Power to Manual Brakes - The 1947 - Present Chevrolet & GMC Truck Message Board Network

redsled87 · 06-02-2012, 10:44 AM

I'm in the process of converting my truck. I know of two guys that took off the power booster and just moved back the master cyl. That's what I'm going to do for now until I put in my new rear. I'm leaning towards putting disc brakes on the new rear so, I don't want to buy a master this year and then, buy another next year. So, my question is, has anyone done this and what, do ai have to do to the pushrod? BTW, the truck is an '87 R10.

cableguy0 · 06-02-2012, 11:57 AM

You really need to use a master cylinder for manual brakes. Using a power brakes master cylinder without the booster is going to hurt your braking performance A LOT. UNhook the vacuum line for your booster and try to drive around. The first time you have to stop in a hurry you will rethink your plans.

**Captainfab** · 06-02-2012, 11:23 PM

I would suggest switching to a manual master cylinder also, for a couple reasons. First, with the manual master cylinders, the pushrod is secured to the back of the piston, much as it is in the back of a booster. Secondly, the manual master connects to the pedal arm up above where the power brake booster attaches. The correst manual msater will have a pushrod the correct length and will attach in the correst location. You may have to get a master for a mid 70's truck to be able to get one for manual brakes. And they aren't all that expensive.

redsled87 · 06-03-2012, 12:20 AM

Well, I talked to a friend that has a junk yard today. He has a manual brake pushrod. I'll have it this coming week. I've decided to buy the right master cyl. We were talking about what Captain Fab said about the deeper bore of a manual cylinder where, the pushrod goes. I have a raybestos brake book and, they list a manual master cyl. for my truck. So, I'm going to order one this coming week.

redsled87 · 06-03-2012, 12:42 PM

Now here is good one. I called a parrts store today. I asked them to measure the back of the master cyl. They did and, its the same measurement as my power one. He did double check the application and part number too. I even looked on the Raybestos wedsite and, its the same. So, I guess I'll go back to my original plan and use the original. The bore diameters are really close.
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BR3W CITY · 06-03-2012, 01:01 PM

Not trying to be a doubter, but I'm not sure I'd trust that. I have manual brakes, and the master WAS different. Fwiw, if you look at RockAuto, they list 2 different part numbers for "w manual brake" and "w/ power or vacuum boosted brakes".

badpontiacs · 06-03-2012, 11:06 PM

I have a manual setup on my truck. When it was wrecked, I got a new body and swapped it over. I kept the manual master from the original frame and installed it on a power booster from the new body. I only had to swap the push rod which was longer but very simple. I mic'd the bores to double check and they were both identical. One frame was a '73 and the body is a '78. I haven't had any troubles with this swap. It stops on a dime and doesnt pull. I too have disc/disc.

stireson87 · 06-15-2015, 04:21 PM

hey captainfab, I have a 72 long bed i am wanting to convert to manual brakes instead of my power, I know i will need a manual style master cylinder. what else will i need to do or get to make the switch over. also would you might know of a brand or one you have used with good results i am wanting in the future to switch over to disk on the rear. Any help would be appreciated sir thanks.

**Captainfab** · 06-16-2015, 02:05 AM

You will also need a manual brakes pushrod. When you convert to 4 wheel discs, a '76 and earlier Corvette master will work with your long pushrod for manual brakes.

Quote:

Originally Posted by stireson87

hey captainfab, I have a 72 long bed i am wanting to convert to manual brakes instead of my power, I know i will need a manual style master cylinder. what else will i need to do or get to make the switch over. also would you might know of a brand or one you have used with good results i am wanting in the future to switch over to disk on the rear. Any help would be appreciated sir thanks.

PhilaTruck · 06-21-2015, 02:34 PM

I used a unit from a Dodge Caravan. Slotted out the top holes and modded the pushrod. Pretty straightforward and cheap for now.

**regan wilson** · 06-22-2015, 08:55 AM

I dont have the Raybestos part number but I use a Corvette manual mc. It would be for a early 70s Vette. New one cost me 37 dollars the other day. With stock front discs I ruined a few front runners driving the stripe. I can look later if yall want it

06-02-2012, 10:44 AM	#1
redsled87 Registered User Join Date: Dec 2011 Location: Lanc Co PA Posts: 226	Power to Manual Brakes I'm in the process of converting my truck. I know of two guys that took off the power booster and just moved back the master cyl. That's what I'm going to do for now until I put in my new rear. I'm leaning towards putting disc brakes on the new rear so, I don't want to buy a master this year and then, buy another next year. So, my question is, has anyone done this and what, do ai have to do to the pushrod? BTW, the truck is an '87 R10. __________________ 1987 R10 Pump Gas 496/TH375 Best 1/4 pass to date 60' 1.49 1/4 10.93 MPH 120

06-02-2012, 11:57 AM	#2
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,950	Re: Power to Manual Brakes You really need to use a master cylinder for manual brakes. Using a power brakes master cylinder without the booster is going to hurt your braking performance A LOT. UNhook the vacuum line for your booster and try to drive around. The first time you have to stop in a hurry you will rethink your plans. __________________ 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.

