2 Master Cylinders for Rear Brake? Will it work?

2012, TE511 - Does anyone know if this will work? I installed an EFM Auto Clutch, rendering my stock clutch master cylinder useless. What I wanted to do, was to run a custom line from the Clutch Master Cyl, to the Rear Brake Caliper, connecting it with a double banjo bolt on top of the existing rear brake line. Hopefully, allowing either the foot pedal or clutch lever to activate the rear caliper. Will this work, or will either Master Cylinder simply push fluid into to other Master, overfilling it and possibly out of the system?
My alternative is to run the LHRB only with no foot brake option.

The more I think about it, I don't think it will work without some sort of shuttle valve. Comments or suggestions are appreciated.

I don't know for sure but I also think that one of the master's will simply pump fluid into the other, like when you compress the piston installing new brake pads.
Using on-way valves does also not work IMHO because once you start breaking the pressure goes up but cannot return to the master cylinder(s) resulting in a permanent brake....

Doesn't seem to be easy to do, but maybe I'm wrong ...

Cheers

Lots of the BMW G450X guys have done the EFM clutch set up in the BMW Kymco engine and have had the same idea that you have now.

For reference though. The Rekluse left hand rear brake on my newer '15 Husky FE 501 is connected to the pedals master cylinder on top of this sleeve fitting that uses the reservoir caps threads and it extends to the bottom of the rear brake masters reservoir. Allowing the reservoir to be pressurized. This sleeve has a seal with an o-ring that keeps the sight glass from blowing out.

Then this barrel sleeve screwed in the rear masters reservoir allows the second brake lines banjo fitting to be attached. Of coursed this LHRB has its own radial style master cylinder lever and the line is specific but I believe using the clutch lever as the master it would activate the brake just fine. If you can effectively bleed it.

This system I have is bled using 2 syringes, It takes less than a few short minutes to do this by 1 person. 1 syringe is filled with fluid and attached to the bleed fitting from the rear caliper with an attached hose and small pinch clamp that comes with the LHRB kit. it is held upright to make any air bubbles rise. The bleed fitting is cracked open and you simply push fluid through the system up to the other syringe, which has a smaller hose that goes on a small tapered seat bleed fitting just for this on the LHRB lever. So the fluid is pushed from the rear calipers syringe all the way up to the other syringe until no air is in the system. Which can easily be seen in the second syringe which is held upright on the levers fitting. Now carefully remove the tapered fitting and syringe and install the levers plug. The LHRB lever is rotated on the bars and set or held level to do this. The LHRB Radial levers fluid reservoir cap is never removed or even opened. Without that bleed fitting up on the levers master cylinder it would be near impossible to get all the air out of the system.

If you change rear brake pads you must open the levers bleed fitting to release some fluid just to compress the rear brake calipers pistons to in order to change pads. Its easy with the syringes. By the way I use one of the syringes to also bleed the Hydraulic clutch from the slave back to the lever. It took about 2 minutes to do this when I installed the Rekluse clutch and adjustable slave cylinder.

Never again will I do this manually by pumping the lever and cracking open the bleed fittings.

This set up works well and the pedal and lever can be used at the same time if you want. The rear brake pressure modulation can easily be felt through the foot pedal and vise versa at the lever. Which is very nice.

You could run the line directly to the rear caliper easy enough and remove the pedal.

Their are other options. Slavens has a hydraulic LHRB from "Smokin" that is about the same as the Rekluse LHRB I run pictured below. It will plumb either way, for retaining the pedal or connected directly to the rear caliper depending on which kit you buy. Not that you want to buy a kit. I'm not trying to sell you anything here. I'm just showing you what the fittings look like to do it. They do list a kit for your bike as they are made for Brembo masters and calipers.

They also have the "Ox brake" that is a cable operated LHRB set up that attaches to the rear of the pedal. I'm not saying this will fit your 511 but it gives you the idea of another way to do this.

Wow, thanks Tim. You have provided great information.

Well, it worked fine thanks to Tim's advice. Purchased the special sleeve from Rekluse $100. Had the drill out the 8mm hole and tap for a 10 mm banjo fitting. Purchased a nice hose online from cycle-brakes. Installed and bled. Works good with foot or hand lever.

There you go. I knew you would like it.
Just wait until you have to Bulldog wrestle that bike down a really steep hill after a get off and you are unable to re-board the bike until you are on more stable ground.
You will really like that left hand rear brake then. Since the bike wants to roll with the auto clutch in gear when the engine isn't running.
You will nearly have a quick "Deja Vu" moment, remembering how nice it would have been to have that LHRB lever to do this all the other times.
Some people might say "Oh its not necessary, what do I need that for" ?
Then again they wouldn't know the difference. I don't let them ride my bike either so they won't know the difference.