Brake Booster + Master Cylinder Assembly

Restore confident stopping power on your Toyota 4x4 with this vacuum servo and hydraulic master combo. It delivers strong, consistent brake assist for heavy vehicles and towing. Engine vacuum (or pump on diesel) multiplies your foot pressure, while the dual-circuit master sends precise hydraulic force to all wheels. Result: shorter stops, lighter pedal, and safer control on- and off-road .

Why this part is needed

Large SUVs need extra assist to slow down quickly. A healthy booster reduces pedal effort, and a tight-bore master cylinder maintains pressure, improves modulation, and keeps ABS/VSC working right ️.

How it works

A check valve holds vacuum in the booster. When you press the pedal, a diaphragm and reaction valve add assist, and the master cylinder converts force into hydraulic pressure for the front and rear circuits. Seals and precise bores prevent internal bypass and fluid loss.

What happens if it’s broken

Hard pedal, longer braking distance, hissing at the firewall, fluid leaking into the booster, sinking pedal at lights, uneven braking, or rough idle from a vacuum leak. Ignoring these signs risks brake fade and extended stopping distances ⚠️.

Tech notes

Pre-bleed recommended, renew fluid, check the one-way valve and vacuum hose, and transfer the reservoir level sensor if equipped ✅.

Compatibility

• Land Cruiser 100