Drum/drum brakes??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

65standard · 02-03-2015, 06:14 PM

Is my 1970 C20 manual drum/drum brakes supposed to have a proportioning valve? And if I add a power booster, do you use a proportioning valve?

**Stocker** · 02-03-2015, 06:51 PM

Nope. The prop. valve is to increase line pressure to front discs, as they require more than drums. Same with a power booster -- no prop. valve req'd with drum/drum setup.

65standard · 02-03-2015, 07:19 PM

Thanks for the info Mike

**FirstOwner69** · 02-03-2015, 07:47 PM

Quote:

Originally Posted by Stocker

Nope. The prop. valve is to increase line pressure to front discs, as they require more than drums. Same with a power booster -- no prop. valve req'd with drum/drum setup.

Correct. BUT, he does need a distribution block if for some reason he doesn't already have one.

65standard · 02-03-2015, 08:10 PM

I guess that is what was cut out of the brake system when the truck lived in the junkyard. Any clue as where I can get one of these? Look like a chevy dealer only part. Then again, I doubt a dealer would be able to get a 45 year old part.

**FirstOwner69** · 02-03-2015, 09:27 PM

Quote:

Originally Posted by 65standard

I guess that is what was cut out of the brake system when the truck lived in the junkyard. Any clue as where I can get one of these? Look like a chevy dealer only part. Then again, I doubt a dealer would be able to get a 45 year old part.

Check out the parts board for trucks being parted or buy new from Inline Tube
http://inlinetube.com/Prop%20Valves/PR-112.htm

Maybe this ad on the parts board... looks like he's not responding though.
http://67-72chevytrucks.com/vboard/s...d.php?t=658475

65standard · 02-03-2015, 09:47 PM

Thank you, I appreciate the links.

**FirstOwner69** · 02-03-2015, 10:14 PM

Quote:

Originally Posted by 65standard

Thank you, I appreciate the links.

It looks like you may also need the bracket that holds the distribution block as shown in my picture. However, it may be there and a bit bent. Hard to see in your pic.

**jocko** · 02-04-2015, 02:10 AM

LMC sells them. Over $200 last time I bought one though... Distro block also provides the signal for your dash brake light - indicates when one circuit has been lost - safety feature.

Don Quixote · 02-04-2015, 07:27 AM

www.classicparts.com has the distribution blocks for drum/drum for $80. They're out there and they're not expensive. I recently replaced mine.

**RodnRudy** · 02-04-2015, 08:47 PM

I've got a distribution block laying on the floor of my garage, took it off my running driving 68 C10 truck. Upgrading to disc brakes so I've got all new stuff. It's free to you if you PM me your address.
Phil

65standard · 02-04-2015, 09:01 PM

Thank you Phil, much appreciated. I'll PM you.

02-03-2015, 06:14 PM	#1
65standard Registered User Join Date: Dec 2014 Location: Coal City, IL Posts: 695	Drum/drum brakes??? Is my 1970 C20 manual drum/drum brakes supposed to have a proportioning valve? And if I add a power booster, do you use a proportioning valve? __________________ Tony Nicholas @ Midwest Metal Masters 1953 Chevy 3100 392 Hemi w/727 & 9” Ford 1985 Chevy C/10 6.0L 4L80 373 locker

02-03-2015, 06:51 PM	#2
Stocker 20' Daredevil (Ret) Join Date: May 2003 Location: Jefferson State Posts: 13,561	Re: Drum/drum brakes??? Nope. The prop. valve is to increase line pressure to front discs, as they require more than drums. Same with a power booster -- no prop. valve req'd with drum/drum setup. __________________ - Mike - 1972 K20 LWB 350/350/205 RIP El Jay

02-03-2015, 07:19 PM	#3
65standard Registered User Join Date: Dec 2014 Location: Coal City, IL Posts: 695	Re: Drum/drum brakes??? Thanks for the info Mike __________________ Tony Nicholas @ Midwest Metal Masters 1953 Chevy 3100 392 Hemi w/727 & 9” Ford 1985 Chevy C/10 6.0L 4L80 373 locker

02-03-2015, 08:10 PM	#5
65standard Registered User Join Date: Dec 2014 Location: Coal City, IL Posts: 695	Re: Drum/drum brakes??? I guess that is what was cut out of the brake system when the truck lived in the junkyard. Any clue as where I can get one of these? Look like a chevy dealer only part. Then again, I doubt a dealer would be able to get a 45 year old part. __________________ Tony Nicholas @ Midwest Metal Masters 1953 Chevy 3100 392 Hemi w/727 & 9” Ford 1985 Chevy C/10 6.0L 4L80 373 locker

02-03-2015, 09:47 PM	#7
65standard Registered User Join Date: Dec 2014 Location: Coal City, IL Posts: 695	Re: Drum/drum brakes??? Thank you, I appreciate the links. __________________ Tony Nicholas @ Midwest Metal Masters 1953 Chevy 3100 392 Hemi w/727 & 9” Ford 1985 Chevy C/10 6.0L 4L80 373 locker

02-04-2015, 02:10 AM	#9
jocko Senior Member Join Date: Oct 2009 Location: Godley, TX Posts: 17,939	Re: Drum/drum brakes??? LMC sells them. Over $200 last time I bought one though... Distro block also provides the signal for your dash brake light - indicates when one circuit has been lost - safety feature.

02-04-2015, 07:27 AM	#10
Don Quixote Registered User Join Date: May 2008 Location: Woodlawn, TN Posts: 275	Re: Drum/drum brakes??? www.classicparts.com has the distribution blocks for drum/drum for $80. They're out there and they're not expensive. I recently replaced mine. __________________ Rocinante: 1972 GMC C25, 292, SM465, 14 bolt, power nothing, 440k and still handles my PCS moves Jorge: Kia Roller-skate with lots of buttons for the wife Wovoka: 2017 Indian Chief Vintage, better on gas but not much So far, this is the oldest I've ever been.

02-04-2015, 08:47 PM	#11
RodnRudy Senior Member Join Date: Oct 2014 Location: New Palestine In Posts: 930	Re: Drum/drum brakes??? I've got a distribution block laying on the floor of my garage, took it off my running driving 68 C10 truck. Upgrading to disc brakes so I've got all new stuff. It's free to you if you PM me your address. Phil

02-04-2015, 09:01 PM	#12
65standard Registered User Join Date: Dec 2014 Location: Coal City, IL Posts: 695	Re: Drum/drum brakes??? Thank you Phil, much appreciated. I'll PM you. __________________ Tony Nicholas @ Midwest Metal Masters 1953 Chevy 3100 392 Hemi w/727 & 9” Ford 1985 Chevy C/10 6.0L 4L80 373 locker



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