AD Manual Brake Conversion on a 1980 El Camino

M

malibudave

Apprentice
Mar 12, 2010
74
48
18
Houston, TX
#31
I am done testing the manual brake setup with a stock, aluminum, rebuilt, 24mm bore, 1980 El Camino master cylinder. With only this change, I got back the brake fluid pressure that I lost when I upgraded to the Wilwood 2.75” metric calipers using the 7/8” bore master cylinder. I bench bleed the master cylinder installed it in place of the 7/8” bore master cylinder, bled the line at the master cylinder, and then bled the car at all four wheels.

On the test drive, using the 24mm master, I did a few hard stops from about 30 mph. I was rewarded with both rear wheels locking up, but the front braking system felt as if it still wasn’t grabbing. After the testing, I jacked the front of the car and removed the wheels and I unbolted the calipers so I can take a look at the pads. I suppose during my very first manual brake test, I did not bed the brakes in properly and I glazed the brake pads over. I do not know why I did not notice this when I put on the Wilwood calipers other than not recognizing what glazed pads look like. The glazing most likely happened because I had a large master cylinder and small calipers on my first manual brake test and, at the time, I wasn’t getting enough pressure to the pads to do accomplish correct bedding. The moral of the story is to bed your pads properly.

Good news is that I found out what the issue is with the front brakes not grabbing. Bad news is that I didn’t deglaze my pads and retest. I didn’t deglaze the pads I originally used because went ahead and upgraded to a Wilwood Polymatrix A brake pad.

I went to the Wilwood PolymatrixA pad because of its good, cold clamping properties and, before I realized about the glazing pads, I had thought this would help with front brakes. **As a warning from Wilwood to any one using these pads, Wilwood considers these race pads**. These are aggressive pads and will most likely wear the front rotors prematurely and are intended for race use only. These pads have almost twice the friction coefficient as a “stock” type pad. I am using this aggressive pad because the front rotors are small, the brake pads are small, the front calipers are a floating design, and the car is now has manual brakes. These pads are also a wallet buster at $150 a set.

The braking test with these pads where a noticeable night a day difference. I felt very comfortable and confident while driving and stopping. On hard stops, the nose of the car would “dive” down and the rear wheels still locked up. Only time will tell if these front pads are good for everyday use with this manual brake setup.

If your car is a daily driver and not a drag car, you most likely do not need to change out to larger wheel cylinders on the rear drum brakes like I did. The original stock 3/4” bore wheel cylinders versus the larger 7/8” bore wheel cylinders should reduce rear lock up on hard braking.

For a drag racer with large, wide, sticky tires on the back, the larger 7/8” bore wheel cylinder may be better to keep the rear tires from spinning when your holding the car on the line with just the brakes. An aggressive front pad may also be needed to hold the car on the line (contact one of the major brake pad manufactures for suggestions).

From my experience, to do a manual brake system on a g-body or s-10, some or all of the brake components will have to be replaced. You cannot just remove the vacuum booster and bolt the master cylinder to the firewall and expect your braking to function well. It is a system approach.

Do you need an oversized caliper? In my opinion, no you do not.

Do you need to change out the front calipers? In my opinion, yes you do. Why? Because the stock calipers may or may not be a LOW DRAG design which requires a step bore master cylinder. How do you know that you have LOW DRAG calipers? You actually cannot physically tell, so its best to buy aftermarket calipers to cut down on variables that may cause trouble with your braking system.

Do I recommend rebuilt front calipers from the auto parts store? No. See above.

