Brake Vac Booster -Disc Brake C10 and C20 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

CCCC · 07-01-2008, 05:26 PM

I need a new booster unit for a BB C20 (front disc brakes) and a seemingly knowledgeable fellow recently told me that the two types seen on 71 and 72 C10s and C20s are interchageable. It has appeared to me that the C10 vac tank unit is a bit thinner and slopes a bit from front to back on the perimeter, and that the C20 unit is a bit thicker and straight from front to back on its edge. Is this the case? And, are these two units interchangeable for use on either the C10 or C20? Thanks in advance for any insights. CCCC

**john** · 07-01-2008, 06:07 PM

The c-10 booster is single diaphragm, and the c-20 is double diaphragm. I would stick with the double for a c-20.

Longhorn Man · 07-01-2008, 11:17 PM

agreed.
They CAN be swapped out, but why downgrade your brakes?

CCCC · 07-02-2008, 12:10 AM

Thanks guys, for the usual quick and informative reply. After measuring I could see that either should fit, but knew there had to be a reason for the difference in shape/size. Of course, I will stay with the double diaphragm unit.

07-01-2008, 05:26 PM	#1
CCCC Registered User Join Date: Mar 2007 Location: San Pedro River, SE Arizona Posts: 734	Brake Vac Booster -Disc Brake C10 and C20 I need a new booster unit for a BB C20 (front disc brakes) and a seemingly knowledgeable fellow recently told me that the two types seen on 71 and 72 C10s and C20s are interchageable. It has appeared to me that the C10 vac tank unit is a bit thinner and slopes a bit from front to back on the perimeter, and that the C20 unit is a bit thicker and straight from front to back on its edge. Is this the case? And, are these two units interchangeable for use on either the C10 or C20? Thanks in advance for any insights. CCCC __________________ CCCC 67 Sting Ray Coupe 327 4sp; 68 K10 Suburban 327 4sp; 69 K20 Lifted 383 4sp; 69 C80 Fire Truck 478 V6 5sp/2sp; 69 C20 Longhorn 327 4sp; 70 C30 Wrecker 350 4sp; 70 C30 Flat Bed 350 4sp; 71 C20 LWB 350 4sp; 72 K5 Blazer 350 4sp; 72 C30 Flat Bed Gooseneck Hauler with sleeper 350/TH400; 72 C20 Longhorn 402 4sp; 52 Mack LTL Supercharged Cummins 5sp x 3sp; 01 Dodge 5.9 HO Cummins 6spd; 02 Safari Trek 2430 8.1 Vortec on Workhorse Chassis; 03 Silverado 2500 HD 4wd Duramax/Allison Moved but still in the family 70 C20 Custom Camper 350/TH350; 72 K5 Blazer CST Highlander 350/TH350 Recently sent to new homes 72 C30 MoHome 402 4sp; 72 K5 Blazer Conv 350 4sp; 75 GMC 6000 Aerial 350 w Allison; 72 GMC 3500 Utility 350 4sp; 70 GMC 3500, 350 4sp

07-01-2008, 06:07 PM	#2
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Re: Brake Vac Booster -Disc Brake C10 and C20 The c-10 booster is single diaphragm, and the c-20 is double diaphragm. I would stick with the double for a c-20. __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/

07-01-2008, 11:17 PM	#3
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: Brake Vac Booster -Disc Brake C10 and C20 agreed. They CAN be swapped out, but why downgrade your brakes?

07-02-2008, 12:10 AM	#4
CCCC Registered User Join Date: Mar 2007 Location: San Pedro River, SE Arizona Posts: 734	Re: Brake Vac Booster -Disc Brake C10 and C20 Thanks guys, for the usual quick and informative reply. After measuring I could see that either should fit, but knew there had to be a reason for the difference in shape/size. Of course, I will stay with the double diaphragm unit. __________________ CCCC 67 Sting Ray Coupe 327 4sp; 68 K10 Suburban 327 4sp; 69 K20 Lifted 383 4sp; 69 C80 Fire Truck 478 V6 5sp/2sp; 69 C20 Longhorn 327 4sp; 70 C30 Wrecker 350 4sp; 70 C30 Flat Bed 350 4sp; 71 C20 LWB 350 4sp; 72 K5 Blazer 350 4sp; 72 C30 Flat Bed Gooseneck Hauler with sleeper 350/TH400; 72 C20 Longhorn 402 4sp; 52 Mack LTL Supercharged Cummins 5sp x 3sp; 01 Dodge 5.9 HO Cummins 6spd; 02 Safari Trek 2430 8.1 Vortec on Workhorse Chassis; 03 Silverado 2500 HD 4wd Duramax/Allison Moved but still in the family 70 C20 Custom Camper 350/TH350; 72 K5 Blazer CST Highlander 350/TH350 Recently sent to new homes 72 C30 MoHome 402 4sp; 72 K5 Blazer Conv 350 4sp; 75 GMC 6000 Aerial 350 w Allison; 72 GMC 3500 Utility 350 4sp; 70 GMC 3500, 350 4sp



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