Lagondaforum

Subject: v12 master cylinder

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the V12 has a 1 1/4'' lockheed master cylinder, but if we replace it with a 1 1/2'' master cylinder without changing anything else, would it work?

Subject: Re: v12 master cylinder

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Dear Awini: Ratio of areas of the pistons is the ratio of the diameters to the square, so you will have 1.44 fold area and you will have to press 1.44 fold harder for the same brake effect, but at the same time with less pedal travel. The new master cylinder must allow at least 70% of the travel of the old one.
Why do you want to change?

Subject: Re: v12 master cylinder

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As Peter says, it will work, and pedal travel will be less...but you will have to press significantly harder to achieve the same level of braking. The result potentially is that you might not be able to press hard enough in an emergency stop situation, and in any event you could find the brakes tiring to use in heavy traffic.
If your request is simply that you've been unable to obtain the correct master cylinder, you could have the new one sleeved to 1.25", using stainless steel so no rust in future!
Laurence

Subject: Re: v12 master cylinder

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I Fully aggree Laurence.

Just for completing the theoretical side: you could compensate the described effect of the larger cylinder by moving the connection point to the brake pedal closer to the pivot point.

But it is always better to save the original configuration

Subject: Re: v12 master cylinder

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Hi Guys,

Has anyone had experience of fitting a servo on a V12? Would it work?

Colin

Subject: Re: v12 master cylinder

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Easy peasey,

Use two MGB remote servos and tuck them up under the chassis,
These can be had from Europa spares or Holden vintage for small money and work fantastic!
They fit nicely either side of the gearbox tucked up inside the X member and plumbed into the front and rear circuits individually.

Phone me if you need more advice. +32 489 712 608

Regards,
Julian

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