Another brake booster question. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

REPO1 · 07-11-2002, 12:31 AM

Can a brake booster from a '70 that had drum/drum brakes, be used on a disc/drum truck if I installe the disc/drum master onto it?

Basically I'm asking if it was the same booster on each truck with just a master change?

Longhorn Man · 07-11-2002, 12:32 AM

The booster is not the same. I tried a disk drum booster on a drum drum truck..couldn't get it.

Scrub · 07-11-2002, 01:05 AM

Hmmm...
I never thought the booster made that much difference, just the master cylinder.
I think the real important thing is having the disc proportioning valve and the corect master cylinder.

Good luck.

poff · 07-12-2002, 06:54 PM

The boosters and brackets are different. You can get the brackets off of any 70-72 truck with discs. 1/2 tons and 3/4 tons have different boosters but 1/2 tons, 3/4 tons and 2wd/4wd have the same brackets. The lower brace is longer on the 3/4 tons and they have one extra brace on the side.

Longhorn Man · 07-12-2002, 07:01 PM

The rods inside are not the same either.
And actually, it is 71 and 72..not 70, they still had drums.

BigBlockBurris · 07-12-2002, 09:42 PM

I will have to politely disagree with you cannot use a drum/drum booster on a disc/drum truck. I have used drum/drum boosters on several trucks and never had one problem. I have a friend with a 70 1 ton flat bed with factory power brakes and he put a 1 ton disc set up on the front and never changed the proportioning valve or anything and I can personally say it will stand you on your head. I know that the 1/2 ton and 3/4 ton are different even those all bolt up the same because I just put a 1/2 ton cab on my 3/4 ton and removed the 1/2 ton booster and used my 3/4 ton booster and I have excellent brakes (even better than before).
Just my 2 Cents worth.

BBB

Longhorn Man · 07-12-2002, 09:55 PM

Interesting. I tried putting a 72 booster on a 70 that was still set up for drums....it was a big no go. nothing lined up. i fought and cussed for hrs. I just ended up going to my storage unit and getting the 70 3/4 ton booster and slapping it onto the 70 one ton. Bolted on with no cussing, nor bleeding.

robby · 07-12-2002, 11:06 PM

I have a 70 C10 that I want to put a 71 booster on. will it work?

*racedvl* · 07-12-2002, 11:15 PM

Andy.......please re-read your first post. Exp. your spelling....

Longhorn Man · 07-13-2002, 12:06 AM

OMG! and it didn't edit it on it's own!
thanks jason.

**phase_one** · 07-13-2002, 12:09 AM

I put a 72 booster and master on my 70. I used the orginal proportioning valve. The set up works for me.

poff · 07-17-2002, 06:47 PM

Quote:

Originally posted by longhornmail
The rods inside are not the same either.
And actually, it is 71 and 72..not 70, they still had drums.

Discs were an option in '70. I've never seen one but apparently they were available. I got all the brackets off of a 3/4 ton with discs and the rod was the same as my drum rod. It is possible that there are more than one drum rod. I have heard of people successfully using different combinations of drum and disc parts together. I am just stating the difference if you use the stock disc parts from a 70-72 truck.

Longhorn Man · 07-17-2002, 08:08 PM

Looking at my dated factory paper work, there were no discs untill the model year '71. A '71 made in late '70 would have them, but there was no option. You may have seen a truck updated with them though.

1-PU70 · 07-18-2002, 04:38 PM

There is a differance between 3/4 and 1/2 ton boosters. You can use a 71 or 72 1/2 ton a 70.

johnnyp · 07-18-2002, 04:47 PM

Well, we certainly cleared that up.

RALLY FAST · 07-19-2002, 07:31 AM

i have a 3/4 ton booster 69or 70 can i put it on my 69 1/2 ton?

