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Discussion Starter · #1 ·
My setup has 3 out going lines as the way I see t theres an extra part I dont know what its called attached to the booster and the new ones Im looking at have only 2 lines.
So does that mean I will need to keep the extra part? Or is there a way to attach it to the new master cylinder? Its the part on the bottom right of the pic Maybe I should just get a new MC
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Discussion Starter · #3 ·
Looks like either a proportioning valve or a distribution block. I'm not familiar with the earlier cars so I'm not sure which, or if this is stock. The master cylinder only has 2 brake lines coming from it. You need one to each side on the front. That part is how it's currently done on your car.
So my reason for this is Im having to replace the brake booster, its right on top of my valve cover and the rockers are tapping so I need taller vc, so Im thinking of replacing all the booster master cylinder etc, theres 3 lines going out can you tell me the new ones is there enough exit ports on the master & proportioning valve for 3 lines? To your knowledge
 

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So my reason for this is Im having to replace the brake booster, its right on top of my valve cover and the rockers are tapping so I need taller vc, so Im thinking of replacing all the booster master cylinder etc, theres 3 lines going out can you tell me the new ones is there enough exit ports on the master & proportioning valve for 3 lines? To your knowledge
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My setup has 3 out going lines as the way I see t theres an extra part I dont know what its called attached to the booster and the new ones Im looking at have only 2 lines.
So does that mean I will need to keep the extra part? Or is there a way to attach it to the new master cylinder? Its the part on the bottom right of the pic Maybe I should just get a new MC View attachment 157393
Poportioning valve is below the master, that looks like a distribution block but better pictures would help on where the lines go. Mine is aftermarket and two lines come out of the master to the p valve then two lines out down to the dist block where it's split into three...one to each front wheel, one to the rears where on top of the diff another dist block splits they lines to each rear wheel.
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Discussion Starter · #9 ·
The distribution block on my '65 is down on the frame,
So you put it on the block and replumbed it up to the new proportioner? Smart,bit hard to get to I cant even get to my clutch arm to adjust the clutch the headers are in the way, I've tried several times took the spring off cant turn the bolt, another words its really crowded there and I dont have a lift.
I looked into adding a coupler pipe to pipe and replumb from there
 

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So you put it on the block and replumbed it up to the new proportioner? Smart,bit hard to get to I cant even get to my clutch arm to adjust the clutch the headers are in the way, I've tried several times took the spring off cant turn the bolt, another words its really crowded there and I dont have a lift.
I looked into adding a coupler pipe to pipe and replumb from there
It's stock I'm assuming on a '65, I didn't install it. It's just a splitter and yes it's very hard to get to even with manifolds. Why Pontiac put it there I don't know because it gets a lot of heat.
 

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So it's in place of a poportioning valve? Idk remember what brakes Droach has.
Nope. A simple junction block just diverts the brake fluid/pressure to your brake drums - like the single line from a single reservoir MC goes to the block, then you have an output hole for each front drum and one for the rear line which splits off at the rubber hose/fitting "T" on the rear axle. Drum brakes use the same pressure, so no metering valve, and the junction block.

The proportioning valve is used on a dual reservoir MC because it has to have 2 lines going into it, one for the front brakes and one for the rear brakes. The difference is that it has a "check valve" internally that is kept centered by equal brake fluid pressure (thus the need for a dual/2-line MC) when brakes are applied and the brake fluid goes out to the front/rear brakes. IF a leak develops in the rear brake system or the front brake system, there is an un-equal pressure now going through the proportioning valve - say your front rubber brake line blows out. When you hit your brakes, because the front line busted, the fluid pumps out the line and will not develop any pressure because it is like an open hole and fluid just passes out. However, when this happens, you apply the brakes and there is pressure developed going to the rear brakes because there is no leak in that system. The pressure developed in the rear brakes when you apply the brakes, sends that pressure through the proportioning valve and that pressure pushes that check valve in the proportioning valve forward to close off the front braking system BECAUSE there is no pressure being build up in the front brakes to keep that check valve centered.

So think of the proportioning valve, with its check valve, as a way to block off the flow of the brake fluid going to the brake system that develops a leak or breaks a line so you still have one brake system to stop the car rather than put the brake pedal to the floor and all the fluid is pushed out the bad line.

Additionally, the proportioning valve has an electrical pin above the check valve and if the check valve goes off center because a brake line ruptures, it grounds out on the proportioning valve body and the "Brake" warning light comes on on your dash to notify you there is a problem with the brake system and it needs to be checked out.

Could you adapt a proportioning valve to a single line MC? Probably, but your would need a junction block that had 3 openings, 1 for the MC going into it and then 1 line each to go into the top of the proportioning valve to act the same as the 2-lines that would normally come out of the dual reservoir MC.

The metering valve is used to balance the pressure differential between disc brakes and drum brakes as the size of the piston bores are different and not all even as compared to an all drum set-up. Otherwise, the discs would lock up or apply much harder and you could/would go into a skid with all the braking power going to the front tires.
 

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Nope. A simple junction block just diverts the brake fluid/pressure to your brake drums - like the single line from a single reservoir MC goes to the block, then you have an output hole for each front drum and one for the rear line which splits off at the rubber hose/fitting "T" on the rear axle. Drum brakes use the same pressure, so no metering valve, and the junction block.

The proportioning valve is used on a dual reservoir MC because it has to have 2 lines going into it, one for the front brakes and one for the rear brakes. The difference is that it has a "check valve" internally that is kept centered by equal brake fluid pressure (thus the need for a dual/2-line MC) when brakes are applied and the brake fluid goes out to the front/rear brakes. IF a leak develops in the rear brake system or the front brake system, there is an un-equal pressure now going through the proportioning valve - say your front rubber brake line blows out. When you hit your brakes, because the front line busted, the fluid pumps out the line and will not develop any pressure because it is like an open hole and fluid just passes out. However, when this happens, you apply the brakes and there is pressure developed going to the rear brakes because there is no leak in that system. The pressure developed in the rear brakes when you apply the brakes, sends that pressure through the proportioning valve and that pressure pushes that check valve in the proportioning valve forward to close off the front braking system BECAUSE there is no pressure being build up in the front brakes to keep that check valve centered.

