Power Brakes Conversion Help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

wareagle_1997 · 10-11-2006, 06:03 PM

I am restoring a 70 SWB and wanted to convert my manual brakes to power brakes. There are four mounting studs coming out of the firewall that are 2 1/2 inches apart from center to center. My manual master cylinder is only using the bottom two studs, and there is a hole in the firewall centered exactly between these bottom two studs. The problem that I have is that every power booster that I've come across from Napa to Autozone to LMC has studs coming out of the power booster that are 3 1/2 inches, center to center, and the pushrod is directly centered in the four bolt pattern, not centered with the bottom two bolts. But I have every reason to believe that I have a completely stock setup. Can anyone tell me what I'm missing here?

70GMCer · 10-11-2006, 06:09 PM

You need the mounting brackets and rod that mount to those studs that are on the booster. Then it will bolt up to the firewall.

wareagle_1997 · 10-11-2006, 06:14 PM

Where would I find that?

So would all 67-72's with stock power brakes require the mounting brakets and rod, or is this strictly a conversion issue?

Thanks for the help!

**truckdude239** · 10-11-2006, 07:42 PM

check the parts borad or surcibe for 25 buxs and post a wtb

centsless · 10-11-2006, 07:47 PM

All of the 67-72 trucks with power brakes have an adapter/bellcrank assy the bolts to the firewall, then the booster bolts to the adapter.

mbgmike · 10-11-2006, 07:53 PM

heres ours

stainless are 28.00

plated $15.00

You will also need a disc/drum prop valve

John @ BROTHERS · 10-11-2006, 07:54 PM

Here is a pic of the bracket you need.

BLACK AND BLUE 67-72 · 10-11-2006, 09:02 PM

Are there any vendors that sell the original style brackets, or the rod that connects to the brake pedal?

**Bob B.** · 10-13-2006, 01:15 AM

Careful! '67-'70 trucks with 4 wheel drums use Bendix boosters, '71-'72 trucks with front disc brakes use Delco boosters. The Bendix booster uses different brackets and linkage than the Delco booster does.

BowTieOgre · 10-13-2006, 09:05 AM

Quote:

Originally Posted by mbgmike

heres ours

stainless are 28.00

plated $15.00

You will also need a disc/drum prop valve

Are you going to be at the Moultrie, GA swap meet by chance?

mbgmike · 10-13-2006, 06:16 PM

Quote:

Originally Posted by BowTieOgre

Are you going to be at the Moultrie, GA swap meet by chance?

No but the Alex from outr Va location is going to one around Richmond Va this weekend.

High Speed low Drag · 10-13-2006, 08:48 PM

Where around Richmond? Any idea?

dougs69c10 · 10-13-2006, 11:28 PM

I ran into the problem of using the 69 booster with the bracket from a 71 and it was a simple fix, I just attached the booster to the firewall loosely, then attached the booster to the bracket then tightend them down, it worked like a charm, and i cant tell a problem at all when steppin on the whoa peddle.

mbgmike · 10-14-2006, 08:22 AM

Quote:

Originally Posted by High Speed low Drag

Where around Richmond? Any idea?

He told me but I forgot. I know its in Midlothian. I tried to call him but you can call him at 800-398-0537 and talk to ALex. Or call 804-937-3729. Its a small meet nothing big.

Its off Hwy 360 west of Richmond at a place called "Tractor Supply Company"

10-11-2006, 06:03 PM	#1
wareagle_1997 Registered User Join Date: May 2006 Location: Memphis, TN Posts: 5	Power Brakes Conversion Help I am restoring a 70 SWB and wanted to convert my manual brakes to power brakes. There are four mounting studs coming out of the firewall that are 2 1/2 inches apart from center to center. My manual master cylinder is only using the bottom two studs, and there is a hole in the firewall centered exactly between these bottom two studs. The problem that I have is that every power booster that I've come across from Napa to Autozone to LMC has studs coming out of the power booster that are 3 1/2 inches, center to center, and the pushrod is directly centered in the four bolt pattern, not centered with the bottom two bolts. But I have every reason to believe that I have a completely stock setup. Can anyone tell me what I'm missing here?

