proportion valve
6th Gear Member
Joined: May 2005
Posts: 5,736
From: MD/WV
RE: proportion valve
ORIGINAL: Soaring
I just now realized that we have some guys in high school on here who may be looking for a more simpler explanation about the physics of the front disk and rear drum brakes and what the proportioning valve really does.
The proportioning valve reduces the pressure to the rear brakes. Regardless of what type of brakes a car has, the rear brakes require less force than the front brakes.
The amount of brake force that can be applied to a wheel without locking it depends on the amount of weight on the wheel. More weight means more brake force can be applied. If you have ever slammed on your brakes, you know that an abrupt stop makes your car lean forward. The front gets lower and the back gets higher. This is because a lot of weight is transferred to the front of the car when you stop. Also, most cars have more weight over the front wheels to start with because that is where the engine is located.
If equal braking force were applied at all four wheels during a stop, the rear wheels would lock up before the front wheels. The proportioning valve only lets a certain portion of the pressure through to the rear wheels so that the front wheels apply more braking force. If the proportioning valve were set to 70 percent and the brake pressure were 1,000 pounds per square inch (psi) for the front brakes, the rear brakes would get 700 psi.
I just now realized that we have some guys in high school on here who may be looking for a more simpler explanation about the physics of the front disk and rear drum brakes and what the proportioning valve really does.
The proportioning valve reduces the pressure to the rear brakes. Regardless of what type of brakes a car has, the rear brakes require less force than the front brakes.
The amount of brake force that can be applied to a wheel without locking it depends on the amount of weight on the wheel. More weight means more brake force can be applied. If you have ever slammed on your brakes, you know that an abrupt stop makes your car lean forward. The front gets lower and the back gets higher. This is because a lot of weight is transferred to the front of the car when you stop. Also, most cars have more weight over the front wheels to start with because that is where the engine is located.
If equal braking force were applied at all four wheels during a stop, the rear wheels would lock up before the front wheels. The proportioning valve only lets a certain portion of the pressure through to the rear wheels so that the front wheels apply more braking force. If the proportioning valve were set to 70 percent and the brake pressure were 1,000 pounds per square inch (psi) for the front brakes, the rear brakes would get 700 psi.
4th Gear Member
Joined: Sep 2006
Posts: 1,188
From: 1984
RE: proportion valve
I have a '66 with front discs, and I 'm getting ready to switch over to a dual MC with a factory style combo valve. The only source I've found for a new combo valve is NPD, cost$120. This valve eliminates any need for adjustment.
I ♥ Acer
Joined: Oct 2004
Posts: 17,565
From:
RE: proportion valve
ORIGINAL: baddog671
No need for insults now...
ORIGINAL: Soaring
I just now realized that we have some guys in high school on here who may be looking for a more simpler explanation about the physics of the front disk and rear drum brakes and what the proportioning valve really does.
The proportioning valve reduces the pressure to the rear brakes. Regardless of what type of brakes a car has, the rear brakes require less force than the front brakes.
The amount of brake force that can be applied to a wheel without locking it depends on the amount of weight on the wheel. More weight means more brake force can be applied. If you have ever slammed on your brakes, you know that an abrupt stop makes your car lean forward. The front gets lower and the back gets higher. This is because a lot of weight is transferred to the front of the car when you stop. Also, most cars have more weight over the front wheels to start with because that is where the engine is located.
If equal braking force were applied at all four wheels during a stop, the rear wheels would lock up before the front wheels. The proportioning valve only lets a certain portion of the pressure through to the rear wheels so that the front wheels apply more braking force. If the proportioning valve were set to 70 percent and the brake pressure were 1,000 pounds per square inch (psi) for the front brakes, the rear brakes would get 700 psi.
I just now realized that we have some guys in high school on here who may be looking for a more simpler explanation about the physics of the front disk and rear drum brakes and what the proportioning valve really does.
The proportioning valve reduces the pressure to the rear brakes. Regardless of what type of brakes a car has, the rear brakes require less force than the front brakes.
The amount of brake force that can be applied to a wheel without locking it depends on the amount of weight on the wheel. More weight means more brake force can be applied. If you have ever slammed on your brakes, you know that an abrupt stop makes your car lean forward. The front gets lower and the back gets higher. This is because a lot of weight is transferred to the front of the car when you stop. Also, most cars have more weight over the front wheels to start with because that is where the engine is located.
If equal braking force were applied at all four wheels during a stop, the rear wheels would lock up before the front wheels. The proportioning valve only lets a certain portion of the pressure through to the rear wheels so that the front wheels apply more braking force. If the proportioning valve were set to 70 percent and the brake pressure were 1,000 pounds per square inch (psi) for the front brakes, the rear brakes would get 700 psi.
I ♥ Acer
Joined: Oct 2004
Posts: 17,565
From:
RE: proportion valve
ORIGINAL: baddog671
I am 19 but I have a legit reason for asking u so many questions. I dont have anything to inspect and see how it works. I just have the MC and the brakes.
I am 19 but I have a legit reason for asking u so many questions. I dont have anything to inspect and see how it works. I just have the MC and the brakes.
5th Gear Member
Joined: Mar 2006
Posts: 2,328
From: Where I lay my head is home
RE: proportion valve
ORIGINAL: Soaring
It's a shame the government/state schools took out auto mechanics from our high schools. I am sorry you are among the many thousands of young men who were not given the opportunity to be exposed to a hands on high school auto mechanics course where you leaned how to do much of what we have been discussing on here.
ORIGINAL: baddog671
I am 19 but I have a legit reason for asking u so many questions. I dont have anything to inspect and see how it works. I just have the MC and the brakes.
I am 19 but I have a legit reason for asking u so many questions. I dont have anything to inspect and see how it works. I just have the MC and the brakes.
BWAHAHAHAHAHAHA!!!!!!
I was in Vo-Tec for about a month and a half before deciding I would rather take a normal class instead. I learned more about lawn mower motors than real motors and all I had to work on was a Saturn motor and all that was asked of me was to r&r the plugs and put the wires back on in order.
They didn't even show me how to change the oil! I learned more form trial and error in my own car than vo-tec or working in Pep Boys.
Best lesson: If your rotor bearings fall in the dirt, clean out all the grease and make sure there is no grains of sand left in the bearings before trying to re-install them. They WILL lock up and they will get stuck on the spindles.
That was a mess!
5th Gear Member
Joined: Mar 2006
Posts: 2,328
From: Where I lay my head is home
RE: proportion valve
The prop valve can go anywhere ON THE REAR LINE between the MC and rear where the line splits out to the two drums. Easiest spot to put it would be near the firewall/MC.
Thread Starter
5th Gear Member
Joined: Jun 2005
Posts: 2,258
From: So. California
RE: proportion valve
[blockquote]
ORIGINAL: Soaring
No, you don't just put it anywhere. You connect it to the front bowl of the dual MC and run it to the back brakes.
No, you don't just put it anywhere. You connect it to the front bowl of the dual MC and run it to the back brakes.
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