Mazda MX-3 silhouetteMX-3

Dual Proportioning Valve - Inspection, Replacement

P-30parts diagram

Fluid pressure differs for ABS, K8 DOHC (non ABS), and B6 DOHC (non ABS). Replacement diagram shows separate NON ABS MODEL and ABS MODEL valves.

Inspection

Dual Proportioning Valve Inspection

  1. 1
    Connect the SSTs to the brake pipes with adapters as shown in the figure.
    Connect the brake pipes with SST (49 0259 770B)
    Illustration of the SST gauges connected to the brake pipes with adapters for the dual proportioning valve inspection. Tool labels: 49 U043 004, 49 U043 006, 49 U043 005.
  2. 2
    Bleed the air from the brake system. (Refer to page P-7.)
  3. 3
    Depress the brake pedal until the master cylinder pressure equals A; then record rear brake pressure A'.
    Graph plotting rear brake pressure (vertical axis) against master cylinder pressure (horizontal axis) showing a bilinear proportioning curve with breakpoints A/A' and B/B' marked by dashed lines.
  4. 4
    Depress the brake pedal again, apply additional pressure until the pressure equals B; then record pressure B'.
Adapter and flare nut
126 - 211N·m

Fluid pressure kPa {kgf/cm2, psi}

ABS
A2,453 {25,356}
A'2,453 {25,356} ±196 {2,28}
B5,886 {60,853}
B'3,826 {39,555} ±333 {3,43}
K8 DOHC (non ABS)
A2,453 {25,356}
A'2,453 {25,356} ±196 {2,28}
B5,886 {60,853}
B'3,138 {32,455} ±294 {3,43}
B6 DOHC (non ABS)
A2,943 {30,427}
A'2,943 {30,427} ±196 {2,28}
B5,886 {60,853}
B'3826 {39,555} ±284 {3,43}

Replacement

Dual Proportioning Valve Replacement

  1. 1
    Remove in the order shown in the figure, referring to Removal Note.
    Exploded view of the dual proportioning valve replacement showing NON ABS MODEL (left) and ABS MODEL (right). Numbered balloon callouts: 1 brake pipe (SST), 2 bolt, 3 dual proportioning valve. Labels FROM HYDRAULIC UNIT, TO REAR BRAKE, R MARK. Torque values: 12.8—21.5 N·m {130—220 kgf·cm, 113—190 in·lbf} and 19—22 {1.9—2.3, 14—16}.
  2. 2
    Install in the reverse order of removal, referring to Installation Note.
  3. 3
    After installation, add brake fluid, bleed air, and check for fluid leakage.
Parts DiagramFig. fig3
#Part NameNotes
1Brake pipeRemoval / Installation Note page P-31
2Bolt
3Dual proportioning valveInstallation Note page P-31
Tightening torque (brake pipe, SST)
126 - 211N·m
Tightening torque (bolt, item 2)
186 - 216N·m

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