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View Full Version : Dual Lever One rear caliper.



shovelheadnc66
09-20-2019, 7:19 PM
Ive had this crazy idea for a while now, maybe someone here has tried this or at least entertained the idea. Im building a 78 shovelhead chopper with springer front end. The springer has some nice patina that im hoping to keep and i dont want to screw that up by welding on a tab to support a front brake. I live in the mountains and a foot clutch with no front brake is not exactly ideal. That being said, what are the chances a feller could run a dual lever single caliper setup without pissing brake fluid all over the place? I have looked into the Fab Kevin dual caliper setups but i feel like they are to bulky for what im going for. Im not really looking for stopping power, i just need something to hold me back on some of these gnarly ass hills around here. To clarify im looking to control my back brake with both my foot pedal and my handlebar lever. If anyone has any ideas or insight i'd appreciate it!

Revelator
09-20-2019, 8:08 PM
an inline check valve installed between the two calipers may work.
otherwise I think the fluid pressure from one lever will force some
of the fluid into the other lever's piston bore and maybe forcing fluid
(from the piston) into the reservoir of the lever that is not being engaged.
just a guess, I've never tried or seen it done.

what about running two of the real small 2 piston calipers, like the ones PM
makes for the springer brake?

DustyDave
09-20-2019, 8:54 PM
an inline check valve installed between the two calipers may work.
otherwise I think the fluid pressure from one lever will force some
of the fluid into the other lever's piston bore and maybe forcing fluid
(from the piston) into the reservoir of the lever that is not being engaged.
just a guess, I've never tried or seen it done.

what about running two of the real small 2 piston calipers, like the ones PM
makes for the springer brake?

If you use a check valve how will the pressure get out of the caliper? The only duel master cylinder setup I ever worked on had a shuttle valve that when a master supplied pressure it shifted to that master to allow flow in both directions until the other master supplied pressure then it shifted to that master. only real problem we ever had with that system was that occasionally one master cylinder reservoir would over fill.
Foot clutch? I almost always ride in the mountains and always run a clutch that will stay disengaged with out my foot on it. Around Santa Fe a front brake is kinda nice to have seems to contribute to your chances of staying above ground.
Pic of my scout idling in gear on the stand I used the clutch pedal off an Indian four that has a release latch.
https://i.postimg.cc/P5yQ34FH/DSCF2195.jpg (https://postimages.org/)
Dusty

Sky
09-20-2019, 8:56 PM
Cable lever tied to the brake pedal

Or

Just use a front master for the rear caliper
Ditch the rear master and pedal altogether

Or

Run a sprotor off the front master
Keeping the "stock" rear brake intact

Or

Add a cable clutch lever
so you can put that left foot down

Or

Find neutral when you stop
N1 drum might help

Or

Feather that clutch like the chopper pilots of old

Or

Clamp on the front brake stay

TriNortchopz
09-20-2019, 9:28 PM
I remember reading about a Yamaha that had a 3-pot rear caliper; the middle pot was controlled by the handlebar lever (along with the front brake), while the two outer pots were foot pedal controlled. Might be something similar out there by whichever company that made that one.

JBinNC
09-21-2019, 4:58 AM
Line Loc?

Jim

MOTher
09-21-2019, 10:14 AM
There was a guy in my area that ran an outfit called Black Swamp* Choppers. He built some pretty nice bikes, won a couple of Penthouse Magazine Biker Build-offs. He did use this setup several times, a single caliper in the rear controlled by either the hand or foot master cylinder. Unfortunately, he did not share the details. He did say that if you tried to use the other lever while you had one activated, it would feel very solid and had no effect on the braking. I think it was some kind of hydraulic either/or valve. I bet if you had a conversation with someone who does or sells industrial hydraulic plumbing, they could help.

* This area of the country west and south of the western end of Lake Erie, used to be called the Great Black Swamp. Many of the very early settlers died of malaria, from the mosquitoes. Over time, it got drained and turned into mostly farmland.

confab
09-22-2019, 12:22 PM
Don't know a great deal about the specifics of brakes, but pressures are equal in a hydraulic system..

So, you can't just hard line it together? Even hardline the reservoirs together if you wanted? Because if one is above the other, I don't see why that wouldn't work just fine.

JBinNC
09-22-2019, 1:13 PM
Don't know a great deal about the specifics of brakes, but pressures are equal in a hydraulic system..

So, you can't just hard line it together? Even hardline the reservoirs together if you wanted? Because if one is above the other, I don't see why that wouldn't work just fine.

That won't work because master cylinders have a bleed port that vents line pressure to the reservoir when the cylinder is at rest. Plumb two master cylinders together, and you will just pump fluid from one to the other, UNLESS both are actuated at the same time.

Jim

farmall
09-22-2019, 1:59 PM
Machine or modify a multi-piston caliper body to act as the above mentioned Yamaha caliper. The middle pot and end pot arrangment is important because it cannot tilt the brake pads.

If you want it to be hydro-mechanically simple and elegant that would be the way to go, and you'd maintain separate hydraulic systems so failure of one doesn't leave you brakeless.