Do you need to change out the master cylinder? In my opinion, most likely you will need to. Why? It depends on what you are starting with. If you have a GM g-body vehicle that was built from 1978 to 1980, you have a strait bore, 24mm bore master cylinder from the factory and you can just upgrade to Wilwood 2.75” bore calipers if you master cylinder is in good working order. If you have a vehicle built from 1981 through 2003 you most likely have a step bore master cylinder. These master cylinders are too large for almost all manual brake conversions on a g-body or s-10. Now a choice has to be made. How much money do you want to spend on aftermarket front calipers? Cheapest ones that I have found are around $45 each with a stock size bore from U.S. Brakes. You will then need a 7/8” bore master cylinder to match to these front calipers. For a g-body car you can go with a new or rebuilt, stock replacement from a 1978 to 1980 g-body manual brake master cylinder. For an S-10, the only option I have found that readily bolts to the firewall and to the brake lines is a Wilwood 7/8” bore master cylinder. If upgrading to the Wilwood 2.75” bore calipers, you will need a 24mm master cylinder. The g-body options are a new or built stock power brake unit from a 1978 to 1980 g-body car. New ones will be cast iron. Most rebuilt ones will be cast iron. For some reason, the 1980 model years came in aluminum and these can be bought rebuilt (like I have installed in the latest test). For a s-10, you can use a stock replacement manual brake master cylinder from a 1982 to 1992 s-10 truck with manual brakes. These are step bore master cylinders with a primary bore of 1-1/4” and a secondary bore of 24mm. I do not recommend these master cylinders because they are hard to bleed and have a bypass valve that can fail. The other options are a 24mm Wilwood master cylinder and a 1990s 24mm Dodge Dakota master cylinder. Only issue with the Dakota master is the rear brake port is 9/16-20 instead of 9/16-18. I have found no adapter for this conversion yet.

Do I recommend step bore master cylinders? No, because they are generally too large for a stock size front caliper, they are hard to bleed, and they have a bypass valve that may fail. These three issues can be remedied by using a correct size strait bore master cylinder. A 7/8” bore master cylinder for stock bore, aftermarket calipers and 24mm bore master cylinder for a Wilwood 2.75” bore calipers.

Do I recommend other oversized front calipers other than the Wilwood 2.75” front calipers? No, because their piston size in these oversized calipers are not much larger than stock. The Wilwood caliper, visually, looks to be engineered better.

Do I recommend stock size calipers? U.S. Brake is the only caliper, of the aftermarket cast iron replacements I know, that is not a low drag caliper. There may be other aftermarket, “metric” calipers, but I cannot confirm if they are low drag or not. The U.S. Brake calipers are based on a stock casting. The other alternative is a stock, replacement aluminum, “metric” caliper from Wilwood. I have not used or viewed one of these calipers, but from engineering of the 2.75” bore and 2.00” bore calipers I have viewed, I suspect they should be just as well engineered and lighter.

Do I recommend larger wheel cylinders? If the car is street driven, most likely no. If drag raced, most likely yes to keep the rear tires from spinning when doing a brake stand

Do I recommend braided stainless steel flex lines? Yes, for the reduced ballooning and better pedal feel, but is not necessary.
 
M

malibudave

Apprentice
Mar 12, 2010
74
48
18
Houston, TX
#32
Here is a list of strait bore master cylinders that will bolt up to a G-body’s angled firewall when using a flat, manual brake adapter plate. This is a list from smallest to largest.

21mm (0.826”) bore 1993 Dodge Shadow master cylinder (other years and models may work)
• Requires adapters to mate master cylinder outlet to stock lines. The adapter Part number is MC-SF at http://www.classicperform.com.
• Mounting holes spaced 3.25” versus GM master cylinder’s 3.375”.
• Hard to find.
• Light in weight.
• Advertised as 21mm, but may be delivered in 7/8” or 24mm bores. Measure bore size before you buy. Rebuilt/Used ones will have a “1” cast into the front of the aluminium body under the reservoir.
• Can buy new or used. New ones are fairly cheap to purchase.
• Aluminium body – new, used, or rebuilt.
• Large reservoir can hold enough fluid for rear disc brakes.

