Fitting a different brake master cylinder

Rebuilding, adjusting, maintaining & alternatives
Hallo to you all after a forced absence from the Moggy scene of a few years. As a quick re-cap, I have a 1098 Traveller with 940 head and a few other mods. Just about to fit a Ford-based front disc conversation as I have finally given up with the 9" Wolseley drums and difficulty of sourcing replacement shoes. Somewhere in the dim past, I recall a post by someone who had created the makings of an in-chassis modern dual-circuit master cylinder replacement, as I would ideally go for this over the standard single circuit (non top-hatted) option. Has anyone experienced this or have any further thoughts? Many thanks in advance, Pete.
Linear.audio
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I reckon a post-1968 Beetle master cylinder should do the trick. They come in disc & drum varieties and are 0.75" bore, so shouldn't need a servo (remote servo for a tandem m/c is £300+). They are also designed for underfloor mounting and can be used with a remote reservoir.
twincamman
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Thanks, that's food for thought :D
Linear.audio
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Hi Linear

Welcome back!. I had noticed that you had gone missing.

Anyway, this might be the type of MC you were thinking of:

https://www.minormagic.com.au/collectio ... -instructi

This is based on a Mazda 323 / Ford Lazer MC.

Don
don58van
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Hi, Don, thanks for the input, and for remembering me! Unfortunately when I tap Mazda 323 into my all time saviour (EBay), it displays with reservoir on top, which would be a niggle to re-site, as I wish to keep the standard mounting position in the chassis, but with dual circuit and remote fluid reservoir. The idea given by Twincamman of using a post 1968 VW Beetle looks worth some exploration, eg VW KARMANN 1.6 Brake Master Cylinder 70 to 74
( EBay UK ref 332450430439 ), and at £38 warrants some further thinking!
Attachments
VW Beetle master cylinder.jpg
Linear.audio
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Also the VW unit has a built-in brakelight switch.
twincamman
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Yep, noted that :D Just got to do a bit of thunking about the bore size difference, but then again, the 7/8 or 13/16 Moggy ones were never intended to operate disc brakes, yet appear to do so, with the odd comment here and there about a "wooden" feel, so maybe going down to 3/4 " may not be such a bad idea?
Linear.audio
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The smaller bore will mean a lighter pedal (i.e. you won't need to push so hard), but slightly longer pedal travel. If you get the pedal ratio right, the extra travel won't be a problem.
twincamman
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I wish to keep the standard mounting position in the chassis, but with dual circuit and remote fluid reservoir.


That is what the 323 / Lazer kit provides. The kit I referenced in my earlier post bolts straight in where the original mc sits (using the same bolt holes. It is actuated by the unmodified mechanism from the brake pedal. The kit provides a [url]remote reservoir[/url] in the engine bay.

This is a very common upgrade here in Australia and has been so for decades. There must be many hundreds of Minors equipped this way. There are various suppliers of the kit here (in Oz) and some choose to assemble the parts and install themselves.

Don
don58van
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The reservoir simply pulls out of the MC and is replaced .by a couple of adaptors to connect to the hoses from the remote tank. The whole issue will fit comfortably under the floor
John G
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don58van and johngrigg. Thanks very much for your input, it has been a great help regarding the "how to achieve" side of the project. My splitting it down to component parts is not down to my ignorance of your readily provided answer, but as I live in UK I need to adapt to parts readily available over here, as postage from Australia may be rather prohibitive! The modification I initially recalled was far more complex, so "adaptive engineering" has obviously taken a lateral shift since those days (2011 ish)!
Linear.audio
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Re: Fitting a different brake master cylinder

Postby emjay » Mon Jun 11, 2018 3:36 pm

A few years back someone on this side of the Pond mounted a master cylinder on the floor of the engine bay with a linkage to the pedal that came out of the upright panel below the rack. A push rod attached to the pedal above the pivot would do the job. On RHD there is no limitation due to the exhaust and any master cylinder can be used.
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Emjay: Sorry for not getting back to you, but I was confronted/set back by finding a chunk missing from the front lower trunnion, which led onto draining and refilling dampers and converting to taper wheel bearings, etc,etc! I have seen a beautifully crafted device such as you speak of, lurking in the pages here, but the machining requirements were beyond my tooling levels! Anyhow, the VW based cylinder lines up with only a bit of inventive steelwork, even the dual circuit outlets line up neatly. Now the question is front/back or diagonal for the duelling? Most popular seems front/back.
Linear.audio
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