Opinion Wanted: Dual Master Cylinder

1941 - 1945, MB, GPW modifications, sugestions, and ideas, official MWO's and unofficial WWII field mods NO EBAY or COMMERCIAL SALES.
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W. Winget
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Re: Opinion Wanted: Dual Master Cylinder

Post by W. Winget » Sun Feb 09, 2020 2:59 pm

Nice clean work.
Perhaps turning a repop oil can into a reservoir with the removable spout as the fill and a soldered fitting in the base that would clear the oilcan mount...
This way short of an eagle eye spotting the line under the mount the install might be invisible.
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Looking for 1918 Standard B 'Liberty' truck parts


Marty, SoCal
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Re: Opinion Wanted: Dual Master Cylinder

Post by Marty, SoCal » Thu Jul 30, 2020 3:49 pm

I measured one of the golf cart 3/4" bore master cylinders, (actually mounted on an E-ride utility cart at my work). The bolt spacing where it mounts to the frame is 3-1/2" center to center. The pushrod is 5" long. Looks like the plastic reservoir can be reversed if needed, which might make it align with the floor opening better.

Image

I'm going to scrounge one off a scrap cart and try it for fit on my GPW. Will update!
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bryanbdp
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Re: Opinion Wanted: Dual Master Cylinder

Post by bryanbdp » Mon Aug 24, 2020 5:10 pm

I went with vented Geo Tracker brakes in the front, stock drums in the rear.
I worked up my own measurements and created a bracket similar to the one Herm sells.
I used a Centric 13063010 master cylinder from Rock Auto ($41 new). Fits CJ5 70-77 among others.
This master has that weird boss on the bottom. I read that it was for a stop pin.
Turns out, it was used for a stop light switch in some applications. It can be used as the front brake line port with a brass adapter. I called Centric to confirm it was OK. This allows you to plug the original port, which is really close to the bellhousing. It looks like a custom heatshield will be needed though, or mods to the original.
I used the adjustable proportioning valve and 2 and 10 lb residual valves.
I used a power bleeder to bleed, interestingly, even with 15 psi fluid wasn't flowing. I pumped the brakes a couple times and the fluid came, brakes are solid as a rock. They seem to work great from the limited driving I've done so far.
top view.jpg
Top view. Using modified original pushrod, threaded further up rod and will shorten to fit as needed.
Installed a brace from bottom of bracket to crossmember, there is also a tab on the bottom that supports the pedal shaft.
Used rod ends on clutch linkage, they work nice.
rear view.jpg
In this view you can see the brake lines from the MC entering the proportioning valve at the rear. The rear brake line with 10lb residual valve heads to the rear inside the crossmember. You can see the rear brake adjustment knob and the stop light switch.
rear port MC view.jpg
Here you can see the rear brake line, and the blocked off front port
rear brake line and resid press valve.jpg
rear brake line, clamps not installed yet
proportioning valve.jpg
here's another view of the valve, a simple bracket attaches it to the spring bracket.
master cylinder top view.jpg
master cylinder bottom view.jpg
Here's the bottom of the master with the front line coming out
brake pedal and rod view.jpg
Last edited by bryanbdp on Mon Aug 24, 2020 5:19 pm, edited 1 time in total.
45 MB - W Simsbury CT
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bryanbdp
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Re: Opinion Wanted: Dual Master Cylinder

Post by bryanbdp » Mon Aug 24, 2020 5:17 pm

Here's the print I created for the bracket.
master cylinder bracket.jpg
master cylinder bracket drawing flat.jpg
45 MB - W Simsbury CT
Built to drive!

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tamnalan
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Re: Opinion Wanted: Dual Master Cylinder

Post by tamnalan » Mon Aug 24, 2020 6:14 pm

Very nice!
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