7/8” (0.875”) bore 1978-1980 GM G-body manual brake master cylinders.
• Can buy new or used. Rebuilt are fairly cheap. New are fairly expensive.
• Reservoir too small for rear disc brakes. The reservoir from 1979 Buick Riviera with four wheel disc brakes can be retrofitted to this master cylinder.
• Advertised as manual brake units, but may be delivered as a 24mm, vacuum power boosted unit. Measure bore size before you buy.
• Bolt in.
• Cast iron body – new, used, or rebuilt. (no aluminium)

7/8” (0.875”) bore 1993 Dodge Shadow master cylinder (other years and models may work)
• Requires adapters to mate master cylinder outlet to stock lines. The adapter Part number is MC-SF at http://www.classicperform.com.
• Mounting holes spaced 3.25” versus GM master cylinder’s 3.375”.
• Easier to find.
• Light in weight.
• Advertised as 7/8”, but may be delivered in a 24mm bore. Measure bore size before you buy.
• Rebuilt/Used ones will have an “8” cast into the front of the aluminium body under the reservoir.
• Can buy new or used. New ones are fairly cheap to purchase.
• Aluminium body – new, used, or rebuilt.
• Large reservoir can hold enough fluid for rear disc brakes.

24mm (0.944”) bore 1978-1980 GM G-body power brake master cylinders.
• Can buy new or used. Used are fairly cheap. New are fairly expensive.
• Reservoir too small for rear disc brakes. The reservoir from 1979 Buick Riviera with four wheel disc brakes can be retrofitted to this master cylinder.
• Bolt in.
• Come in cast iron and aluminium. 1978-1979 are cast iron. 1980 is aluminium (some models i.e. El Camino).
• New master cylinders will most likely be cast iron regardless of year.
• Rebuilt units come in cast iron and aluminium (1980 – some models).

24mm (0.944”) bore 1993 Dodge Shadow master cylinder (other years and models may work)
• Requires adapters to mate master cylinder outlet to stock lines. The adapter Part number is MC-SF at http://www.classicperform.com.
• Mounting holes spaced 3.25” versus GM master cylinder’s 3.375”.
• Easiest to find.
• Light in weight.
• Advertised as 24mm, but may be delivered in a 7/8” bore. Measure bore size before you buy.
• Rebuilt/Used ones will have a “4” cast into the front of the aluminium body under the reservoir.
• Can buy new or used. New ones are fairly cheap to purchase.
• Aluminium body – new, used, or rebuilt.
• Large reservoir can hold enough fluid for rear disc brakes.

24mm (0.944”) bore 1993 Dodge Dakota master cylinder (other years and models may work)
• Rear brake line outlet is 9/16-20 versus GM rear brake line fitting of 9/16-18. The fitting for GM brake line may be used to “rethread” the master cylinder’s outlet.
• Front brake lines bolt up.
• Mounting holes spaced 3.25” versus GM master cylinder’s 3.375”.
• Can buy new or used. New ones are fairly cheap to purchase.
• Aluminium body – new, used, or rebuilt.
• Large reservoir can hold enough fluid for rear disc brakes.
• Reservoir not angled like above Dodge and GM master cylinders.

1.0” bore 1979 Buick Riviera with 4 Wheel Disc Brakes.
• Can buy new or used. Used are fairly cheap. New are fairly expensive.
• Reservoir is made for rear disc brakes.
• Bolt in.
• Come in cast iron and aluminium.
• New master cylinders will most likely be cast iron.
• Rebuilt units usually come in aluminium.

1 1/32” (1.03”) bore 1985 Dodge Diplomat master cylinder (other years and models may work)
• Rear brake line outlet is 9/16-20 versus GM rear brake line fitting of 9/16-18. Fitting for GM brake line may be used to “rethread” the master cylinder’s outlet.
• Front brake lines bolt up.
• Mounting holes spaced 3.25” versus GM master cylinder’s 3.375”.
• Can buy new or used. New ones are fairly cheap to purchase.
• Aluminium body – new, used, or rebuilt.
• Large reservoir can hold enough fluid for rear disc brakes.
• Reservoir not angled like above Dodge and GM master cylinders.

