Welcome to our resource for MG Car Information.



MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - dual brake circuit master cylinder?

I'd like to keep the original master cylinder, but for safety sake, a dual circuit system would be a smart move.

Case in point, I elected to go with the British stainless braid hoses, but, in researching on the net, they have a history of failing.

Anyone out there adapted a dual circuit master cylinder? My wife is hard on the gas until the very last second and then clamps down on the brakes really hard (think about brake hoses now). Every time I ride with her, I wonder if "we're gonna go together" this time out, and that's with stock hoses. My left hand is always twitching just above the e-brake handle, like I have Parkinson's disease.

The MGA has the 2 bolt mounting, but looks like it wants 2 rods. Likely not enough room?!
Jim Northrup

I had a British stainless braided fuel line fail once, but that was because it looked good on the outside and later failed due to the rubber inside deteriorating, which is impossable to see. With the added pressure, I would think a brake line if bad, would fail much sooner. PJ
P.S. Jennings

Jim - The MGA master cylinder is not a dual brake master cylinder, it is rather, a dual (independent) cylinder with one for brakes and one for the hydraulic clutch. A dual brake master cylinder is operated by a single rod and has a split piston internally. Cheers - Dave
David DuBois

I think you'd have to go to the MGB for a dual 1967 I think...
Bob Dougherty

Mr. Jennings,
A "bad" brake line would probably fail right away. I'm not sure what they use for the inner tube, but the first wire in the braid that breaks can puncture that tube. I could've made some teflon hoses myself, but the rated working pressure seemed too low. I've stood on the brake really hard to check everything out and those hoses have passed with flying colors, but after a few years, lots of turns and bumps, the flexing could take its toll. That's when the dual ciruit is worth it's weight in gold.

Thanks... never would've guessed the two hydraulic master cylinders were clutch & brake. You'd think they'd have stuck to that design instead of independent for the MGB.?!
My impression was 2 separate single brake circuits, sorta like a step in evolution. That would have make the pedal & rods an interesting menagerie.

The MGB unit has a 2 bolt flange instead of the 2 bolts through the side. I can see how someone might drill 2 holes in the pedal enclosure, but it might need reinforcing.

I'm just groping right now to see if anyone else has already blazed this trail and made all the mistakes ahead of me. I'm gonna explore that MGA circuit a bit closer now.
Jim Northrup

OK, looks like MGAs never had a dual brake circuit.
Jim Northrup

Several of the MG T racers have adapted a dual master from a VW Beetle. I think it's from a Super Beetle. There was a how-to document from someone in the MG Vintage Racers group.
Kurt Byrnes

Hi Jim:
If you send an -e- to me I will send you some pics etc on how I did it . . . will be next week as I am on th road.

John Crawley

John...can you post them here as well?
gblawson(gordon- TD27667)


I came across this document for installing a VW dual cylinder into a TC: Might work in a TD/TF?

Matt Davis

Was anyone able to open the url address provided by Matt concerning the brake cylinder conversion?
Jim Merz

Try this with cut and paste in the browser address bar.:
Dallas Congleton

You may find that following Dallas' instructions still fails to work, this is due to a problem with the way this web site handles spaces in urls. Spaces are best avoided in files uploaded onto the internet.

To find the page simply google "tc vw master cylinder".

Matt Davis

Using the copy and paste method with my entry works with my browser, although it doesn't work as a link.

The document is a .pdf file and I will forward it to anyone that wants it as an attachment on an email.

It is for modifying a TC, so some adaptations would be necessary for a TD or TF.

Dallas Congleton

Update on dual circuit brake progess...
John Crawley, thanks for the input.
It was a coincidence John & I selected the same Chevy master cylinder.
This is what we started with...

Jim Northrup

My $25 ebay investment (free shipping!) spent a few hours in the lathe, under the drill press, on the sanding disc, got screwed by a tap, then reamed out...

Jim Northrup

...and brazed...

Jim Northrup

...and brazed, and brazed...
top cover, end fitting...
and note the hole brazed shut on the end, too!

Jim Northrup

...and finally, after about a dozen hours of fun and games, installed.

Have to splice the proportioning valve into one existing line and run 2 new lines from the master cylinder to the valve.

Jim Northrup

This thread was discussed between 19/11/2010 and 17/12/2010

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.