10-11-2006, 06:09 PM	#2
70GMCer Senior Member Join Date: Apr 2005 Location: Joppa, Maryland Posts: 4,408	Re: Power Brakes Conversion Help You need the mounting brackets and rod that mount to those studs that are on the booster. Then it will bolt up to the firewall. __________________ 1997 GMC Sierra Ext 1965 Mustang Last edited by 70GMCer; 10-11-2006 at 06:10 PM.

10-11-2006, 06:14 PM	#3
wareagle_1997 Registered User Join Date: May 2006 Location: Memphis, TN Posts: 5	Re: Power Brakes Conversion Help Where would I find that? So would all 67-72's with stock power brakes require the mounting brakets and rod, or is this strictly a conversion issue? Thanks for the help!

10-11-2006, 07:42 PM	#4
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,238	Re: Power Brakes Conversion Help check the parts borad or surcibe for 25 buxs and post a wtb __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

10-11-2006, 07:47 PM	#5
centsless sufficiently talented fool Join Date: Jun 2006 Location: Forest Hill, MD Posts: 2,231	Re: Power Brakes Conversion Help All of the 67-72 trucks with power brakes have an adapter/bellcrank assy the bolts to the firewall, then the booster bolts to the adapter. __________________ "it's impossible to be surrounded by idiots when you are part of the circle" 2003 Suburban 2002 Pontiac Montana 1981 Corvette 1966 Impala Convertible Click here to support the board

10-11-2006, 07:53 PM	#6
mbgmike Registered User Join Date: Aug 2005 Location: Pasadena,Tx /Pto Pta DR Posts: 5,415	Re: Power Brakes Conversion Help heres ours stainless are 28.00 plated $15.00 You will also need a disc/drum prop valve Attached Images Last edited by mbgmike; 10-11-2006 at 07:55 PM.

10-11-2006, 07:54 PM	#7
John @ BROTHERS Registered User Join Date: Jul 2000 Location: Corona, CA Posts: 310	Re: Power Brakes Conversion Help Here is a pic of the bracket you need. __________________ 1967 Chevy Short/Fleet 1969 Chevy Short/Step 2004.5 Dodge 2500 4x4 Cummins 6spd

10-11-2006, 09:02 PM	#8
BLACK AND BLUE 67-72 Firefighter Join Date: Feb 2001 Location: Yellville, Ar, USA Posts: 1,943	Re: Power Brakes Conversion Help Are there any vendors that sell the original style brackets, or the rod that connects to the brake pedal? __________________ '72 Chevy SWB 350 Auto '67 GMC LWB 350 4 speed '70 Chevy 4x4 Stepside 350 Auto Yellville, Ar. USA

10-13-2006, 01:15 AM	#9
Bob B. Senior Member Join Date: Aug 2005 Location: Los Angeles Posts: 1,386	Re: Power Brakes Conversion Help Careful! '67-'70 trucks with 4 wheel drums use Bendix boosters, '71-'72 trucks with front disc brakes use Delco boosters. The Bendix booster uses different brackets and linkage than the Delco booster does. __________________ 1967 GMC CM-2500 Camper Cruiser, 351E V-6, NP 435 4 speed, Dana 60, and factory A/C. 2012 GMC K-3500 WT regular cab, 6.0L Vortec, 6L90.

10-13-2006, 08:48 PM	#12
High Speed low Drag Registered User Join Date: Sep 2006 Location: Mechanicsville, Virginia Posts: 53	Re: Power Brakes Conversion Help Where around Richmond? Any idea?

10-13-2006, 11:28 PM	#13
dougs69c10 Registered User Join Date: Feb 2006 Location: Birmingham,Alabama Posts: 260	Re: Power Brakes Conversion Help I ran into the problem of using the 69 booster with the bracket from a 71 and it was a simple fix, I just attached the booster to the firewall loosely, then attached the booster to the bracket then tightend them down, it worked like a charm, and i cant tell a problem at all when steppin on the whoa peddle. __________________ 1969 c10 stepside 250 inline six, 4speed granny tranny, 4.11 posi rear end

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