1 1/8” (1.125”) bore 1985 Dodge Ram master cylinder (other years and models may work)
• Rear brake line outlet is 9/16-20 versus GM rear brake line fitting of 9/16-18. Fitting for GM brake line may be used to “rethread” the master cylinder’s outlet.
• Front brake lines bolt up.
• Mounting holes spaced 3.25” versus GM master cylinder’s 3.375”.
• Can buy new or used. New ones are fairly cheap to purchase.
• Aluminium body – new, used, or rebuilt.
• Large reservoir can hold enough fluid for rear disc brakes.
• Reservoir not angled like above Dodge and GM master cylinders.
 
pontiacgp

pontiacgp

Canadian Prime Minister
Mar 31, 2006
24,191
9,385
113
Kitchener, Ontario
#33
thanks for posting all that info...it's very helpful.... :)
 
M

malibudave

Apprentice
Mar 12, 2010
74
48
18
Houston, TX
#34
One of the main problems that arise when converting to manual brakes using a 7/8" bore master cylinder is LOW drag calipers.

LOW drag calipers require a step bore (quick take up) master cylinder. In my opinion they are too large to operate smaller 2.50" bore calipers with sufficient pressure, they are harder to bleed, and they have a 100lb residual valve that can fail. My opinion also is to change out to new (NOT rebuilt) calipers to make sure you do not get a set of LOW drag calipers.

To learn a little bit about new stock size calipers, I just purchased a set of left and right AFCO 2.5" bore metric calipers that are a bolt in, stock, replacement caliper for g-bodies, S10s, and most 3rd gen f-bodies. I removed the stainless steel piston and square piston seal to make sure it was not a LOW drag caliper.

SPECS:
MFG. Part #: 7241-9003 RH and 7241-9004 LH
Centerline of Holes: 5.50
Caliper Pistons: Single Piston Diameter: 2.50
Inlet fitting: 10mm-1.5 Material Type:
Steel Finish: Natural
Sold in Quantity: Each

Description:
The 2 1/2" bore steel GM metric caliper is designed to be a used as a stock replacement caliper. The caliper features a stock appearing remanufactured castings, remanufactured grounded 2 1/2" stainless steel piston, and low drag seals (see below) . Each caliper is assembled and pressure tested.

LOW DRAG SEALS
Though the description says "low drag seals", the seals are square with no noticable taper.
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proxy.php?image=http%3A%2F%2Fi724.photobucket.com%2Falbums%2Fww247%2Fmalibudave%2FCaliperPistonSeal2.jpg&hash=f5faa6c6e4dc9e2a516a543a253291b0


The seal-groove in the bore of the caliper are also square with no noticable taper.
proxy.php?image=http%3A%2F%2Fi724.photobucket.com%2Falbums%2Fww247%2Fmalibudave%2FCaliperHousingSealGroove3.jpg&hash=af26c214dcee627a6d3fc7262a286ae6


When the seal is installed, it barely clears the top of the bore, and because of this, the piston to bore clearance, it seams, to have fairly tight tolerances.

The small end of the piston is what contacts the back of the brake pad. It measures 2.38".
The large end of the piston is what is inside the bore of the caliper. It measures 2.50"
proxy.php?image=http%3A%2F%2Fi724.photobucket.com%2Falbums%2Fww247%2Fmalibudave%2FCaliperPiston2.jpg&hash=99f98b4fc4afc7e9f0b3a4bbc387c6e6


Inside of piston cup, facing the brake pad.
proxy.php?image=http%3A%2F%2Fi724.photobucket.com%2Falbums%2Fww247%2Fmalibudave%2FCaliperPiston3.jpg&hash=ce4cbbb0fc4cb24d5704797892da7b0a


Backside of piston that is installed inside the caliper bore.
proxy.php?image=http%3A%2F%2Fi724.photobucket.com%2Falbums%2Fww247%2Fmalibudave%2FCaliperPiston1.jpg&hash=1ce3205b65abd27d59276ec7249948e4


I have bought these same exact part numbers a few years back and these new ones are a different casting with, what looks to be, a stainless steel piston. These calipers DO NOT come with pads, but they come with slider pins and slider pin bushings. At this time, they are around $40, and seem to be an improvement over the previous design.

