BRAKES!

Racing5150Guy

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i was wondering what i can do to get rid of my power brake booster on my 73 chevy pickup. i was thinking some sort of cnc master cylinder. it still has all the stock brakes. i am going to put disks in the back though. let me know what you guys think.
 

ntsqd

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If the front brakes are the stock 2-15/16" piston GM calipers you're going to want a m/c with a bore in the range of 15/16" to 1-1/8" depending on pedal ratio and how you want to brakes to feel.
Try pulling the check valve out of the booster can and then see how the brakes feel. That will give you an idea of if the current m/c will work. Pulling the hose off the check valve is not the same thing and won't give you worthwhile results. You'll have to remove the hose from the intake and plug the port to drive it. Be very careful at first, doing this may not leave much braking.
Most m/c's you will find made for rear discs will be power applications. You can make a proper length pushrod to use them in a manual application, but you ABSOLUTELY POSITIVELY have to make sure that the pushrod can not escape from the m/c bore. You also need to pay attention the shape of the nose of the pushrod to avoid premature wear of the m/c's piston.
You can convert a front disc/rear drum m/c to 4 wheel discs by removing the RPV in the rear brakes outlet.
You will likely need either an LBS (perferred) or a prop valve for the rear system.

TS

I used swerve around my halucinations, now I drive right thru them.
 

Racing5150Guy

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ok well i have tried to stop with no power booster and there is like no way. i am also running a 35 inch tire and a heavy @$$ truck. so if i put a 11/8" master cylinder with a 7:1 pedal ratio would be about the best stopping power i could have without upgrading the rotors and calipers. your help is appreciated though.
 

dezerts10

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you have the right guy helping you he help me a lot when i was doing my brakes. Thom knows his stuff.

Gregg
 

FABRICATOR

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Gregg is right about ntsqd helping you with brakes. Keep in mind that a smaller master cylinder bore (like 7/8") puts out more pressure and less volume. A bigger bore (like 1-1/8") puts out less pressure and more volume. Calipers and slave cylinders are the opposite; bigger piston area provides more braking pressure. System design and component selection must include attention to both pressure and volume.

<font color=orange>The best ideas are the ones that look obvious to the casual observer.</font color=orange>
 

ntsqd

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Did you remove the check valve from the booster ? This is crucial to the experiment. If you didn't you will have the worst brakes, that still mostly work, that are imaginable.
If you did remove it, then we need to know what the pedal ratio is and what the caliper piston size is, or tell me what vintage truck or calipers you have & I can find the piston size.

Hyd Leverage is a ratio. Sort of like a compression ratio. Small bore driving a big bore equals not much distance traveled, but a lot of force (Brakes). Big bore driving small bore equals not much force, but a lot of distance (Hyd. Clutch).

TS

I used swerve around my halucinations, now I drive right thru them.
 

Racing5150Guy

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thanks for all your help. i just wanted to make sure that that was a step in the right direction taking it off. so now that i know what i need to do what is everyones favorite brands. i was thinking of doing something like a cnc setup with there swing style pedal mount. what is everyone else running.
 

ntsqd

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Well my favorite brand is Wilwood. I might be biased a little.....

Our new High Volume M/C is lighter (!) than the old Composite M/C and has far better cap and seal design. Leakage in the rough will be a thing of the past.
Unless you want to go to the dual m/c system, the tandem M/C we offer may do what you want and work with your existing pedal.

TS

I used swerve around my halucinations, now I drive right thru them.
 
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