Woody · 07-19-2002, 07:48 AM

While I have not done anything yet on my drum to disk swap, I bought some parts from a board member a few years back and inthe deal he threw in a booster w/master cyc for disk brake front end. I currently have power drums all around and the p/n's on the boosters are the same. So I'm assuming they will work after I swap the rods between the booster and master cyc. Both are 1/2 ton.

imdarren · 07-19-2002, 01:57 PM

I took a 3/4 ton booster from a 69 drum/drum truck, and it worked perfect on my 72 1/2 ton. I did toss the master cylinder from the 69, and just used the Master Cylinder and preportioning valve that my 72 Disk/Drum setup already had. It works great!! No modifications.
Maybe the problem occurs when you use a newer booster on an older truck. ie: a 72 booster on a 6x truck?

Really Fast. Yes. You can use the booster from the 3/4 ton. The 3/4 ton booster is a dual diphram booster, and will help your truck stop better.

Sorry this thread is so confusing.
Darren

REPO1 · 07-19-2002, 02:09 PM

Good to know. This is helping alot.

Thanks!

07-11-2002, 12:31 AM	#1
REPO1 Shortbox wanna-be. Join Date: Mar 2002 Location: Fort St.John, British Columbia, Canada Posts: 773	Another brake booster question. Can a brake booster from a '70 that had drum/drum brakes, be used on a disc/drum truck if I installe the disc/drum master onto it? Basically I'm asking if it was the same booster on each truck with just a master change? __________________ 1970 Chevy C20 Custom Camper 402BB Turbo 400 trans. (Slowly becoming a '70 shortbox 1/2 ton) '71 Camaro SS 402/T400 resto '97 Z28 (11.41@127MPH)

07-11-2002, 12:32 AM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	The booster is not the same. I tried a disk drum booster on a drum drum truck..couldn't get it. Last edited by Longhorn Man; 07-13-2002 at 12:06 AM.

07-11-2002, 01:05 AM	#3
Scrub Collector of rusty Items Join Date: Dec 2001 Location: Sisters,Oregon USA Posts: 731	Hmmm... I never thought the booster made that much difference, just the master cylinder. I think the real important thing is having the disc proportioning valve and the corect master cylinder. Good luck. __________________ Scrub Sisters, Oregon - Home of the Sisters Rodeo. 70 GMC 1,000,000 + miles 72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.

07-12-2002, 06:54 PM	#4
poff Registered User Join Date: Dec 1999 Location: san diego, ca Posts: 546	The boosters and brackets are different. You can get the brackets off of any 70-72 truck with discs. 1/2 tons and 3/4 tons have different boosters but 1/2 tons, 3/4 tons and 2wd/4wd have the same brackets. The lower brace is longer on the 3/4 tons and they have one extra brace on the side. __________________ '70 K-20 San Diego, CA

07-12-2002, 11:06 PM	#8
robby Semper Fidelis Join Date: Dec 2001 Location: Cedar City, Utah Posts: 654	I have a 70 C10 that I want to put a 71 booster on. will it work? __________________ 72 Chevy C 20 with 402 For sale 85 GMC K2500 83 Trans Am Cedar City, Utah (Missouri Native)

07-12-2002, 07:01 PM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	The rods inside are not the same either. And actually, it is 71 and 72..not 70, they still had drums.

07-12-2002, 09:42 PM	#6
BigBlockBurris Registered User Join Date: Nov 2001 Location: Concord,NC,USA Posts: 743	I will have to politely disagree with you cannot use a drum/drum booster on a disc/drum truck. I have used drum/drum boosters on several trucks and never had one problem. I have a friend with a 70 1 ton flat bed with factory power brakes and he put a 1 ton disc set up on the front and never changed the proportioning valve or anything and I can personally say it will stand you on your head. I know that the 1/2 ton and 3/4 ton are different even those all bolt up the same because I just put a 1/2 ton cab on my 3/4 ton and removed the 1/2 ton booster and used my 3/4 ton booster and I have excellent brakes (even better than before). Just my 2 Cents worth. BBB

07-12-2002, 09:55 PM	#7
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Interesting. I tried putting a 72 booster on a 70 that was still set up for drums....it was a big no go. nothing lined up. i fought and cussed for hrs. I just ended up going to my storage unit and getting the 70 3/4 ton booster and slapping it onto the 70 one ton. Bolted on with no cussing, nor bleeding.

