The Mitsubishi 1983-86 Pick-ups and the 1983-91 Monteros are equipped with a Blend Proportioning Valve (BPV). The BPV is located on the left rear frame near the rear axle for the 1983-86 Pick-ups. Not all 1983-86 Pick-ups are equipped with BPV's; some Pick-ups are equipped with a load sensing proportioning valve. The 1983-90 Monteros with the 2.6L engines also have the BPV mounted back by the rear axle. The 1989-91 Monteros with the 3.0L engines have it mounted just below the brake booster.
The BPV cannot be adjusted, however, if the vehicle is exhibiting strange or dangerous braking tendencies, have the BPV tested at a reputable automotive service center. If the BPV is faulty it will have to be replaced with a new unit.
REMOVAL & INSTALLATION
Disconnect the brake lines from the valve. Remove the mounting bolt(s) and remove the unit. Replace the proportioning valve with one having the same numerical code, only. Install the mounting bolt(s) and connect all four brake lines, tightening the flare nuts to 9-12 ft. lbs. (12-16 Nm). Bleed the system thoroughly.