu’s factory service information for the Gran Move/Pyzar brake system, which includes procedures for vacuum booster inspection and on‑vehicle testing, and in Daihatsu’s electronic parts catalog listing a “Booster Assy, Brake” mounted between the pedal pushrod and the master cylinder. Those technical sources confirm the booster is a standard component on this model and year.

On this Gran Move, the brake booster’s job is to use engine vacuum to multiply the driver’s pedal effort, so stopping feels light and reassuring rather than heavy and wooden. When the booster and its check valve, hose and grommets are healthy, the car pulls up straight and confidently with predictable pedal feel, whether it’s the school run or a long Kiwi/Aussie motorway stint.

There’s no fixed replacement interval for the booster itself, it’s a “inspect and replace if faulty” unit. As part of regular servicing, a smart check includes looking for perished vacuum hoses, a loose one‑way check valve, and brake fluid weeping from the rear of the master cylinder into the booster—fluid inside the booster is a red flag. A quick “engine‑off, then start” pedal test also helps: several firm pumps with the engine off should harden the pedal, as the engine starts, the pedal should sink slightly as vacuum assist kicks in.

• Common symptoms of trouble:
  • Hard brake pedal and longer stopping distance
  • Hissing from the dash/bonnet area when braking
  • Engine idle changes when the brake is pressed (vacuum leak)
  • Brake warning lamp after related faults or fluid loss
• Service tips:
  • Replace cracked vacuum hose and the check valve as a set if ageing (often around the 10‑year/100,000 km mark).
  • If the master cylinder has leaked into the booster, plan on replacing both—fluid can damage the booster diaphragm.
  • Booster replacement requires disconnecting the pedal clevis inside the cabin and the master cylinder under the bonnet, brakes must be bled afterwards.
  • Use quality gaskets/grommets and verify one‑way valve orientation toward the manifold.

Most boosters aren’t economically rebuildable locally, a new or reman unit is the usual fix. After fitting, a road test and a brake balance check are worthwhile—and for NZ owners, that helps keep WOF inspectors happy.

Popular questions about 2001 Daihatsu Gran Move brake boosters

How can someone tell if the Gran Move’s brake booster is failing?
A failing booster usually shows up as a very firm pedal, extra leg effort, and a longer stopping distance. A steady hiss when the pedal’s pressed or a change in idle speed points to a vacuum leak—often the hose, grommet, or check valve rather than the diaphragm. A simple test is the engine‑off pump test: with the engine off, pump the pedal a few times to exhaust vacuum, hold light pressure and start the engine—the pedal should drop slightly. If it doesn’t, assist may be weak.

Can the original booster be rebuilt, or is replacement the go‑to?
On these cars, replacement is usually the practical route. While diaphragm kits exist in some markets, sourcing correct internal parts and ensuring a safe, sealed rebuild is tricky. If the master cylinder has leaked into the booster, internal damage is common, so a new or reman booster plus a fresh master cylinder is the reliable fix.

Is it safe to keep driving with a dodgy brake booster?
It’ll still stop—hydraulic brakes remain—but pedal effort rises a lot. That can be unsafe in heavy traffic or emergency stops. If there’s a vacuum leak, the engine can run lean or idle erratically, which isn’t great either. Best practice is to minimise driving and book repairs promptly to keep braking performance and roadworthiness (RWC/WOF) on point.