Re: Brake Proportioning Valve & Metering Valve ???
[Re: TJP]
#3156813
07/04/23 09:36 AM
07/04/23 09:36 AM
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Joined: Jan 2008
Posts: 1,212 Minn
SportF
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pro stock
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1st thing to establish is whether it is a proportioning valve or PRESSURE DIFFERENTIAL valve. The PD valve does nothing more than turn on the brake warning light if there should be a loss of pressure to 1 side of the system. This is a common misconception that started many years back This is also the valve that cuts off the low pressure (leaking) side. This is the valve that gives you the dual safety factor. Without it, you don't have a dual system.
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Re: Brake Proportioning Valve & Metering Valve ???
[Re: SportF]
#3156853
07/04/23 12:27 PM
07/04/23 12:27 PM
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Joined: Dec 2014
Posts: 5,816 ohio
ruderunner
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master
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Actually the master is where the dual braking comes from. Lots of vehicles built without the differential valve. The differential valve usually activates a light and some cut off flow to the leaking side, but not all.
Angry white pureblood male
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Re: Brake Proportioning Valve & Metering Valve ???
[Re: ruderunner]
#3156892
07/04/23 02:30 PM
07/04/23 02:30 PM
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Joined: Jan 2008
Posts: 1,212 Minn
SportF
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Actually the master is where the dual braking comes from. Lots of vehicles built without the differential valve. The differential valve usually activates a light and some cut off flow to the leaking side, but not all. No, no that is not true. That is what almost everybody thinks, but its not true.,. Do this, you got no shuttle valve? Open a bleeder and the pedal will go to the floor. If you have dual system, why will it do that? Its because you have no dual system. Maybe you've already bleed the brakes....what happened....the pedal goes to the floor. Actually, even with a shuttle valve it will go to the floor. You got to stab the pedal, get the shuttle valve to shift, light comes on, and the low side is sealed, pedal stops.
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Re: Brake Proportioning Valve & Metering Valve ???
[Re: SportF]
#3156957
07/04/23 04:26 PM
07/04/23 04:26 PM
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Joined: Dec 2014
Posts: 5,816 ohio
ruderunner
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master
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Incorrect. The pedal will not just go to the floor. It takes up the slack in the master (the pistons butt together) then builds pressure in the non leaking side.
Longer travel? You betcha but it will build pressure in the sealed side and stop the car.
Got a single master? Crack a bleeder and tell us what happens.
Angry white pureblood male
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Re: Brake Proportioning Valve & Metering Valve ???
[Re: SportF]
#3157455
07/06/23 10:03 AM
07/06/23 10:03 AM
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Joined: Jun 2014
Posts: 1,325 VA
dragon slayer
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If the distribution block sealed the low side to stop the leak, how would you bleed brakes? The Master training goes through this dual MC pretty well, the pistons do have tail piece to allow for direct contact to keep front and rear isolated in the case of a bad leak.
Last edited by dragon slayer; 07/06/23 10:05 AM.
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Re: Brake Proportioning Valve & Metering Valve ???
[Re: SportF]
#3157460
07/06/23 10:14 AM
07/06/23 10:14 AM
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Joined: Dec 2014
Posts: 5,816 ohio
ruderunner
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master
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ohio
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1967
1sr engineer: Hey look, I designed a brake valve block so that when a lower pressure or leak occurs, this piston slides over and lights a light!
2d engineer: Hey good. But, when the piston slides over, why don't you have it cut off the port to the leaking side. That way you'd have a safety factor.
1st: I can't do that.
2d: Why not?
1st: Because 50+ years in the future, a guy on the internet is going to say that isn't how its supposed to work.
2d: What is the internet?
1st: I don't know, but I think in the future, those folks will be smarter than us.
You've never studied how a dual master works have you?
Angry white pureblood male
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Re: Brake Proportioning Valve & Metering Valve ???
[Re: dragon slayer]
#3157461
07/06/23 10:15 AM
07/06/23 10:15 AM
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Joined: Dec 2014
Posts: 5,816 ohio
ruderunner
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master
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If the distribution block sealed the low side to stop the leak, how would you bleed brakes? The Master training goes through this dual MC pretty well, the pistons do have tail piece to allow for direct contact to keep front and rear isolated in the case of a bad leak. This.
Angry white pureblood male
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Re: Brake Proportioning Valve & Metering Valve ???
[Re: SportF]
#3157506
07/06/23 12:19 PM
07/06/23 12:19 PM
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Joined: Dec 2014
Posts: 5,816 ohio
ruderunner
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master
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It takes a sharp pressure spike to set it over. Just take a look at your valve block, look at the front lines. You can SEE that the piston will cut off the ports just the way the lines are on there.
But, I give up, you guys have dual brakes no matter what. One question, when you bleed your brakes, did the pedal go to the floor? I'm outta here. No, it doesn't go to the floor, it takes up the slack I the master, the pistons butt together then the master builds pressure in the other half. Ever bench bled a dual master? You can see it happening. Think about this, if your magic valve is so great, why wasn't it ever used with a single master? What happens if the line from your single master to your magic valve fails? I guess the millions upon millions of vehicles sold that don't have the valve are all in violation of federal law? Better get a lawyer and make it rich!
Angry white pureblood male
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Re: Brake Proportioning Valve & Metering Valve ???
[Re: dragon slayer]
#3158018
07/08/23 01:01 PM
07/08/23 01:01 PM
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Joined: May 2019
Posts: 6,250 nowhere
Sniper
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master
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This is the definitive training answer to explain it. From the 67 Master training. Unfortunately, the slide show link doesn't work, but watch the film movie. MC covered first, distribution block around 11m 27 sec. It clearly shows how the port does not close. The barbell shaped warning light trigger does not move far enough to close the outlet ports because of the warning light stud stops it. https://www.web.imperialclub.info/Repair/Lit/Films/232/ Stuff changes. From the 73 FSM, when talking about pressure bleeding the brakes it states the following.
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Re: Brake Proportioning Valve & Metering Valve ???
[Re: Sniper]
#3158887
07/11/23 05:11 PM
07/11/23 05:11 PM
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Joined: Jan 2008
Posts: 1,212 Minn
SportF
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pro stock
Joined: Jan 2008
Posts: 1,212
Minn
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This is the definitive training answer to explain it. From the 67 Master training. Unfortunately, the slide show link doesn't work, but watch the film movie. MC covered first, distribution block around 11m 27 sec. It clearly shows how the port does not close. The barbell shaped warning light trigger does not move far enough to close the outlet ports because of the warning light stud stops it. https://www.web.imperialclub.info/Repair/Lit/Films/232/ Stuff changes. From the 73 FSM, when talking about pressure bleeding the brakes it states the following. You mean the tech manual says the valve closes off flow? Gee, it must be wrong, eh?
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