Disc Brake Master Cylinders? Billy Nees Help!

[HandOverFist]

Originally Posted by rallye bob

The bore size on that M/C is only 0.83 in... I think that may be under sized for the OP's needs...

You are likely correct...I just posted the link for philbilly.

[njk53]

Can't remember how it goes, is it the larger the M/C bore the harder the pedal effort or is it the other way around the smaller the bore the harder the pedal effort?

[HandOverFist]

I think it is the latter. We use a 1.032 bore with 4-pistons in the rear and 2-pistons up front.

[Tom keedle]

Originally Posted by HandOverFist

I think it is the latter. We use a 1.032 bore with 4-pistons in the rear and 2-pistons up front.

smaller bore=easier but more stroke
big bore= hard, quick pedal
too big= "holy ****! I can't stop!!!!"

[Greg Barsamian]

This is a bolt-in replacement for the heavier GM cast Iron master cylinder.

Q. I'm building our '69 Chevelle wagon into a stocker. I'm leaving the rear drums, but am converting the factory front disc over to aftermarket. I've removed the vacuum booster and master cylinder assembly, as well as the factory proportioning valve. I intend to install a aftermarket adjustable proportioning valve. At this point, I plan to adapt a Mopar style master.
Does anyone have any idea if a "plug and play" master cylinder set up is offered? Strange does not make one.

A. This one is a bolt in for what you are doing NAPA part number M2456

[bigfoot584]

On the 13-1945 master cylinder you guys speak of which port
is front brakes the port closes to the fire wall or other one.
Greg, I just did a napa search for M2456 and they show nothing
is the number correct or maybe old?
Thank you

[HandOverFist]

Originally Posted by bigfoot584

On the 13-1945 master cylinder you guys speak of which port
is front brakes the port closes to the fire wall or other one.
Greg, I just did a napa search for M2456 and they show nothing
is the number correct or maybe old?
Thank you

I think it was determined the bore was too small on that first part number...best bet is to walk in a NAPA store and let the counter person do a search for something with a 1" bore or larger. Nearly all the m/c will have a larger tank for the rear system and will be located at the back of the m/c.

[Signman]

Believe Willwood has 2 bore sizes 1 1/16" 1 1/8"
The 1 1/16" will give a softer pedal more travel, opposite for the larger.
Where you want more braking power Front or Rear is where the larger volume section should be plumbed. On a drag car with slicks and narrow front tires the larger volume section should be plumped to the rear.

[Eman]

Unless you have a step bore master cyl, 2 different bore sizes so each port has different pressure, the only difference between ports is the size of the resevoir over the port. Why is that? Well disc brakes are self adjusting by the piston moving outwards as the pads wear. With the larger resevoir the fluid goes into the calipers and doesn't require you filling the MC as the pads wear. Most MC's have the larger resevoir towards the firewall so that's where you can plumb your frt. discs to. Even the Mopar style MC's have a larger resevoir in the rear, you have to look inside the caps to see where the divider is.
I used a cast iron MC from an early 80's Chevy truck, 1 1/8" bore and it has a rod that clips into the piston so it can't fall out. I've also used a MC from an 85 full size Chrysler, 1 1/16" bore. For the Chrysler style I removed the pedal quadrant and welded in a rod guide so there is no way the push rod can drop out of the MC. If converting to manual you need to raise the push rod attachment point to give you a 6:1 pedal ratio. This will give you much better braking and a better feel to the brakes.
There's a link somewhere showing someone converting a Malibu to manual brakes. It has good pics and shows welding in the pushrod guide.

[Myron Piatek]

Originally Posted by Lee Valentine

Mid 80's aspen or volare master works well.

I believe Cardone reman 10-1821 is the one for manual front disc brakes on Aspens & Volares. Not sure what years are applicable between the 1976 and 1980 model year run. You can pick up a reservoir at any U-Pull-It. That's what I use plus I pulled a reservoir out of a full size van or truck, broke off a tab or two underneath, and used that for the higher fluid capacity over the passenger car versions.