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MG Midget and Sprite Technical - Brake Master Cylinder swap

Is it possible to change the normal single line brake master cylinder for a later duel line one.

My car is a 1968 Midget (ex motorshow demo car according to the Heritage Certificate) although it will soon be a lenham
Martyn Wilks

Yes and no...

It could be swapped, but it would require some modification to the pipework also.

The single circuit set up has two pipes from the M/C (both part of the same circuit, obviously). One leads to the front right brake, the other to a junction that feeds the other three wheels.

For a dual system, the two pipes exiting the M/C are separate circuits (again, obviously) that lead to a junction box, where one pipe branches off to feed the front two wheels, the other pipe feeds the back wheels separately (similar to single circuit lines).

All the piping mods could be done in the engine bay though, if that helps. No need to mess with anything under the car.

Hope this helps,

M Le Chevalier

Are you sure Malcolm? I thought on the single system a single pipe goes from the M/C to a 5 way junction which sends two pipes to the front brakes and one to the rear where it goess into another junction to feed the two rear brakes?
Jeremy Tickle

Confusion between models.

Single circuit 1500s did have two pipes from the m/c, whereas earlier models had one, as Jeremy described.

Dave O'Neill 2

Cheers Dave, but I think Martyn's is a '68 model.
Jeremy Tickle

Yes, I realised that, but Malcolm's isn't ;o)
Dave O'Neill 2

Thanks Gents car is a total full nut and bolt rebuild on a heritage chassis I found so lines etc are no problems, was thinking of a triple master cylinder pedal box but I can't see how to get three cylinders into standard box unless someone has a drawing
Martyn Wilks

I think Prop has done this conversion to his?
Jeremy Tickle

OK, sorry for the confusion, didn't realise single circuit layouts changed over the years.

I was describing my early 1500 layout as Dave twigged.

M Le Chevalier

I think you also need a shuttle valve to prevent, in the event of one of the circuits failing, all the fluid from one circuit escaping out of the leak in the damaged circuit.
Graeme Williams

All the shuttle valve does is operate the warning light switch, so it's not necessary.
Dave O'Neill 2

Martyn, it's possible to have a 3-cyl pedal box, peterMay does one, this is an improved redesign of his previous version. Classic Car Clinic in Netherlands used to do one too, I have this on my race Midget. I also think there are some home-brew designs around, some require the pedal box hole to be enlarged, others don't. I presume you want a balance bar for front/rear split?
David Smith

This thread was discussed between 11/11/2015 and 14/11/2015

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