Brake Pressure Regulator Checking & Adjusting

NOTE: On 4000S Quattro, brake pressure regulator is not adjustable.

Regulator is located on rear frame. Empty vehicle, fill fuel tank, and load driver's seat to 165 lbs. (74.8 kg). Bounce rear of car several times, and allow vehicle to settle normally. Firmly depress brake pedal and release quickly. Regulator should have moved.
Measure distance from top of tire rim to lower edge of fender lip (both sides). Install left spring tensioner. Raise vehicle on hoist, and insert right spring tensioner (upper end only). Lower vehicle and bounce rear of car several times. Allow car to settle normally, and attach right spring tensioner to axle.
NOTE: Spring tensioners and measurement are not required if drive-on type hoist is used to support vehicle.

Raise vehicle and check measurement. Adjust if necessary. Connect one 1500 psi (110 kg/cm² ) gauge to left front caliper and another to right rear wheel cylinder (caliper). Bleed gauges, and depress brake pedal firmly several times. Depress brake pedal until front gauge reaches reading listed in table. Check rear gauge reading.

BRAKE PRESSURE REGULATOR PRESSURES (4000)

Application	Front Gauge psi (kg/cm² )	Rear Gauge psi (kg/cm² )
1st Reading	725 (51)	457-566 (32-40)
2nd Reading	1450 (102)	725-914 (51-64)

BRAKE PRESSURE REGULATOR PRESSURES (ALL OTHER MODELS)

Application	Front Gauge psi (kg/cm² )	Rear Gauge psi (kg/cm² )
1st Reading	725 (51)	493-566 (35-40)
2nd Reading	1450 (102)	827-899 (58-63)

If pressures are consistently high at rear gauge, loosen regulator clamp bolt and REDUCE spring tension. If pressures were consistently low, INCREASE spring tension. If specified pressures cannot be obtained after adjustment, replace regulator.

Fig 1: Brake Pressure Regulator Adjustment 4000 regulator is mounted in reverse direction.