Four Wheel Disk Brake Master Cylinder - The 1947 - Present Chevrolet & GMC Truck Message Board Network

UNCLEBOB · 03-21-2003, 11:10 PM

What master cylinder would I use on my 68 converted to four wheel disk brakes it has manual brakes. THANKS

nu2-72 · 03-21-2003, 11:41 PM

I have done some research into this.
The truck master for 71-72 is for front disc only and has a 7/8" bore.
Corvettes are factory four wheel disc and have a 1" bore.
I plan to use one from a 1976 Corvette that I have left over from a restoration. I will also use the Vette prop valve.

Mike C · 03-21-2003, 11:55 PM

The 'vette master was going to be my suggestion as well, but another good one is a 79-81 WS6 TransAM that had factory rear discs. It might be more inline with your needs depending on what calipers you have.

still w.i.p '68 · 03-22-2003, 12:14 AM

on black72"s truck, he used a master clyinder, and booster off of about a 90 chevy truck,I believe, and the disk brake rear end he used was out of a caprice cop car, and he used the prop valve from it also, seems to work great, these are junk yard parts, and sound alot cheaper than anything that says corvette...lots of luck

UNCLEBOB · 03-22-2003, 01:20 AM

The trans am has a 1 1/8 bore. decisions decisions?

nate68 · 03-25-2003, 04:39 AM

i use a 76 vette master, works great

Frank_Zeller · 03-25-2003, 10:19 AM

Find a master with 1 inch or less bore. The 81 TA uses the newer style aluminum master that is 25mm bore. Brake proportioning valve from a 1977-1978 Seville with 4-wheel disc. The newer style masters have the lines reverse. Brake vacuum booster from 1983-1987 Regal/Cutlass works with the newer style masters and bolts to our trucks. I have all this stuff but have yet to take on the conversion.

Good place to look up master cylinder bore diameter

www.partsamerica.com

good info here

http://home.pacbell.net/bigiron/Arti...rRearDisc.html

Mike C · 03-25-2003, 11:12 AM

Thanks for those links Frank. They do not show a 302 powered 69 Camaro to look up the disc/drum Z/28 master. They show two different Corvette masters, a 1 1/8" for power brakes and a 1" for manual brakes.

For the 80 Trans Am, they show a 1" bore for manual brakes. Not sure on the depth of pushrod hole on power vs. manual mc, but on my '69 Camaro I have a Z/28 power disc master actuated manually with no problems, so there appears to be several options.

dmec · 03-25-2003, 03:31 PM

the trans am master is the same as cad seville. both are for power brakes. corvette is the only manual disc master i know of.

Mike C · 03-25-2003, 05:57 PM

Like I said, if you go to partsamerica.com and look at a 1980 firebird 4 wheel disc, it shows a 1" bore master for manual.

blazunfool · 03-26-2003, 12:09 AM

The one I am using on my 4wheel disc conversion is off a 77-79 caddy seville. Those cars had 4 wheel disc brakes and the reserviors are the same size front and rear. Also it seems to have the same mounting and piston depth as the one on the truck with power brakes and disc/drum.

Low69CST · 03-26-2003, 01:02 AM

I talked to the guys at ECE, they used the stock truck booster and mastercylinder and said it worked fine.

03-21-2003, 11:10 PM	#1
UNCLEBOB Registered User Join Date: May 2000 Location: bremerton wa 98310 Posts: 100	Four Wheel Disk Brake Master Cylinder What master cylinder would I use on my 68 converted to four wheel disk brakes it has manual brakes. THANKS __________________ 68 lwb 383 solid roller,250dur, 582lift, afr 210s, 10.8 comp. edel.rpm, 750vs,1 3/4 headers turbo 400, 3500 stall,ford 9 inch 3.89 gears

03-21-2003, 11:41 PM	#2
nu2-72 Senior Member Join Date: Apr 2001 Location: Amazonia, Mo. USA Posts: 2,821	I have done some research into this. The truck master for 71-72 is for front disc only and has a 7/8" bore. Corvettes are factory four wheel disc and have a 1" bore. I plan to use one from a 1976 Corvette that I have left over from a restoration. I will also use the Vette prop valve. __________________ 72 3/4 4x4 350 4spd 72 3/4 4x4 350 auto 2004 Duramax Silverado 4x4 2006 Duramax Crew cab 4x4 2010 Harley Ultra Limited 2011 Harley Street Glide

