Typical Brake System Configurations
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Figuring out how to plumb your brake system is quite simple. The two qualifying questions are:

1)  Is your brake system: Disc/Disc, Disc/Drum, or Drum/Drum?  Because...

  • Drum brakes require a 10 lb. residual pressure (RPV10) to counteract the spring tension in the drum system which tends to pull the shoes away from the drums.
  • Disc Brakes require a combination valve (often called a proportioning valve) and sometimes a 2 lb. residual valve- depending on where your master cylinder is relative to your calipers (see next bullet).

2)  For disc applications; Is your Master Cylinder mounted above or below your calipers? because...

  • If your master cylinder is below your calipers then a 2 lb. residual valve (RPV2) is needed to prevent fluid from flowing back from the calipers into the master cylinder.

Quick Reference Sheet:

DRUM BRAKES FRONT AND REAR WITH MASTER ON FIREWALL OR UNDER FLOOR
  • drum/drum, firewall or under floor

Drum brakes require a 10 lb. residual pressure (RPV10) to counteract the spring tension in the drum system which tends to pull the shoes away from the drums. This will give you a longer pedal travel and "spongy" brakes. The residual valve holds a pressure keeping the shoes near the drums giving a higher firmer pedal. Also required a metering valve (PVM) to the front (the metering valve prevents nose dive).

DISC BRAKES FRONT AND DRUMS REAR WITH MASTER ON FIREWALL
  • disc/drum, firewall

A disc/drum combination valve (PV2) is the easiest way to properly balance your braking system. The combination valve is two valves in one. It provides metering to the front which prevents nose dive and proportioning to the rear which prevents rear wheel lock up. We also recommend the addition of a 10 lb residual valve (RPV10) to the rear drum brakes.

DISC BRAKES FRONT AND DRUMS REAR WITH MASTER UNDER FLOOR
  • disc/drum, under floor

The best way to plumb a disc/drum system when the master is under the floor is with a combination valve (PV2) and then a 2 pound residual valve (RPV2) to the front which is needed to prevent fluid from flowing back from the calipers into the master. We also recommend the addition of a 10 lb residual valve (RPV10) to the rear drum brakes.

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DISC BRAKES FRONT AND DISCS REAR WITH MASTER ON FIREWALL
  • disc/disc, fire wall

The best way to plumb a disc/disc system when the master is on the firewall is with a four wheel disc brake combination valve (PV4).

DISC BRAKES FRONT AND DISCS REAR WITH MASTER UNDER FLOOR
  • disc/disc, under floor

The best way to plumb a disc/disc system when the master is under the firewall is with a four wheel disc brake combination valve (PV4) and a two pound residual valve (RPV2) to the front and a two pound residual valve (RPV2) to the rear.
 


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