Why are the rear brakes imbalanced across an axle axle?

If the hand brake is fine with little or no imbalance, that suggests all is well with the drums and brake shoes and no contamination. The brake compensator limits the pressure that can go to both wheels when the chassis is unladen so unlikely to cause an imbalance. Likely culprit is a seized wheel cylinder, but thats just a logical guess:)

Why is there bias in the brake proportioning valve?

However, one critical factor in establishing bias – the mechanical brake pressure proportioning valve – was left out of the discussion. After all, one can only take so much of this brake bias talk in one sitting. That said, we are back to share the intricacies of just how brake pressure is distributed to the front and rear of the vehicle.

What happens when the brake line pressure is too low?

It also determines the clamping force of the calipers. If the line pressure is too low, which is an all-too-common occurance, clamping force is reduced (much the same as putting a block under the brake pedal of your street car). The obvious consequence of this reduced clamping force is not being able to slow the car down quickly.

How does rear brake pressure affect front brake pressure?

However, once a preset pressure point is reached (600 psi in the example), the rear brake pressure continues to build, but at a slower rate (or slope) than the front brake pressure. Figure C displays this for us quite clearly.

What causes low air pressure in the brake system?

-Low air pressure in the brake system (below 60 psi). -Brake valve delivery pressure below normal. -Wrong size actuators and/or slack adjusters. -Failure of part of a dual air system. -If remote mounted brake valve, check linkage. 2.) Brakes Apply Too Slowly -Brakes need adjusting or lubricating.

Where does the low brake pedal come from?

In the next 5 minutes, you will have identified whether the issue causing your low pedal is in the front of your brake system or rear. Nearly every vehicle has a rubber hose at the center of the rear axle that attaches to a block on the rear end.

Why do you need a proportioning valve in your brake system?

You benefit by having a brake proportioning valve in your brake system because it helps you control brake balance. Your rear brakes may receive too much pressure during rapid deceleration if the proportioning valve is not functional. A properly-working proportioning valve ensures your rear brakes do not lock-up during heavy braking.

Why do you need a brake balance valve?

This valve is necessary for optimizing front-to-rear bias, also referred to as brake balance. It is a spring-loaded component that activates when fluid pressure builds when you step on the brake pedal. Then, the valve’s plunger unseats and fluid rushes into the calibrated range.