03-21-2003, 11:55 PM	#3
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,728	The 'vette master was going to be my suggestion as well, but another good one is a 79-81 WS6 TransAM that had factory rear discs. It might be more inline with your needs depending on what calipers you have. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

03-22-2003, 12:14 AM	#4
still w.i.p '68 Dreams are free Join Date: Dec 2002 Location: Hogansville Texas Posts: 546	on black72"s truck, he used a master clyinder, and booster off of about a 90 chevy truck,I believe, and the disk brake rear end he used was out of a caprice cop car, and he used the prop valve from it also, seems to work great, these are junk yard parts, and sound alot cheaper than anything that says corvette...lots of luck __________________ '68 swb fleetside originally w.i.p '68 member since 1-01 w.i.p = ( work in progress )

03-22-2003, 01:20 AM	#5
UNCLEBOB Registered User Join Date: May 2000 Location: bremerton wa 98310 Posts: 100	The trans am has a 1 1/8 bore. decisions decisions? __________________ 68 lwb 383 solid roller,250dur, 582lift, afr 210s, 10.8 comp. edel.rpm, 750vs,1 3/4 headers turbo 400, 3500 stall,ford 9 inch 3.89 gears

03-25-2003, 04:39 AM	#6
nate68 Registered User Join Date: Jan 2000 Location: ca Posts: 1,110	i use a 76 vette master, works great __________________ 68 short step, 406/700r4, 9" w/discs.

03-25-2003, 10:19 AM	#7
Frank_Zeller Registered User Join Date: Jun 2001 Location: Austin, Texas Posts: 796	Find a master with 1 inch or less bore. The 81 TA uses the newer style aluminum master that is 25mm bore. Brake proportioning valve from a 1977-1978 Seville with 4-wheel disc. The newer style masters have the lines reverse. Brake vacuum booster from 1983-1987 Regal/Cutlass works with the newer style masters and bolts to our trucks. I have all this stuff but have yet to take on the conversion. Good place to look up master cylinder bore diameter www.partsamerica.com good info here http://home.pacbell.net/bigiron/Arti...rRearDisc.html __________________ 69 SWB C/10 5-6 drop 700R4 69 Firebird Convert 455 4 spd 70 Torino GT Convert Austin-Texas

03-25-2003, 11:12 AM	#8
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,728	Thanks for those links Frank. They do not show a 302 powered 69 Camaro to look up the disc/drum Z/28 master. They show two different Corvette masters, a 1 1/8" for power brakes and a 1" for manual brakes. For the 80 Trans Am, they show a 1" bore for manual brakes. Not sure on the depth of pushrod hole on power vs. manual mc, but on my '69 Camaro I have a Z/28 power disc master actuated manually with no problems, so there appears to be several options. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

03-25-2003, 03:31 PM	#9
dmec Senior Member Join Date: Jun 2000 Location: yucaipa ca Posts: 580	the trans am master is the same as cad seville. both are for power brakes. corvette is the only manual disc master i know of.

03-25-2003, 05:57 PM	#10
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,728	Like I said, if you go to partsamerica.com and look at a 1980 firebird 4 wheel disc, it shows a 1" bore master for manual. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

03-26-2003, 12:09 AM	#11
blazunfool Registered User Join Date: Jan 2003 Location: WESTMINSTER, MD Posts: 60	The one I am using on my 4wheel disc conversion is off a 77-79 caddy seville. Those cars had 4 wheel disc brakes and the reserviors are the same size front and rear. Also it seems to have the same mounting and piston depth as the one on the truck with power brakes and disc/drum. __________________ 72 2wd Blazer 305TBI/700r4., 69 C10 SWB 400SB TPI, 400trans, Step side ., 72 4WD Blazer 350 TBI, 350 serp. drive & "Old Air" ., 94 Camaro Z28 LT1., 94 Grand Cherokee V8, 95 Grand Cherokee 6cyl.

03-26-2003, 01:02 AM	#12
Low69CST Registered User Join Date: May 2000 Location: Frankfort, Kentucky, USA Posts: 2,163	I talked to the guys at ECE, they used the stock truck booster and mastercylinder and said it worked fine. __________________ '69 CST Short fleetside Lowered, 400 small block, 700R4, 4 wheel disc brakes, front sway bar & rear camaro sway bar (in progress) '87 V10 4x4 Short Fleetside Quad Suspension and Dual Tanks



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