06-02-2012, 11:23 PM	#3
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,246	Re: Power to Manual Brakes I would suggest switching to a manual master cylinder also, for a couple reasons. First, with the manual master cylinders, the pushrod is secured to the back of the piston, much as it is in the back of a booster. Secondly, the manual master connects to the pedal arm up above where the power brake booster attaches. The correst manual msater will have a pushrod the correct length and will attach in the correst location. You may have to get a master for a mid 70's truck to be able to get one for manual brakes. And they aren't all that expensive. __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

06-03-2012, 12:20 AM	#4
redsled87 Registered User Join Date: Dec 2011 Location: Lanc Co PA Posts: 226	Re: Power to Manual Brakes Well, I talked to a friend that has a junk yard today. He has a manual brake pushrod. I'll have it this coming week. I've decided to buy the right master cyl. We were talking about what Captain Fab said about the deeper bore of a manual cylinder where, the pushrod goes. I have a raybestos brake book and, they list a manual master cyl. for my truck. So, I'm going to order one this coming week. __________________ 1987 R10 Pump Gas 496/TH375 Best 1/4 pass to date 60' 1.49 1/4 10.93 MPH 120

06-03-2012, 12:42 PM	#5
redsled87 Registered User Join Date: Dec 2011 Location: Lanc Co PA Posts: 226	Re: Power to Manual Brakes Now here is good one. I called a parrts store today. I asked them to measure the back of the master cyl. They did and, its the same measurement as my power one. He did double check the application and part number too. I even looked on the Raybestos wedsite and, its the same. So, I guess I'll go back to my original plan and use the original. The bore diameters are really close. Posted via Mobile Device __________________ 1987 R10 Pump Gas 496/TH375 Best 1/4 pass to date 60' 1.49 1/4 10.93 MPH 120

06-03-2012, 01:01 PM	#6
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: Power to Manual Brakes Not trying to be a doubter, but I'm not sure I'd trust that. I have manual brakes, and the master WAS different. Fwiw, if you look at RockAuto, they list 2 different part numbers for "w manual brake" and "w/ power or vacuum boosted brakes". __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

06-03-2012, 11:06 PM	#7
badpontiacs Registered User Join Date: Nov 2011 Location: Valparaiso, Indiana Posts: 195	Re: Power to Manual Brakes I have a manual setup on my truck. When it was wrecked, I got a new body and swapped it over. I kept the manual master from the original frame and installed it on a power booster from the new body. I only had to swap the push rod which was longer but very simple. I mic'd the bores to double check and they were both identical. One frame was a '73 and the body is a '78. I haven't had any troubles with this swap. It stops on a dime and doesnt pull. I too have disc/disc. __________________

06-15-2015, 04:21 PM	#8
stireson87 Registered User Join Date: Apr 2014 Location: springfield mo Posts: 4	Re: Power to Manual Brakes hey captainfab, I have a 72 long bed i am wanting to convert to manual brakes instead of my power, I know i will need a manual style master cylinder. what else will i need to do or get to make the switch over. also would you might know of a brand or one you have used with good results i am wanting in the future to switch over to disk on the rear. Any help would be appreciated sir thanks.

06-21-2015, 02:34 PM	#10
PhilaTruck Right on the line, baby! Join Date: Oct 2003 Location: Phila, PA 19130 Posts: 1,486	Re: Power to Manual Brakes I used a unit from a Dodge Caravan. Slotted out the top holes and modded the pushrod. Pretty straightforward and cheap for now. __________________ 83 GMC 406 th400/3.73 Eaton Truetrac posi, headers, x pipe, & racePros. Tubular control arms, lowering rear springs, caltracs. Still ugly, but getting built right, although slowly Click and scroll down for site vendors! Subscribe here!

06-22-2015, 08:55 AM	#11
regan wilson Senior Member Join Date: Mar 2008 Location: tyler texas Posts: 1,532	Re: Power to Manual Brakes I dont have the Raybestos part number but I use a Corvette manual mc. It would be for a early 70s Vette. New one cost me 37 dollars the other day. With stock front discs I ruined a few front runners driving the stripe. I can look later if yall want it __________________ NHRA Super Street 469C It only runs 10.90 at 156 mph



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