Manual Disc Brake ?????? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

67sub · 11-25-2003, 03:49 PM

I am converting to 5 lug front disc brakes and remember seeing a thread about which master cylinders are usable. I will not have power brakes, but I am thinking that you can use a power master cylinder. Can anyone offer any tips or advice on this ?What will and what will not work? Thanks for any help - Curtis

krue · 11-25-2003, 04:12 PM

It's not that hard to put a booster on there and have the best of everything (except maybe rear discs). I would think you would need power to take advantage of the disc brakes.

Tx Firefighter · 11-25-2003, 04:37 PM

Curtis, plenty of the 71-72 trucks came with manual disc brakes. My 72 did. Just buy a non power master cylinder. O reilley has them for under 20 bucks

67sub · 11-25-2003, 05:10 PM

TX - That was my thought but I called oreilly,autozone and napa all said there was no listing for manual disc. Probably will get what they list and try it anyway.

The other question I have is proportion valve. Anybody sell them cheap? yahoo at oreilly said federal regulations would not let aftermarket manufacturers sell them because safety concerns

Also will the pushrod into the master cylinder that I currently have work?
Thanks for your help.

jimfulco · 11-25-2003, 11:06 PM

Tell them to get out the book & look it up, or go to a real parts place.

dinnut · 11-25-2003, 11:22 PM

most 71-72s didnt have the power booster and like all the 1/2 tons have front discs

**FRENCHBLUE72** · 11-25-2003, 11:38 PM

No booster's??? I have never seen a 71-72 with out the power booster. Add on's maybe, I doubt it.

krue · 11-25-2003, 11:41 PM

The point I was trying to make is why not use the booster, you can get the stuff you need for $50 or so and it only takes an hour or so to install, especially if you are going to take the master cylinder off anyways.

**FRENCHBLUE72** · 11-25-2003, 11:50 PM

I agree with krue if you do not have a booster then add one when you have everything apart,brake's are very important ...

Longhorn Man · 11-26-2003, 01:25 AM

Boosters are not really needed..just nice to have IMO. And if you have a wild cam...or plan on one sometime, then the booster can be a real pain in the dana. I had power brakes on the first longhorn and my cam made so little vacume that even an additional vacume canister only let me hit the brakes about 3 or 4 times before the pedal got hard.

That'll scare the crap outa you in bumper to bumper rush hr grid lock.

Don't know about teh disc set up, but the drum brakes has the same master power or non power.

An adjustable prop valve can be had through any performance catalog. Much better than a stock one since it is adjustable. Once you start playing with bigger tires in back it'll throw the stock parameters out the window.

cableguy0 · 11-26-2003, 01:28 AM

do not get a master for power disk and use it without a booster you will not be able to push the pedal and stop the truck. you have to use a non power master cylinder if your not using a booster

Tx Firefighter · 11-26-2003, 01:28 AM

Quote:

Originally posted by Longhorn Man
Once you start playing with bigger tires in back it'll throw the stock parameters out the window.

redneck!

Just hackin on ya man.

*redbowtie* · 11-26-2003, 04:37 AM

Quote:

Originally posted by 67sub
TX - That was my thought but I called oreilly,autozone and napa all said there was no listing for manual disc.

Here ya go...

http://mpbrakes.com/findmasteracc.htm

jorgensensc · 11-26-2003, 04:45 AM

I did a power brake swap on my '72. It had manual discs when I got it. My manual brakes started going out, so I just did the swap. I love it. I would highly reccommend it. You will have to use a manual brake master if you want to retain your setup. The way the pushrod enters the master is different between the 2. I suggest you do the swap. You can get the setup pretty cheap used. Just be sure and test the booster with a vaccuum. If you have a wild cam you will have a vaccuum problem, but there are ways around that, like late model s-10 electric vaccuum pumps.

67sub · 11-26-2003, 03:49 PM

My cam is not wild by my standards but is by some peoples. It is a Comp with 274/286 duration (230/236 @.050), 487/490 lift, 110 lobe seperation, and 106 centerline. Comp shows this cam should have 11"Hg @ 800rpm and 14" at 1000 rpm, but we ran one in a friends truck and had problems with power brakes.
There is also a major funding issue right now so I was going to try and do the swap ultra cheap but as usual looks like I need to gather up some cash and make sure the parts are right. Thanks everyone for the input and keep it coming if you have any more.
- Curtis

11-25-2003, 03:49 PM	#1
67sub Registered User Join Date: Aug 2003 Location: D/FW TX Posts: 430	Manual Disc Brake ?????? I am converting to 5 lug front disc brakes and remember seeing a thread about which master cylinders are usable. I will not have power brakes, but I am thinking that you can use a power master cylinder. Can anyone offer any tips or advice on this ?What will and what will not work? Thanks for any help - Curtis __________________ 2004 Kawasaki KLR Always looking for a cheap driver

11-25-2003, 04:12 PM	#2
krue Designated A-hole! Join Date: Mar 2003 Location: South Mississippi Posts: 36,450	It's not that hard to put a booster on there and have the best of everything (except maybe rear discs). I would think you would need power to take advantage of the disc brakes. __________________ "If it ain't broke, fix it 'til it is!" Being stupid ain't illegal. We're Still Debt Free Except for the House!!! www.daveramsey.com 70 GMC SWB Stepside project "Green Booger" soon to be 6.0l/4l80e 93 S-10 "Poppaw's Truck"

11-25-2003, 04:37 PM	#3
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Curtis, plenty of the 71-72 trucks came with manual disc brakes. My 72 did. Just buy a non power master cylinder. O reilley has them for under 20 bucks __________________ I'm on the Instagram- @Gearhead_Kevin

11-25-2003, 05:10 PM	#4
67sub Registered User Join Date: Aug 2003 Location: D/FW TX Posts: 430	TX - That was my thought but I called oreilly,autozone and napa all said there was no listing for manual disc. Probably will get what they list and try it anyway. The other question I have is proportion valve. Anybody sell them cheap? yahoo at oreilly said federal regulations would not let aftermarket manufacturers sell them because safety concerns Also will the pushrod into the master cylinder that I currently have work? Thanks for your help. __________________ 2004 Kawasaki KLR Always looking for a cheap driver Last edited by 67sub; 11-25-2003 at 05:20 PM.

