Master cylinder question
 

I have a 15/16 and a 1-1/16 bore MC, whitch one will give the softest pedal effort? I had heard this before but can't remember.
Mike

Re: Master cylinder question
 

15/16

Re: Master cylinder question
 

Thank you

Re: Master cylinder question
 

You need to match the piston area of your calipers to the bore of your MC to get the best stopping power. Smaller bore give higher pressure if the pedal ratio is right.


Joe's Racing has a good article on Master cylinder math. Link below.


https://www.joesracing.com/rt-4172-m...nder-math.html

Re: Master cylinder question
 

15/16 on all our stockers........

Most of our cars are 4 Wheel Aftermarket Discs.

Re: Master cylinder question
 

Pulled the snap ring from bore, saw its 1" just like the factory cylinder on a 70 Duster. New aluminum two bolt like factory, has the groove for rod lock. Bought at Carlilse in a box of parts, mc adapter, coil overs, a-arms, heim joints, proportioning valve and 10 lb residual valve, many misc parts, all for $100, all new. I'm using Strange disc on front, drums on back.
Thanks for replys
Mike

Re: Master cylinder question
 

Try it.....It will probably be fine.

It is a little subjective as different folks like
a different petal feel.

Re: Master cylinder question
 

I guess I'm an odd bird. When I was driving my Mustang to the track it had power brakes and I liked the ease of staging and always hitting the first turn off. When I put it on a trailer and went to manual brakes I never adapted to the feel. Now I'm back to power with a Strange master, a vacuum pump and reservoir tank. Much more comfortable with the way the car responds.


Note: I'm 71 and don't have the leg for it any more...

Re: Master cylinder question
 

With all other aspects the same...
a smaller MC bore will require more stroke with less effort to reach equal braking pressure (providing the volume is still adequate).


a larger bore MC will require less stroke with more effort to reach equal braking pressure (larger is required when caliper volumes are greater)


Larger- multi piston style calipers "generally" have more piston area so they will provide more brake application force at lower pressures. ie. they work in conjunction with the larger bore MC.

Re: Master cylinder question
 

Your call but I don't think you'll need a proportioning valve or a residual check valve, every car is different. I've got GM Metric calipers on the frt. and drum on the back with an aluminum Mopar MC 1 1/16 bore with no ck valve and I have an adjustable prop valve but it's wide open.
What works for me footbraking is the largest bore rear wheel cyls and secondary shoes in both positions for more friction surface area.

Re: Master cylinder question
 

Not looking to use the proportion valve. My first Duster had the stock Kelsey disc up front with a drum brake master (like the one I measured) and that car was the best stopping bar none. Hope to get the same feel again. Of course I was 29 then, might not have the leg now lol.

Re: Master cylinder question
 

I just bought a new strange MC. Their recommendation is with 4 wheel disks, use a 1.125 bore and with 2 wheel disk, 2 wheel drum to use a 1.032 bore. I can say, without even bleeding the lines the pedal feels good, better than the mopar aluminum one I had on

Re: Master cylinder question
 

Dont forget to look at break pedal ratio when changing from power to manual.

Re: Master cylinder question
 

What differences are there between the Strange MC and the Mopar aluminum one? Isn't the Strange basically an aluminum Mopar MC?

Re: Master cylinder question
 

Thanks Brian, the one I have is a Strange. The 1.03 one, was in a k-frame kit for a 63 b-body (wasn't used) witch is ok since I'm using a 64 pedal. How is your car coming along? Who is gonna be out first, LOL?
Mike

Re: Master cylinder question
 

Not sure what the differences are. the mopar one might have had an issue, Although one thing I did different going from one to the other is that I now have the rear brakes plumbed to the rear port on the MC. I read that the rear port provides more fluid flow, and I'm trying to make sure I have good holding power on the rear when staging. we'll see.

Re: Master cylinder question
 

Hey Mike, pretty much done here. Front alignment next week. engine has been on the dyno and I've driven it around the neighborhood, which I very much enjoyed, not sure about my neighbors !

Re: Master cylinder question
 

Unless it's a stepped bore MC, 2 different size bores in one, the only difference in ports is the capacity of the reservoir. Disc brakes are self adjusting by allowing fluid to take up the space as the pad wears so the reservoir is larger.

If you want more holding power in the rear increase the size of the wheel cyls or calipers.

Re: Master cylinder question
 

I've got strange discs in front and back with their recommended MC. I'll wait and see how that works.

Re: Master cylinder question
 

Oh, you are my envy. I can't even push mine around the shop yet.
Mike

Re: Master cylinder question
 

A smaller the master cyl piston bore will give you longer the brake pedal stroke with a corresponding increase in brake pressure.

When expermenting it's best to do it with a brake pressure gage, shoot for around 1100#.

Re: Master cylinder question
 

I bet. how many projects you got going on over there ?

Re: Master cylinder question
 

Too many, but pushing hard to get this one done for spring. Just took on a big cabinet job so there will be some long days. Let me know when you go test.
Mike