So think of the proportioning valve, with its check valve, as a way to block off the flow of the brake fluid going to the brake system that develops a leak or breaks a line so you still have one brake system to stop the car rather than put the brake pedal to the floor and all the fluid is pushed out the bad line.

Additionally, the proportioning valve has an electrical pin above the check valve and if the check valve goes off center because a brake line ruptures, it grounds out on the proportioning valve body and the "Brake" warning light comes on on your dash to notify you there is a problem with the brake system and it needs to be checked out.

Could you adapt a proportioning valve to a single line MC? Probably, but your would need a junction block that had 3 openings, 1 for the MC going into it and then 1 line each to go into the top of the proportioning valve to act the same as the 2-lines that would normally come out of the dual reservoir MC.

The metering valve is used to balance the pressure differential between disc brakes and drum brakes as the size of the piston bores are different and not all even as compared to an all drum set-up. Otherwise, the discs would lock up or apply much harder and you could/would go into a skid with all the braking power going to the front tires.
Got it, it's strange because when I got my '65 it had a single reservoir with drums all around, no booster and didn't have that, just the block down on the frame.
 

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Discussion Starter · #16 ·
Well I just ordered a new Booster Mc proportioning valve 8" dual anything anyone can tell me is appreciated. Im really anxious to geter done and be able to drive my car without so many worries
My one question is the articles Ive read state a distance of 1/16" of the rod to the bore is there away of doing that before the install? I'll try to find it on Youtube
 

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Discussion Starter · #17 ·
Nope. A simple junction block just diverts the brake fluid/pressure to your brake drums - like the single line from a single reservoir MC goes to the block, then you have an output hole for each front drum and one for the rear line which splits off at the rubber hose/fitting "T" on the rear axle. Drum brakes use the same pressure, so no metering valve, and the junction block.

The proportioning valve is used on a dual reservoir MC because it has to have 2 lines going into it, one for the front brakes and one for the rear brakes. The difference is that it has a "check valve" internally that is kept centered by equal brake fluid pressure (thus the need for a dual/2-line MC) when brakes are applied and the brake fluid goes out to the front/rear brakes. IF a leak develops in the rear brake system or the front brake system, there is an un-equal pressure now going through the proportioning valve - say your front rubber brake line blows out. When you hit your brakes, because the front line busted, the fluid pumps out the line and will not develop any pressure because it is like an open hole and fluid just passes out. However, when this happens, you apply the brakes and there is pressure developed going to the rear brakes because there is no leak in that system. The pressure developed in the rear brakes when you apply the brakes, sends that pressure through the proportioning valve and that pressure pushes that check valve in the proportioning valve forward to close off the front braking system BECAUSE there is no pressure being build up in the front brakes to keep that check valve centered.

So think of the proportioning valve, with its check valve, as a way to block off the flow of the brake fluid going to the brake system that develops a leak or breaks a line so you still have one brake system to stop the car rather than put the brake pedal to the floor and all the fluid is pushed out the bad line.

Additionally, the proportioning valve has an electrical pin above the check valve and if the check valve goes off center because a brake line ruptures, it grounds out on the proportioning valve body and the "Brake" warning light comes on on your dash to notify you there is a problem with the brake system and it needs to be checked out.

Could you adapt a proportioning valve to a single line MC? Probably, but your would need a junction block that had 3 openings, 1 for the MC going into it and then 1 line each to go into the top of the proportioning valve to act the same as the 2-lines that would normally come out of the dual reservoir MC.

The metering valve is used to balance the pressure differential between disc brakes and drum brakes as the size of the piston bores are different and not all even as compared to an all drum set-up. Otherwise, the discs would lock up or apply much harder and you could/would go into a skid with all the braking power going to the front tires.
So I ordered all new booster master cvl and propr valve will I need to keep this metering valve with the new do you think. Its a 8" booster for discs front drums rear
 

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So I ordered all new booster master cvl and propr valve will I need to keep this metering valve with the new do you think. Its a 8" booster for discs front drums rear

Here is what I posted on brakes: "A Metering Valve is used to the front line going to the disc brakes (for both manual/power disc) and prevents application of the front disc brakes until about 75 PSI is built up in the system so that the rear brakes contact the drums at the same time - otherwise the front disc brakes will apply first or lock up causing erratic braking.

You can leave it off and try it and if the front disc brakes lock up and you go through the windshield, or put the car into an uncontrollable skid that totals out your car, then you will know you should have used it. (y)
 

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Discussion Starter · #19 ·
Here is what I posted on brakes: "A Metering Valve is used to the front line going to the disc brakes (for both manual/power disc) and prevents application of the front disc brakes until about 75 PSI is built up in the system so that the rear brakes contact the drums at the same time - otherwise the front disc brakes will apply first or lock up causing erratic braking.

You can leave it off and try it and if the front disc brakes lock up and you go through the windshield, or put the car into an uncontrollable skid that totals out your car, then you will know you should have used it. (y)
I was just reading this article prior to you sending this and it sounds as if I should leave it the setup goesout of the propor valve to the metering valve back into the front of the propr valve . So I guess the front of the prop valve is for the discs and the back ports are for my rear drums which go to the brake junction block out to the rear drums damn I thought it was just going to be remove all install new put in brake fluid bleed and done. WRONG! But I've learned an awful lot
Tanks again PJ
 
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