11-25-2003, 11:22 PM	#6
dinnut Registered User Join Date: Apr 2003 Location: missouri city, tx Posts: 4,486	most 71-72s didnt have the power booster and like all the 1/2 tons have front discs __________________ 70 longbed 496/th400/Ford 9"

11-25-2003, 11:06 PM	#5
jimfulco Registered User Join Date: May 2003 Location: Shreveport LA Posts: 3,170	Tell them to get out the book & look it up, or go to a real parts place.

11-25-2003, 11:38 PM	#7
FRENCHBLUE72 PROJECT 7DEUCE Join Date: Dec 2002 Location: GRANTS PASS OR Posts: 21,604	No booster's??? I have never seen a 71-72 with out the power booster. Add on's maybe, I doubt it. __________________ GO BIG GREEN GO DUCKS MEMBER #6377 72 k-5 daily driver 6'' lift 35'' 350-350-205 slowly getting rust free. Project "7DEUCE" check out my build http://67-72chevytrucks.com/vboard/s...d.php?t=267665 Tim Powell..R.I.P EastSideLowlife..... R.I.P..

11-25-2003, 11:41 PM	#8
krue Designated A-hole! Join Date: Mar 2003 Location: South Mississippi Posts: 36,450	The point I was trying to make is why not use the booster, you can get the stuff you need for $50 or so and it only takes an hour or so to install, especially if you are going to take the master cylinder off anyways. __________________ "If it ain't broke, fix it 'til it is!" Being stupid ain't illegal. We're Still Debt Free Except for the House!!! www.daveramsey.com 70 GMC SWB Stepside project "Green Booger" soon to be 6.0l/4l80e 93 S-10 "Poppaw's Truck"

11-25-2003, 11:50 PM	#9
FRENCHBLUE72 PROJECT 7DEUCE Join Date: Dec 2002 Location: GRANTS PASS OR Posts: 21,604	I agree with krue if you do not have a booster then add one when you have everything apart,brake's are very important ... __________________ GO BIG GREEN GO DUCKS MEMBER #6377 72 k-5 daily driver 6'' lift 35'' 350-350-205 slowly getting rust free. Project "7DEUCE" check out my build http://67-72chevytrucks.com/vboard/s...d.php?t=267665 Tim Powell..R.I.P EastSideLowlife..... R.I.P..

11-26-2003, 01:25 AM	#10
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Boosters are not really needed..just nice to have IMO. And if you have a wild cam...or plan on one sometime, then the booster can be a real pain in the dana. I had power brakes on the first longhorn and my cam made so little vacume that even an additional vacume canister only let me hit the brakes about 3 or 4 times before the pedal got hard. That'll scare the crap outa you in bumper to bumper rush hr grid lock. Don't know about teh disc set up, but the drum brakes has the same master power or non power. An adjustable prop valve can be had through any performance catalog. Much better than a stock one since it is adjustable. Once you start playing with bigger tires in back it'll throw the stock parameters out the window.

11-26-2003, 01:28 AM	#11
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,950	do not get a master for power disk and use it without a booster you will not be able to push the pedal and stop the truck. you have to use a non power master cylinder if your not using a booster __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

11-26-2003, 04:45 AM	#14
jorgensensc Registered User Join Date: Jul 2003 Location: Cypress, Tx Posts: 4,005	I did a power brake swap on my '72. It had manual discs when I got it. My manual brakes started going out, so I just did the swap. I love it. I would highly reccommend it. You will have to use a manual brake master if you want to retain your setup. The way the pushrod enters the master is different between the 2. I suggest you do the swap. You can get the setup pretty cheap used. Just be sure and test the booster with a vaccuum. If you have a wild cam you will have a vaccuum problem, but there are ways around that, like late model s-10 electric vaccuum pumps. __________________ 1972 C20 Suburban- Big Blue Betty '56 Chevy Bel Air Sedan- Frame up Restoration -What would you attempt to achieve if you knew you could not fail?- -I Refuse To Tiptoe Through Life, Only To Arrive Safely At Death's Door- R.I.P. EAST SIDE LOW LIFE

11-26-2003, 03:49 PM	#15
67sub Registered User Join Date: Aug 2003 Location: D/FW TX Posts: 430	My cam is not wild by my standards but is by some peoples. It is a Comp with 274/286 duration (230/236 @.050), 487/490 lift, 110 lobe seperation, and 106 centerline. Comp shows this cam should have 11"Hg @ 800rpm and 14" at 1000 rpm, but we ran one in a friends truck and had problems with power brakes. There is also a major funding issue right now so I was going to try and do the swap ultra cheap but as usual looks like I need to gather up some cash and make sure the parts are right. Thanks everyone for the input and keep it coming if you have any more. - Curtis __________________ 2004 Kawasaki KLR Always looking for a cheap driver

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