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Author Topic:   dual master cyl
bryanb30
Dirt Forum Racer

Total posts: 98
posted January 27, 2003 06:53 PM
i have two willwood 7/8 master cylinders and a cnc brake pedal with the balance bar. how should they be set up?, one for the front and one for rear or should it be one for left side and one for right side, and rules say we can use a brake valve, but not within reach of the driver. and for that i have a lever style brake valve.

outlawstock17
Dirt Forum Champ
Total posts: 620
posted January 27, 2003 07:33 PM
one for the front and one for the rear. ideally, you should have a 7/8" on the front and a 1" on the rear, assuming that you have metric calipers on both ends. the smaller master cylinder will produce more pressure while the larger diameter one will have more volume.

[This message has been edited by outlawstock17 (edited January 27, 2003).]

dirtracer7
Dirt Maniac

Total posts: 106
posted January 28, 2003 11:45 AM
One thing I found out last year about 2 masters with balance bar is if you break a line or empty the fluid in one resivoir you have almost no brakes.Stick your feet on the ground like fred flintstone would do or yaba daba do.

marty
Dirt Maniac

Total posts: 111
posted January 28, 2003 04:41 PM
Hi. This might help a little. I would say that you are in the ball park with the 7/8 bore master cylinders - run one to the front & the other to the rear (just adjust the balance bar to reduce the braking on the rears). Something to remember if you do change master cylinders is that if you go to a larger bore (1") you will need less foot effort to achive the same braking effect but this is traded off against having to put up with a little more brake peddle travel (the opposite applies to a smaller bore). If you have a variable brake tap I would put that into the right front brake line as reducing this will aid turn in.

bryanb30
Dirt Forum Racer

Total posts: 98
posted January 28, 2003 05:34 PM
reduce the braking to the rear... is this gonna help the car turn when i get on the brakes? thanks alot for the info..

c21
Dirt Freak

Total posts: 346
posted January 29, 2003 10:48 AM
quote:
Originally posted by marty:
Hi. This might help a little. I would say that you are in the ball park with the 7/8 bore master cylinders - run one to the front & the other to the rear (just adjust the balance bar to reduce the braking on the rears). Something to remember if you do change master cylinders is that if you go to a larger bore (1") you will need less foot effort to achive the same braking effect but this is traded off against having to put up with a little more brake peddle travel (the opposite applies to a smaller bore). If you have a variable brake tap I would put that into the right front brake line as reducing this will aid turn in.


Marty, Brake pedal effort is proportonal to Master Cyl. Bore size and Pedal Travel is inversely proportional to Master Bore size.

In other words : a larger diameter master (all else being equal) will increase effort and decrease pedal travel .The opposite relationship exits at the slave (caliper in the case of disc brakes).

c21


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