Need master cylinder part number/recommend

[4mulas]

Who has a descent master for manual disc on the front, & drum on the rear. Going on a 69 b body.

Or, if looking up and ordering my own what car would I use as an example?

Thanks!

 

[Xp29h]

260-13375-p is the wilwood part number I used. However, I have disc all around, so I’m not sure. I bet they could tell you.

It’s a manual master with larger piston size.

 

[lilcuda]

Who has a descent master for manual disc on the front, & drum on the rear. Going on a 69 b body.

Or, if looking up and ordering my own what car would I use as an example?

Thanks!

If you don't care about it looking original, Dr Diff has what you need.
https://www.doctordiff.com/aluminum-master-cylinder-kit.html

 

[4mulas]

Okay, I’m looking at doctor diff stuff, and those have to be off the shelf 2 hole masters

Does anyone know which 2 hole masters work for that application?

Thanks!

 

[RJRENTON]

Out of curiosity, a 69 B body with front discs and rear drums had a EITHER a Bendix single diaphragm booster or Midland Ross booster. Same equipment when used with drum brakes all around. A lot also depended on the engine/trans options. I don't believe you could get front discs and rear drums WITHOUT a booster. The master cylinder bore size must be matched to the disc/drum or drum/drum combination to achieve uniform pressure/volume balance to prevent wheel lock ip under hard breaking conditions. If fitting after market components, pay attention to the under dash brake pedal travel, pivot points, push rod length, and a fire wall reinforcing plate and hardware. For after market considerations, its up to the individual's needs or desires and affordability. Do your own do dilligance. Just my opinion of course.
BOB RENTON

 

[4mulas]

Out of curiosity, a 69 B body with front discs and rear drums had a EITHER a Bendix single diaphragm booster or Midland Ross booster. Same equipment when used with drum brakes all around. A lot also depended on the engine/trans options. I don't believe you could get front discs and rear drums WITHOUT a booster. The master cylinder bore size must be matched to the disc/drum or drum/drum combination to achieve uniform pressure/volume balance to prevent wheel lock ip under hard breaking conditions. If fitting after market components, pay attention to the under dash brake pedal travel, pivot points, push rod length, and a fire wall reinforcing plate and hardware. For after market considerations, its up to the individual's needs or desires and affordability. Do your own do dilligance. Just my opinion of course.
BOB RENTON

The 2 bolt master is an OEM master. The bore diameter relates to clamping force. 15/16” bore will give you less pedal feedback, longer stroke but INCREASE braking force. A 1.125” bore gives more harder pedal feedback, shorter stroke, but LESS clamping force.

You can use either, none are wrong, it’s just what you prefer to feel whilst driving.

I’ve spoke with Cass on this and he confirms just that. I’ll probably just order off him, but was hoping to find which one it was exactly as I can order parts locally at great discounts to list through my friends shop.

 

[RJRENTON]

The 2 bolt master is an OEM master. The bore diameter relates to clamping force. 15/16” bore will give you less pedal feedback, longer stroke but INCREASE braking force. A 1.125” bore gives more harder pedal feedback, shorter stroke, but LESS clamping force.

You can use either, none are wrong, it’s just what you prefer to feel whilst driving.

I’ve spoke with Cass on this and he confirms just that. I’ll probably just order off him, but was hoping to find which one it was exactly as I can order parts locally at great discounts to list through my friends shop.

IMO.....B4 committing to your purchase, personally, I would want to see calculations or substantiation of the claim. Is the parts being recommended Mopar parts or generic (read GM or equilivants). What is the bore size of the rear drum brake cylinders? Just remember that the force applied has everything to do with AREA at the applied pedal pressure. Do the area calculations for the master cylinder bore size x pressure developed in relation to the wheel cylinder AREA will give you some idea of how much pedal pressure will be required to expand the shoes. In addition, factor in the same pressure produced as applied to the front disc piston area. Also consider the effect of the "self energizing" effect of the rear drum as the front calipers do not afford this action and will require more pressure to achieve the required "clamping" force. Hence the need for a proportional valve to balance front/rear pressures.
BOB RENTON

 

[4mulas]

