Someone please explain the brake proportioning valve
 

I have a proportioning valve mounted on the right side firewall. My brakes are ok, but they dont stop the car like I think they should. The car hasa rear disc conversion, and I know the car used to be raced on a road course, it has also been to a driving school by one of the previous owners. So I am assuming it was used to set the brakes for a particular track. If I increase the pressure on the valve, will this give me more braking power? Or am I moving brake pressure from front to rear or vise versa? I dont really understand how they work other than they control pressure so the car will not skid under hard braking. Can anyone elaborate on this for me?

RE: Someone please explain the brake proportioning valve
 

Yes, That valve is used to adjust front and rear pressure. Your front brakes do the majority of the stopping due to the weight transfer when stopping. You can adjust to 50/50 or 60/40 ect...

RE: Someone please explain the brake proportioning valve
 

Is that style proportioning valve a stock item or is it an aftermarket add on?

RE: Someone please explain the brake proportioning valve
 

It's aftermarket, we didn't get abrake proportioning valve from the factory.

RE: Someone please explain the brake proportioning valve
 

Did your rear disc conversion come with a new master cylinder by chance? Because you need more pressure in the lines to use disc brakes. Your proportiong valve changes the balance of the pressure fore and aft when the front dips or if their is a load in the back or something. You probably need a new master cylinder with a bigger bore.

RE: Someone please explain the brake proportioning valve
 

Also if you dont have steel braded brake lines that will make a huuuuuuge difference! It will help with mushy pedal under hard braking and sensitivity of the brakes. A must if you track it at all!

RE: Someone please explain the brake proportioning valve
 

Sorry to say you are wrong, sir. Every car since like 1965 has em. On factory vehicles theyre self adjusting. The way it works is - lets say you nail the brakes hard, the front end dives, in order to keep the back brakes from locking up it reduces line pressure to the back wheels. Then lets say you load your car down to the point the ass is squatting. The proportioning valve will increase pressure to the rear to help slow the vehicle faster and more evenly.
-P.

RE: Someone please explain the brake proportioning valve
 

What he said. Stock cars are more front bias in braking. It is not because they want braking to suck. But it is because when you move braking bias torwards the rear, your rears can lock up (depends on just how much to what, ect ect ect). And that can cause your car to slide out. They basicly set the brakes up so you will always predictably slide forward. So when someone panic brakes. Also, another reason is because the stock suspension is soft, and the car pitches way forward when you brake. When you lower and stiffin the ride. Less weight is thrown forward. Thus you can put more brake bias torwards the rear.

RE: Someone please explain the brake proportioning valve
 

So, then I understand the front needs more pressure for braking perfomance. This is true in many applications, such as motorcycles where 80% of the stopping power is in the front rotors. I know I dont have braided lines, but why go to the trouble of installing a rear dics conversion, installing the valve, and not upgrading the lines? I am going to find out what rotors and pads I have on the back this weekend, they need some work. I guess I am just looking for a way to make sure I have all the available stopping power I need, and I am not familiar with the proportioning valve like it is set up.

RE: Someone please explain the brake proportioning valve
 

But with a bike, you get two levers. ONe for the front and one for the rear. Discs are always better. Less surface area being used in drum brakes, plus they get hot. Steel lines are a big plus. I have been wanting to get some. Along with some drilled & slotted rotors.