Rear Discs - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jbw0127 · 11-05-2004, 01:14 PM

To those who have converted to rear discs.

Did you stay with your original master and just install an adjustable prop. valve. (my master is disc/drum)

Recently I was told that I needed to get a disc/disc master and maybe a disc/disc proportioning valve and also install 2psi residual valves for the front and back (thought these are mainly for systems with the master lower than the calipers).

I just wanna get it right the first time and not dick with it later!

jbw0127 · 11-06-2004, 09:17 PM

ttt

roj2323 · 11-07-2004, 01:55 AM

i have simular question so i will add it here instead of a new thread.

for those who have converted there rear ends to disk where did you get your kit and or parts?
thanks,
ondrew

BobbyK · 11-07-2004, 02:22 AM

Check out this thread.
CLICKY

**GMCPaul** · 11-07-2004, 04:39 AM

Your not optimizing the disc/disc setup unless you use a disc/disc master cylinder & disc/disc prop valve or adjustable prop valve. The brakes will work as good or better going disc/disc over disc/drum while keeping a disc/drum master & prop valve but they will not work as well as with the disc/disc master & prop valve. The residual pressure valves however are not needed, they only need to be used when the master cylinder is located below the calipers such as under the floor on early trucks and they only act as a check valve to prevent the fluid from overflowing the master cylinder.
The best route in our opinion is a disc/disc master cylinder with a adjustable valve on rear line and nothing on front line so it receives full pressure to the front brakes, then dial down the rear brake pressure until you no longer lock up and braking brings you to a smooth stop. If your rear brake pressure it set slightly high on rear instead of stopping smooothly the brakes feel ultra touchy and want to grab suddenly.
GMCPaul

gmc67swb · 11-07-2004, 10:44 AM

GMC Paul, do you have a complete kit to do this swap front and back? Mine is a '67 GMC with the Dana 44 out back originally equipped with drum/drum and 6 lugs. Would like to go to 5 lugs and lower the truck in the process. Sorry, not trying to hyjack this thread.

roj2323 · 11-07-2004, 01:41 PM

interesting articals.

jbw0127 · 11-09-2004, 12:15 PM

GMCPaul or whoever......

What master cylinder do you recommend and will bolt up to the stock power booster?

**raggedjim** · 11-09-2004, 12:47 PM

68-mid seventies corvette worked for me... I used a disc/disc combo valve from CPP, works like crazy...

11-05-2004, 01:14 PM	#1
jbw0127 Registered User Join Date: Nov 2003 Location: Sacramento, CA Posts: 73	Rear Discs To those who have converted to rear discs. Did you stay with your original master and just install an adjustable prop. valve. (my master is disc/drum) Recently I was told that I needed to get a disc/disc master and maybe a disc/disc proportioning valve and also install 2psi residual valves for the front and back (thought these are mainly for systems with the master lower than the calipers). I just wanna get it right the first time and not dick with it later! __________________ 72 swb Cheyenne "nut & bolt" frame off (in process) Blown 383

11-06-2004, 09:17 PM	#2
jbw0127 Registered User Join Date: Nov 2003 Location: Sacramento, CA Posts: 73	Ttt ttt __________________ 72 swb Cheyenne "nut & bolt" frame off (in process) Blown 383

11-07-2004, 02:22 AM	#4
BobbyK Registered User Join Date: May 2000 Location: Petrolia,Ontario,Canada but working in Port Huron,Mi. Posts: 1,772	Check out this thread. CLICKY __________________ 71 blazer,350SBC,approx.375HP,700R4,factory GM TPI.Dual electric fans,33x12.5x15 ATR on stock suspension. Petrolia,Ontario,Canada but working in Port Huron,MI. See ALL my Blazer pic's HERE

11-07-2004, 04:39 AM	#5
GMCPaul Senior Member Join Date: Mar 2000 Location: Rockville,In. USA Posts: 3,721	Your not optimizing the disc/disc setup unless you use a disc/disc master cylinder & disc/disc prop valve or adjustable prop valve. The brakes will work as good or better going disc/disc over disc/drum while keeping a disc/drum master & prop valve but they will not work as well as with the disc/disc master & prop valve. The residual pressure valves however are not needed, they only need to be used when the master cylinder is located below the calipers such as under the floor on early trucks and they only act as a check valve to prevent the fluid from overflowing the master cylinder. The best route in our opinion is a disc/disc master cylinder with a adjustable valve on rear line and nothing on front line so it receives full pressure to the front brakes, then dial down the rear brake pressure until you no longer lock up and braking brings you to a smooth stop. If your rear brake pressure it set slightly high on rear instead of stopping smooothly the brakes feel ultra touchy and want to grab suddenly. GMCPaul __________________ Secure Online Catalog for-GMCPauls Truck Parts Email- GMCPAULS@GMAIL.COM

11-07-2004, 10:44 AM	#6
gmc67swb Registered User Join Date: Feb 2003 Location: Mesquite, Tx Posts: 396	GMC Paul, do you have a complete kit to do this swap front and back? Mine is a '67 GMC with the Dana 44 out back originally equipped with drum/drum and 6 lugs. Would like to go to 5 lugs and lower the truck in the process. Sorry, not trying to hyjack this thread. __________________ GM 330HP/350, Magnuson 122HH, Tremec TKO 5spd

11-07-2004, 01:55 AM	#3
roj2323 Senior Member Join Date: Mar 2004 Location: Somewhere Posts: 985	i have simular question so i will add it here instead of a new thread. for those who have converted there rear ends to disk where did you get your kit and or parts? thanks, ondrew

11-07-2004, 01:41 PM	#7
roj2323 Senior Member Join Date: Mar 2004 Location: Somewhere Posts: 985	interesting articals.

11-09-2004, 12:15 PM	#8
jbw0127 Registered User Join Date: Nov 2003 Location: Sacramento, CA Posts: 73	What master? GMCPaul or whoever...... What master cylinder do you recommend and will bolt up to the stock power booster? __________________ 72 swb Cheyenne "nut & bolt" frame off (in process) Blown 383

11-09-2004, 12:47 PM	#9
raggedjim Senior Member Join Date: Jun 2002 Location: Murray, Kentucky Posts: 3,514	68-mid seventies corvette worked for me... I used a disc/disc combo valve from CPP, works like crazy... __________________ Roger '68 Short step - https://67-72chevytrucks.com/vboard/...d.php?t=849675 '69 ('70?) 2wd Blazer '70 GMC Jimmy 2wd '73 Firebird - https://67-72chevytrucks.com/vboard/...d.php?t=853203 Ideas - https://67-72chevytrucks.com/vboard/...d.php?t=851743



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