07-12-2002, 11:15 PM	#9
racedvl Account Suspended Join Date: Jan 2000 Location: Woodstock, IL Posts: 7,020	Andy.......please re-read your first post. Exp. your spelling....

07-13-2002, 12:06 AM	#10
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	OMG! and it didn't edit it on it's own! thanks jason.

07-13-2002, 12:09 AM	#11
phase_one Registered User Join Date: Jul 2001 Location: Praireville. LA 70769 Posts: 390	I put a 72 booster and master on my 70. I used the orginal proportioning valve. The set up works for me. __________________ 11 Surbaban 70 C 10 still in progress

07-17-2002, 08:08 PM	#13
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Looking at my dated factory paper work, there were no discs untill the model year '71. A '71 made in late '70 would have them, but there was no option. You may have seen a truck updated with them though.

07-18-2002, 04:38 PM	#14
1-PU70 Registered User Join Date: Apr 2000 Location: Bradenton, FL Posts: 1,036	There is a differance between 3/4 and 1/2 ton boosters. You can use a 71 or 72 1/2 ton a 70. __________________ 1970 CST/10 402,700R4,3:73 posi,AC,PS,PB,TLT,PW,Buckets with heaters

07-18-2002, 04:47 PM	#15
johnnyp Keepin' It Stock Join Date: Aug 2001 Location: Grand Island, Nebraska, USA Posts: 554	Well, we certainly cleared that up. __________________ 72 Sierra Grande - Maych Forget about "do it right the first time". Do it wrong the first time to learn how, then do it right the second time.

07-19-2002, 07:31 AM	#16
RALLY FAST Registered User Join Date: Apr 2002 Location: knox, Tenn. Posts: 150	i have a 3/4 ton booster 69or 70 can i put it on my 69 1/2 ton? __________________ 69 SHORT FLEET SIDE MAROON RESTORED. 71 LONG FLEET RESTORED D/DRIVER. BUT ALWAYS LOOKING TO IMPROVE 68 SHORT UNDER CONSTRUCTION



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07-19-2002, 07:48 AM	#17
Woody Registered User Join Date: Feb 2000 Location: Georgetown, KY, USA Posts: 631	While I have not done anything yet on my drum to disk swap, I bought some parts from a board member a few years back and inthe deal he threw in a booster w/master cyc for disk brake front end. I currently have power drums all around and the p/n's on the boosters are the same. So I'm assuming they will work after I swap the rods between the booster and master cyc. Both are 1/2 ton.

07-19-2002, 01:57 PM	#18
imdarren Registered User Join Date: Oct 2001 Location: SW Washington Posts: 1,006	I took a 3/4 ton booster from a 69 drum/drum truck, and it worked perfect on my 72 1/2 ton. I did toss the master cylinder from the 69, and just used the Master Cylinder and preportioning valve that my 72 Disk/Drum setup already had. It works great!! No modifications. Maybe the problem occurs when you use a newer booster on an older truck. ie: a 72 booster on a 6x truck? Really Fast. Yes. You can use the booster from the 3/4 ton. The 3/4 ton booster is a dual diphram booster, and will help your truck stop better. Sorry this thread is so confusing. Darren __________________ Washington State 1967 Chevy C10 LWB Rodstoration In Progress. 1972 K20 Cheyenne Super Last edited by imdarren; 07-19-2002 at 02:01 PM.

07-19-2002, 02:09 PM	#19
REPO1 Shortbox wanna-be. Join Date: Mar 2002 Location: Fort St.John, British Columbia, Canada Posts: 773	Good to know. This is helping alot. Thanks! __________________ 1970 Chevy C20 Custom Camper 402BB Turbo 400 trans. (Slowly becoming a '70 shortbox 1/2 ton) '71 Camaro SS 402/T400 resto '97 Z28 (11.41@127MPH)

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