Load-Sensing Proportioning Valve Test

Before diagnosing Load-Sensing Proportioning Valve (LSPV), ensure all other brake components are operating properly. When all other brake system components are determined to be okay, perform LSPV test beginning with next step.
Ensure unladen vehicle is on level ground. Ensure lever is not contacting stopper bolt. See Fig 1.
When lever is pushed toward valve, distance from LSPV lever hole and support hole must be within specification. See LOAD-SENSING SPRING LENGTH table under ADJUSTMENTS. If measured distance is not within specification, loosen support bolt. Adjust support until measured distance is within specification.
After measured distance is within specification, connect pressure gauges to input and output ports of LSPV. See Fig 2. Bleed brake system. See BRAKE BLEEDING in this article.
Remove LSPV load-sensing spring. Slowly depress brake pedal. Check readings on pressure gauges. See LSPV PRESSURE SPECIFICATIONS table.
Install LSPV load-sensing spring. Load weight into rear of vehicle until measured distance is 6 55/64" (174 mm) with lever slightly pressed in. See Fig 1. Slowly depress brake pedal. Check readings on pressure gauges. See LSPV PRESSURE SPECIFICATIONS table.
If fluid pressure is not within specification, ensure all other brake system components are okay. If other components are okay, replace LSPV assembly.

LSPV PRESSURE SPECIFICATIONS

Application

Inlet Pressure psi (kg/cm² )

Outlet Pressure psi (kg/cm² )

Pickup & Van/Wagon

Load-Sensing Spring

Removed

853 (60)

242-327 (17-23)

Installed

1991 (140)

⁽¹⁾ 299-583 (21-40)

Eclipse 2WD

1166 (82)

732-804 (52-57)

Eclipse 4WD

1166 (82)

789-860 (56-61)

⁽¹⁾	On vehicles with 2WD and heavy duty suspension, outlet pressure is 526-697 psi (37-49 kg/cm² ).

Fig 1: Testing LSPV (Pickup & Van/Wagon)

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

Fig 2: Connecting Pressure Gauges to LSPV

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.