Bottom line is that these should be a good stock replacement, NON low drag, brake caliper that will work with both strait bore master cylinders and step bore (quick take up) master cylinders.
 
M

malibudave

Apprentice
Mar 12, 2010
74
48
18
Houston, TX
#35
Caliper Update:

I have found a good NON low drag (normal) bolt in replacement brake calipers for stock front brake systems. These brake calipers can be used with strait bore (normal) master cylinders and step bore master cylinders.

It is under the Centric Brand. They are about $33 plus shipping at rockauto.com.

Part number are:
14162066
14162065

AFCO has a brand new replacement brake calipers. They are about $49.99 plus shipping. $100 order are free shipping at Summit Racing, Jegs, and Speedway Motors. These should be NON low drag.

The part numbers are:
6635003
6635004
 
Last edited:
M

malibudave

Apprentice
Mar 12, 2010
74
48
18
Houston, TX
#36
Manual brake installation with adapter plate painted satin black to match firewall better.

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M

malibudave

Apprentice
Mar 12, 2010
74
48
18
Houston, TX
#37
Below is an analysis using the Brake Torque Calculator found on Pro-Touring.com. This calculator will give you an idea of what brake torque is for a certain front and rear setups. I am just going to show the changes from the stock front g-body brake system and compare them to a Blazer dual piston brake swap, a stock LS1 Camaro brake swap, a LS1 Camaro brake swap with Corvette calipers

Page 7, Post #140

http://www.pro-touring.com/threads/...featuring-Ron-Sutton-and-Tobin-of-KORE3/page7
This entire post is a really good read if you are interested about brakes.


Here are the inputs that are the same for ALL different types of brake systems shown below.
• 6 to 1 pedal ratio
• 26” tall tire
• 100 ft/lb pedal pressure
• Manual Brakes – NO POWER ASSIST
• Pad Coefficient of Friction - .45
• Use of stock type (tandem) master cylinder

____________________________________________________
Stock G-body/S10/3rd Generation F-body Front Brake System
• Rotor Diameter – 10.5”
• 7/8” Bore Master Cylinder Area - .601 sq-in
• Line Pressure – 998 psi
• Front Caliper Piston Area – 4.909 sq-in
• Front Clamping Pressure – 4899 pounds
Front Rotor Torque – 964 ft/lb
• Tire Forces – 890 lb
____________________________________________________
Stock LS1 Camaro/Firebird Front Brake System
• Rotor Diameter – 12”
• 7/8” Bore Master Cylinder Area - .601 sq-in
• Line Pressure – 998 psi
• Front Caliper Piston Area – 4.931 sq-in
• Front Clamping Pressure – 4921 pounds
Front Rotor Torque – 1107 ft/lb
• Tire Forces – 1022 lb
____________________________________________________
Stock LS1 Camaro/Firebird Front Brake System with Corvette Calipers with 7/8” bore master cylinder
• Rotor Diameter – 12”
• 7/8” Bore Master Cylinder Area - .601 sq-in
• Line Pressure – 998 psi
• Front Caliper Piston Area – 3.994 sq-in
• Front Clamping Pressure – 3986 pounds
Front Rotor Torque – 897 ft/lb
• Tire Forces – 828 lb

Stock LS1 Camaro/Firebird Front Brake System with Corvette Calipers with 21mm bore master cylinder
• Rotor Diameter – 12”
• 21mm Bore Master Cylinder Area - .537 sq-in
• Line Pressure – 1117 psi
• Front Caliper Piston Area – 3.994 sq-in
• Front Clamping Pressure – 4461 pounds
Front Rotor Torque – 1004 ft/lb
• Tire Forces – 927 lb

