Brake Question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

gcburdic · 09-02-2008, 09:32 AM

Hey Guys and gals,

I plumbed in my hard lines and hooked up the power booster and master cylinder this weekend for my disc/drum setup, BUT in a schematic provided, I noticed they had a 10 lb residual valve plumb for the rear drum brakes???...
I think I know why they did this to prevent rear wheel lock up, but I wasn't sure if I needed to do this or is it in the prop valve??

Anyone done this???...if so, got any pics and where did you install this??
on the prop valve or closer to the rear axle??

Any help is much appreciated!

gcburdic · 09-02-2008, 01:19 PM

here's a link to what I am talking about....thanks

http://www.mbmbrakeboosters.com/Tech...gurations.html

I have my power booster and MC on the firewall....

68gmsee · 09-02-2008, 02:58 PM

When I first read your post, I thought it may be something I wasn't aware off. Now I know for sure, it's something I wasn't aware of.

From the read part you posted, it looks like it's a performance type product for quicker stops???

I have never heard of this before but that doesn't mean it's not being used in some of these trucks. However, I'm not sure I understand why you would need a 10lb residual pressure component to keep the break shoes close to the drums. On my rear breaks, I just adjust them until they are barely touching the drums. That's about as close as you can get them for stopping purposes.

umwtnt · 09-02-2008, 05:34 PM

You normally only use a residual valve when the master cylinder is lower the the brakes. Like when the master cylinder is mounted under the floor boards. In our application there is no need for one. A 10 lb is used for drum brakes and a 2 lb is used for disc brakes.

cparman · 09-02-2008, 08:17 PM

residual check valves are for brake systems where the master cylinder is LOWER than the brake calipers or the wheel cylinders. IF you master is in the stock location you should not need them.
www.mpbrakes.com
I like these guys, and go to their web site, and to their FAQ tech help area and it will talk about check valves

LONGHAIR · 09-02-2008, 08:47 PM

The residual valve is "built in" to the stock stuff. It is only necessary to "add" one in a "custom" application with a bunch of aftermarket "race" parts.
The point of the residual valve is to keep some pressure in the lines because of the springs that pull them back to the "resting" position.
Calipers don't have springs, they just "relax" when you let off of the pedal. Too much line pressure would cause them to drag against the rotors

gcburdic · 09-03-2008, 08:16 AM

Okay guys....Thanks alot for your responses.....I was worried I had to get that residual valve plumbed in too....I am so darn close to getting my project rolling I can't stand it!!!.....

Thanks again

09-02-2008, 09:32 AM	#1
gcburdic Restoration Virgin! Join Date: Jan 2008 Location: Huntersville, NC Posts: 8,298	Brake Question Hey Guys and gals, I plumbed in my hard lines and hooked up the power booster and master cylinder this weekend for my disc/drum setup, BUT in a schematic provided, I noticed they had a 10 lb residual valve plumb for the rear drum brakes???... I think I know why they did this to prevent rear wheel lock up, but I wasn't sure if I needed to do this or is it in the prop valve?? Anyone done this???...if so, got any pics and where did you install this?? on the prop valve or closer to the rear axle?? Any help is much appreciated! __________________ Geoff with a G 1968 Chevy C10 SWB The Mistress 1972 Custom Deluxe C20 Suburban A Suburban Named Isabella 1966 Ford Mustang Mama's High School Graduation Present

09-02-2008, 01:19 PM	#2
gcburdic Restoration Virgin! Join Date: Jan 2008 Location: Huntersville, NC Posts: 8,298	Re: Brake Question here's a link to what I am talking about....thanks http://www.mbmbrakeboosters.com/Tech...gurations.html I have my power booster and MC on the firewall.... __________________ Geoff with a G 1968 Chevy C10 SWB The Mistress 1972 Custom Deluxe C20 Suburban A Suburban Named Isabella 1966 Ford Mustang Mama's High School Graduation Present Last edited by gcburdic; 09-02-2008 at 01:21 PM.

09-02-2008, 02:58 PM	#3
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: Brake Question When I first read your post, I thought it may be something I wasn't aware off. Now I know for sure, it's something I wasn't aware of. From the read part you posted, it looks like it's a performance type product for quicker stops??? I have never heard of this before but that doesn't mean it's not being used in some of these trucks. However, I'm not sure I understand why you would need a 10lb residual pressure component to keep the break shoes close to the drums. On my rear breaks, I just adjust them until they are barely touching the drums. That's about as close as you can get them for stopping purposes.

09-02-2008, 05:34 PM	#4
umwtnt Registered User Join Date: Feb 2008 Location: Williamsburg, Va Posts: 226	Re: Brake Question You normally only use a residual valve when the master cylinder is lower the the brakes. Like when the master cylinder is mounted under the floor boards. In our application there is no need for one. A 10 lb is used for drum brakes and a 2 lb is used for disc brakes. __________________ The more I learn, the more I find out I don't know. 69 Chevy SWB w/67 front end 4 wheel discs 468 BB 700R4 Bagged Coming around slowly

09-02-2008, 08:17 PM	#5
cparman sharp as a marble Join Date: Jan 2007 Location: atlantic beach,florida Posts: 1,082	Re: Brake Question residual check valves are for brake systems where the master cylinder is LOWER than the brake calipers or the wheel cylinders. IF you master is in the stock location you should not need them. www.mpbrakes.com I like these guys, and go to their web site, and to their FAQ tech help area and it will talk about check valves

09-02-2008, 08:47 PM	#6
LONGHAIR just can't cover up my redneck Join Date: May 2004 Location: Columbus OH Posts: 11,414	Re: Brake Question The residual valve is "built in" to the stock stuff. It is only necessary to "add" one in a "custom" application with a bunch of aftermarket "race" parts. The point of the residual valve is to keep some pressure in the lines because of the springs that pull them back to the "resting" position. Calipers don't have springs, they just "relax" when you let off of the pedal. Too much line pressure would cause them to drag against the rotors

09-03-2008, 08:16 AM	#7
gcburdic Restoration Virgin! Join Date: Jan 2008 Location: Huntersville, NC Posts: 8,298	Re: Brake Question Okay guys....Thanks alot for your responses.....I was worried I had to get that residual valve plumbed in too....I am so darn close to getting my project rolling I can't stand it!!!..... Thanks again __________________ Geoff with a G 1968 Chevy C10 SWB The Mistress 1972 Custom Deluxe C20 Suburban A Suburban Named Isabella 1966 Ford Mustang Mama's High School Graduation Present



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