Brake Proportioning Valve – Why is it important to Helper Springs?

Brake Proportioning Valve – Why is it important to Helper Springs

Proportioning Valve Linkage

Before the introduction of ABS brakes, most vehicles on the road had brake proportioning valves.   A brake proportioning valve controls the front to rear bias of the brake system to avoid locking up the rear wheels during a rapid stop.   Most of the brake proportioning valves installed are fixed in their bias and do not change the bias as the vehicle is loaded.   Some pickup trucks, mostly Toyota and Dodge, use a load sensing brake proportioning valve to vary front to rear bias as load is added to the vehicle.   This type of proportioning valve is mounted on the frame rail and connected to the axle by a linkage so that the valve can detect when a load has been added to the vehicle.    This type of valve can be affected by the addition of helper springs as there will not be as much spring deflection when the helper springs are used on the vehicle.   Because the vehicle springs deflect less when helper springs are installed, the adjustable brake proportioning valve may not deliver as much braking force to the rear wheels and it could increase stopping distances.   If your vehicle is equipped with an adjustable brake proportioning valve it is important that the linkage to the adjustable brake proportioning valve be adjusted when helper springs are added to the vehicle.  If you do not feel confident making this adjustment yourself, bring the vehicle to a professional for proper adjustment of the linkage.


David Wheeler

Hellwig Products Inc.

559-734-7451   Phone

559-734-7460   Fax





Posted on Thursday, June 27th, 2013 in Tech Story.
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