Do I need a brake proportion valve? Whats it for?

For the rear of my taco Im getting it lifted 2" with toytec aal's. Do I need a brake proportioning valve bracket? I have looked at the 2.5 inch toytec spacer lift and it included that brake proportioning valve thing.(not going with spacer lift) just wanted to know do I need that brake proportioning valve bracket? Dont want to get something I dont even need cause it will be wasting money.
(Im getting 5100's and eibach springs and 2" aal in the rear.)

 

It helps even the brake load for front and rear, with the loft in the back, they front brakes are going to be getting used more than the rear without the bracket. I'd look at Beefed Tacos BPV bracket, it's made of better material, and it's about the same price as the flimsy Toytec one.

 

thanks

 

But why...?
I get it, that without the bracket a lifted truck with shift more braking to the front than stock. But what is the functional reasoning? If the truck were stock and the bed were unloaded the braking would be balanced, but why proportion the braking to the load in the bed? when loaded the distance from the frame to the rear axle housing is shorter activation the proportioning valve. So in stock situation and there was a heavy load in the bed, it would seem that the truck would proportion braking away from the front and move it to the rear.
Whats the advantage to this as the front brakes seem stronger?

 

The rear proportioning valve in my opinion is a bit of over engineering, useful but not needed. However your Tacoma was designed to use it so you should retain it and ensure that it is working properly.

 

the brakes are usually divide between 60-70% fronts and the rest to the rear,(in general) Helps you STOP as apposed to sliding. Also the load in the bed has to be calulated to get the best (shortest) stopping distance.
Jump on a mountain bike and slam on the rear brake while on asphalt.. you slide. now lock up the front... it Stops. the proportioning valve makes it all work together.

 

So I might be slow on this, but when the bed/frame is lower to the axle as when weighted, why does it take stopping power from the front brakes?

I did the bracket install, but am just curious as to why it was engineered this way.

 

I'll try to explain this ....so please pardon.

Toyota put a mechanical sensing device under the truck bed to sense the load - so the brakes could adjust accordingly for optimum braking performance when you are carrying a heavy load.

If you look underneath the truck, its a long steal (round bar) that goes from the axle to the bed (where the sensor is).

You LIFT the rear of the truck, this changes the input at the sensor assuming you have a *LIGHTER THAN STOCK* load in the bed.

The Brake proportioning bracket - should be the same height as your lift. This puts the sensor back to ORIGINAL position of the STOCK LOAD. So, if & when you ever put a load in the truck, the sensor can act as it would normally and give you the braking performance that Toyota engineered.

2nd gen trucks don't have one...so I'm not sure how that works....

 

Couldn't of said it better myself


a lot of guys with auto trans will burn up the brakes faster ( manual trans is a little less because of engine braking) after installing a lift because the rears are not being used as they should. I ran with out a relocate bracket for the longest time after installing mine the stopping power way noticeably better. You can always make one for a few bucks it doesn't take much.

I also offer 2 different sizes my design is fully adjustable so if you lift higher or don't like the stopping power you can always move it up.
http://www.tacomaworld.com/forum/bay-area-metal-fabrication/184065-b-m-f-bpv-relocate-bracket.html

 

It helps even the brake load for front and rear.

 

Truth. Warped my front brake rotors after my lift.

 

So a weighted bed increases the brake proportioning towards the rear brakes. Ok, it still seams counter intuitive as the front brakes have more stopping power. Or does the truck really stop better with more rear brakes with the bed loaded?

 

When the bed is lightest, the rear brake doesn't have as much effect on stopping power. As you add weight, the rear brake has more effect. The total stopping power is improved when you use both front and rear brakes.

 

the front brakes have more stopping power because when you stop all the weight is shifted forward to the front wheels, and they won't skid as easy as the rears. The back wheels will lock up when they have no weight on them. When you load up the bed, you have weight on them now, so you can give the brakes
"more" power to stop the truck better without skidding the rear wheels.

 

Anytime you add weight - you need more stopping power. Ask anyone who tows....more weight = more momentum = longer stopping distance. The front brakes will always have more stopping power. It's the rear brakes that will get MORE and be more effective.

Aside from all that - there's a weight distribution thing that also plays a role in the engineering of the braking. Put a lot of weight in the bed and the front end of the truck will pitch upward. This 'decreases' steering effectiveness and can also decrease braking effectiveness simply because the weight isn't there. So again, the brake proportioning is designed / engineered for optimum braking performance based on all those factors that have already been listed.

 

Now makes perfect sense !

Thank you all !

 

Bump for Jerry's OUTSTANDING workmanship. His BPV brackets are VERY well engineered and permit quick/convenient adjustment.

 

Bringing up an older post here...

So I installed Jerry's bracket, and I am looking into doing my rear brakes, but, how do I know my BPV is actually functioning the way it should?

I have done a few other mods to my truck, things that take WAY more time then they should because of rust and corrosion on a truck that has been in Chicago the entire time I have owned it.

Am I over-assuming that my BPV would be affected in the same way that most other under carriage parts are on my truck?

 

A proportioning valve is used whenever a vehicle has disc brakes front and drum brakes rear. Disc brakes require "static pressure" to keep the pads close to the rotors, and the drums use wheel cylinders and shoes. The valve makes it possible for two brake types to work together. If you were to use 4 wheel disc brakes you wouldn't need the proportioning valve.

 

Bumping this 8 year old thread to help others understand about this device. Janster explains the importance of it exceptionally well. (Read quoted info above.)