Hyundai Coupes/Sedans 1986-1993 Repair Guide

Proportioning Valve


The valve performs one or more of the following functions:

  1. Controls the amount of hydraulic pressure to the rear brakes.
  3. Warns of failure in the brake system (warning light on dash).
  5. Inactivates rear pressure control in case of failure in the front service brake system.

On Excels with manual transmissions produced up to December of 1987 and on Excels with automatic transmissions produced up to February of 1987, a Sumitomo type proportioning valve is used. From January 1988 for manual transmissions and March 1987 for automatic transmissions, a Kelsey-Hayes type proportioning valve is used on Excel. All Sonatas with rear drum brakes use the Kelsey-Hayes type proportioning valve.


Except Sonata With Rear Disc Brakes

See Figures 1 and 2

Click image to see an enlarged view

Fig. Fig. 1: Kelsey-Hayes type proportioning valve-1988-93 Excel, Elantra, Scoupe and Sonata with rear drum brakes

Click image to see an enlarged view

Fig. Fig. 2: Sumitomo type proportioning valve-1986-87 Excel

  1. Disconnect the negative battery cable. Disconnect the brake lines at the valve.

Use a flare nut wrench to avoid damage to the lines and fittings.

  1. Remove the mounting bolts and remove the valve.

If the proportioning valve is found to be defective, it must be replaced.

  1. Install the proportioning valve and tighten the mounting bolts to 15 ft. lbs. (20 Nm).
  3. Refill the system with fluid and bleed the brakes. Connect the negative battery cable.

Sonata With Rear Disc Brakes

See Figure 3

Click image to see an enlarged view

Fig. Fig. 3: Proportioning valve removal-Sonata with rear disc brakes

These models use a Bendix master cylinder as opposed to the Mando master cylinder used on rear drum brake vehicles. On the Bendix master cylinder, the proportioning valves are screwed directly in the master cylinder.

  1. Unplug the fluid level sensor wire from the bottom of the fluid reservoir.
  3. Using a line nut wrench, disconnect the fluid tubes from the proportioning valves. Plug the tube ends to prevent the loss of fluid.
  5. Unscrew the valves from the master cylinder body.
  7. Remove the valve 0-rings. Discard them and install new ones. Before installation, lubricate the new 0-rings with clean brake fluid.
  9. Screw the valves into the master cylinder and torque them to 10-16 ft. lbs. DO NOT overtighten or the 0-rings may be damaged.
  11. Connect and tighten the fluid tubes to the valves.
  13. Plug the fluid level sensor wire into the bottom of the fluid reservoir.
  15. Fill the fluid reservoir to the proper level and bleed the brakes.