Parts for your 1998 Daihatsu Gran move-Brake booster

1998 Daihatsu Gran Move Brake Booster

Based on factory-style references, the 1998 Daihatsu Gran Move (also known as Pyzar, G303/G313 series) is fitted with a vacuum-operated brake booster. The Daihatsu Electronic Parts Catalogue lists a dedicated brake booster (servo) assembly for these models, and the Daihatsu service manual (Brake/Chassis section) details vacuum booster operation and testing procedures, including the one-way check valve and vacuum hose routing from the intake manifold. Aftermarket catalogues used by workshops in Australia and New Zealand also stock a direct-fit booster unit for the 1996–2000 Gran Move range, confirming it’s a standard part of the braking system.

On this Gran Move, the brake booster’s job is to use engine vacuum to multiply the force a driver applies to the pedal. That means easier, more confident stops without stamping on the brakes. It sits on the firewall behind the master cylinder and uses a check valve and vacuum hose to hold vacuum even after the engine’s switched off for a bit.

As part of routine servicing, it’s worth a quick booster health check. With the engine off, pump the pedal a few times to deplete vacuum, hold pressure, then start the engine—if the booster’s good, the pedal should sink slightly as vacuum assist returns. Also give the vacuum hose a once-over for cracks, make sure the hose clamps are snug, and listen for a faint hiss around the pedal or firewall that could hint at a vacuum leak. Any brake fluid weeping from the back of the master cylinder should be sorted immediately, as fluid can damage the booster diaphragm.

Typical symptoms of a dodgy booster include a hard brake pedal, more pedal effort than usual, longer stopping distances, or a constant hiss while braking. If any of these pop up, it’s time to test the booster and check valve properly.

Replacement is straightforward for an experienced tech: the master cylinder can usually be unbolted and swung aside carefully, the booster removed from the firewall, and the pushrod length set to spec before refitting. If the brake lines are opened, the system will need bleeding. Always renew the check valve grommet if it’s perished, and ensure the vacuum hose seals tight on refit. There’s no fixed replacement interval—just inspect at service time and replace if the diaphragm, check valve, or hose shows signs of failure. On ABS and non-ABS Gran Move variants alike, a healthy booster makes the pedal feel consistent and confidence-inspiring.

• Watch-outs: hard pedal, hissing noise, fluid at master/booster join, rough-idle vacuum leaks.
• Good practice: test the check valve one-way function and replace aged vacuum hose.

Popular questions about 1998 Daihatsu Gran Move brake boosters

How can someone quickly test the brake booster at home?
With the engine off, pump the pedal a few times to use up stored vacuum. Hold firm pressure on the pedal and start the engine. If the booster’s working, the pedal should drop a little under your foot. If it stays rock hard, check the vacuum hose and one-way valve before condemning the booster itself.

What are the tell-tale signs the booster or check valve is failing?
Expect a harder-than-normal pedal, more effort to stop, a whooshing or hissing noise near the pedal or firewall, and possibly a rough idle if there’s a big vacuum leak. If brake fluid has leaked from the master cylinder into the booster, pedal feel can get inconsistent and the booster may eventually fail.

Is it safe to drive if the booster has failed?
The brakes will still work mechanically, but pedal effort will be high and stopping distances can increase, especially in an emergency. It’s not recommended to keep driving like that. If a leak is causing rough running, it’s best to fix it straight away to avoid compounding issues.