IMO.....B4 committing to your purchase, personally, I would want to see calculations or substantiation of the claim. Is the parts being recommended Mopar parts or generic (read GM or equilivants). What is the bore size of the rear drum brake cylinders? Just remember that the force applied has everything to do with AREA at the applied pedal pressure. Do the area calculations for the master cylinder bore size x pressure developed in relation to the wheel cylinder AREA will give you some idea of how much pedal pressure will be required to expand the shoes. In addition, factor in the same pressure produced as applied to the front disc piston area. Also consider the effect of the "self energizing" effect of the rear drum as the front calipers do not afford this action and will require more pressure to achieve the required "clamping" force. Hence the need for a proportional valve to balance front/rear pressures.
BOB RENTON

I Don’t think we’re talking about the same thing but thanks. Doing a 2 hole master with 15/16 bore is a common upgrade. I’m not making the auto parts here, just looking to do a brake job...

 

[RJRENTON]

I Don’t think we’re talking about the same thing but thanks. Doing a 2 hole master with 15/16 bore is a common upgrade. I’m not making the auto parts here, just looking to do a brake job...

It has everything to do with what is being supplied. Do your homework to see if what is being proposed will do what you need (to stop the car safely...every time) and at a price you can afford and what are your alternatives if it does not. The "2 hole master cylinder with a 15/16" bore size is a common up grade" to what? Just be careful wiith your sizing and selection. Just because someone recommended a supplier does not guarantee a perfect solution....to your situation.....CAVIET EMPTOR.
BOB RENTON

 

[4mulas]

The aluminum 2 bolt master with plastic reservoir which has screw on caps is a common performance upgrade to using a crappy leaky cast iron A body 1.032 bore master, which will ultimately leak, rust, and look like crap.

I am converting from drum to disc and have to change the master to get rid of the residual pressure valve. I’m not having random ideas and parts thrust upon me by recommendation of others and do know what I’m doing and what I want. What I’m looking for is an off the shelf 15/16” bore ALUMINUM 2 bolt master with the large plastic not angled reservoir. Someone must know the part number....

Thanks!

Many of these conversions have been done, I have 2 friends who have also done it and their cars with the 15/16” bore masters perform better than the oem set up.

 

[RJRENTON]

The aluminum 2 bolt master with plastic reservoir which has screw on caps is a common performance upgrade to using a crappy leaky cast iron A body 1.032 bore master, which will ultimately leak, rust, and look like crap.

I am converting from drum to disc and have to change the master to get rid of the residual pressure valve. I’m not having random ideas and parts thrust upon me by recommendation of others and do know what I’m doing and what I want. What I’m looking for is an off the shelf 15/16” bore ALUMINUM 2 bolt master with the large plastic not angled reservoir. Someone must know the part number....

Thanks!

Many of these conversions have been done, I have 2 friends who have also done it and their cars with the 15/16” bore masters perform better than the oem set up.

I wish you well with your project.....perhaps you should consider using Dot 5 brake fluid when refilling your system after all your changes. Dot 5 fluid is a silicon based material and is NON HYDROSCOPIC, means it will not absorb moisture, and moisture which will cause corrosion of the fluid handling components...even aluminum. I've used Dot 5 fluid in my numbers matching 70 GTX RS23V0A****** for over 10 years without problems.
BOB RENTON

 

[4mulas]

I wish you well with your project.....perhaps you should consider using Dot 5 brake fluid when refilling your system after all your changes. Dot 5 fluid is a silicon based material and is NON HYDROSCOPIC, means it will not absorb moisture,
BOB RENTON

I probably will.

If you haven’t changed it out yet, you may want to consider doing so, yes it doesn’t absorb water, so moisture can pool so to speak in the system and still cause havoc hydraulically and with corrosion.

I like it purely because it doesn’t eat paint.

 

[4mulas]

If you don't care about it looking original, Dr Diff has what you need.
https://www.doctordiff.com/aluminum-master-cylinder-kit.html

After searching around and contemplating I called Cass and ordered up!
Went with the 15/16 bore aluminum conversion unit, and also got calipers, p valve and some hoses too.
Thanks for the recommendation