____________________________________________________
Stock Blazer Twin Piston Front Brake System
NOTE: The Blazer twin piston front calipers have a piston area too large to run a .875” bore master cylinder. These calculations are using a 24mm bore master cylinder.
• Rotor Diameter – 10.75”
• 24mm Bore Master Cylinder Area - .701 sq-in
• Line Pressure – 856 psi
• Front Caliper Piston Area – 5.152 sq-in
• Front Clamping Pressure – 4410 pounds
Front Rotor Torque – 889 ft/lb
• Tire Forces – 821 lb

Stock Blazer Twin Piston Front Brake System
NOTE: The Blazer twin piston front calipers have a piston area too large to run a .875” bore master cylinder. But to show the differences between the systems, these calculations are using a .875” bore master cylinder.
• Rotor Diameter – 10.75”
• 7/8” Bore Master Cylinder Area - .601 sq-in
• Line Pressure – 998 psi
• Front Caliper Piston Area – 5.152 sq-in
• Front Clamping Pressure – 5142 pounds
Front Rotor Torque – 1036 ft/lb
• Tire Forces – 956 lb


Rating from best to worst:
1. LS1 Camaro / Firebird stock front brakes with 7/8" bore master cylinder.
2. Blazer Twin piston stock front brakes with 7/8” bore master cylinder. NOTE: This setup will not work with a 7/8” bore master cylinder.
3. LS1 Camaro / Firebird front brakes with Corvette brake calipers and a 21mm bore master cylinder. NOTE: A 21mm master cylinders are fairly rare and hard to find.
4. Stock g-body/S10/3rd Generation F-body stock front brake system with 7/8" bore master cylinder.
5. LS1 Camaro / Firebird front brakes with Corvette brake calipers and a 7/8” bore master cylinder.
6. Blazer Twin piston stock front brakes with 24mm bore master cylinder.
 
Last edited:
Garrett1982

Garrett1982

G-Body Guru
May 18, 2014
582
86
28
Uniontown, Pa
#38
Below is an analysis using the Brake Torque Calculator found on Pro-Touring.com. This calculator will give you an idea of what brake torque is for a certain front and rear setups. I am just going to show the changes from the stock front g-body brake system and compare them to a Blazer dual piston brake swap, a stock LS1 Camaro brake swap, a LS1 Camaro brake swap with Corvette calipers

Page 7, Post #140

http://www.pro-touring.com/threads/...featuring-Ron-Sutton-and-Tobin-of-KORE3/page7
This entire post is a really good read if you are interested about brakes.


Here are the inputs that are the same for ALL different types of brake systems shown below.
• 6 to 1 pedal ratio
• 26” tall tire
• 100 ft/lb pedal pressure
• Manual Brakes – NO POWER ASSIST
• Pad Coefficient of Friction - .45
• Use of stock type (tandem) master cylinder

____________________________________________________
Stock G-body/S10/3rd Generation F-body Front Brake System
• Rotor Diameter – 10.5”
• 7/8” Bore Master Cylinder Area - .601 sq-in
• Line Pressure – 998 psi
• Front Caliper Piston Area – 4.909 sq-in
• Front Clamping Pressure – 4899 pounds
Front Rotor Torque – 964 ft/lb
• Tire Forces – 890 lb
____________________________________________________
Stock LS1 Camaro/Firebird Front Brake System
• Rotor Diameter – 12”
• 7/8” Bore Master Cylinder Area - .601 sq-in
• Line Pressure – 998 psi
• Front Caliper Piston Area – 4.931 sq-in
• Front Clamping Pressure – 4921 pounds
Front Rotor Torque – 1107 ft/lb
• Tire Forces – 1022 lb
____________________________________________________
Stock LS1 Camaro/Firebird Front Brake System with Corvette Calipers with 7/8” bore master cylinder
• Rotor Diameter – 12”
• 7/8” Bore Master Cylinder Area - .601 sq-in
• Line Pressure – 998 psi
• Front Caliper Piston Area – 3.994 sq-in
• Front Clamping Pressure – 3986 pounds
Front Rotor Torque – 897 ft/lb
• Tire Forces – 828 lb

Stock LS1 Camaro/Firebird Front Brake System with Corvette Calipers with 21mm bore master cylinder
• Rotor Diameter – 12”
• 21mm Bore Master Cylinder Area - .537 sq-in
• Line Pressure – 1117 psi
• Front Caliper Piston Area – 3.994 sq-in
• Front Clamping Pressure – 4461 pounds
Front Rotor Torque – 1004 ft/lb
• Tire Forces – 927 lb

____________________________________________________
Stock Blazer Twin Piston Front Brake System
NOTE: The Blazer twin piston front calipers have a piston area too large to run a .875” bore master cylinder. These calculations are using a 24mm bore master cylinder.
• Rotor Diameter – 10.75”
• 24mm Bore Master Cylinder Area - .701 sq-in
• Line Pressure – 856 psi
• Front Caliper Piston Area – 5.152 sq-in
• Front Clamping Pressure – 4410 pounds
Front Rotor Torque – 889 ft/lb
• Tire Forces – 821 lb

Stock Blazer Twin Piston Front Brake System
NOTE: The Blazer twin piston front calipers have a piston area too large to run a .875” bore master cylinder. But to show the differences between the systems, these calculations are using a .875” bore master cylinder.
• Rotor Diameter – 10.75”
• 7/8” Bore Master Cylinder Area - .601 sq-in
• Line Pressure – 998 psi
• Front Caliper Piston Area – 5.152 sq-in
• Front Clamping Pressure – 5142 pounds
Front Rotor Torque – 1036 ft/lb
• Tire Forces – 956 lb


Rating from best to worst:
1. LS1 Camaro / Firebird stock front brakes with 7/8" bore master cylinder.
2. Blazer Twin piston stock front brakes with 7/8” bore master cylinder. NOTE: This setup will not work with a 7/8” bore master cylinder.
3. LS1 Camaro / Firebird front brakes with Corvette brake calipers and a 21mm bore master cylinder. NOTE: A 21mm master cylinders are fairly rare and hard to find.
4. Stock g-body/S10/3rd Generation F-body stock front brake system with 7/8" bore master cylinder.
5. LS1 Camaro / Firebird front brakes with Corvette brake calipers and a 7/8” bore master cylinder.
6. Blazer Twin piston stock front brakes with 24mm bore master cylinder.
I bought your kit for my Cutlass a while back. I am still in the process of building the car. When I purchased the kit you said you didn't test the blazer dual piston calipers yet but you recommended the 7/8 bore MC. Thats what I went with. Should I still try it, after your testing, or change to the 24mm?
 
M

manualbrakes.com

Not-quite-so-new-guy
Feb 11, 2016
24
19
3
#39
I bought your kit for my Cutlass a while back. I am still in the process of building the car. When I purchased the kit you said you didn't test the blazer dual piston calipers yet but you recommended the 7/8 bore MC. Thats what I went with. Should I still try it, after your testing, or change to the 24mm?
What brakes are you running on the back?

I had another customer try it with the Blazer brakes and he said he didn't get any pedal, but that was one customer. Please try it with the 7/8" bore master cylinder. If you find it not supplying enough fluid for the Blazer brakes, please let me know and I will swap it out with a 24mm bore master cylinder at no charge.

Either way, please let me know how the swap goes and post up pictures of your progress.
 
Garrett1982

Garrett1982

G-Body Guru
May 18, 2014
582
86
28
Uniontown, Pa
#40
image-jpeg.47657
What brakes are you running on the back?

I had another customer try it with the Blazer brakes and he said he didn't get any pedal, but that was one customer. Please try it with the 7/8" bore master cylinder. If you find it not supplying enough fluid for the Blazer brakes, please let me know and I will swap it out with a 24mm bore master cylinder at no charge.

Either way, please let me know how the swap goes and post up pictures of your progress.
I am going to run the Right Stuff disc conversion for a 9". I am pretty sure it uses GM metric calipers. I didn't purchase it yet. The only thing I need for the blazer upgrade is the calipers.
I have your kit installed already, along with Classic Tube stainless lines and Russell braided flex lines.
Everthing fit great. Easy install.
 

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