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"G" Valve needed or not needed

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The Excel Service Parts List shows a G valve in the brake line to the rear brakes.

There is opinion that this is not needed on cars fitted with rear discs instead of drum brakes.

What are your thoughts, please?



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AFAIK, it's got less to do with the type of brake than the propensity to lock rear wheels under severe braking. If it's originally fitted, then it's needed even on a disc brake axle.

Cheers, Richard

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As you brake increasingly "vigorously" the pressure needs to be limited to the rear of the car to stop the rear brakes locking due to the induced weight transfer (to the front) by the braking process.  The valve does this.  Without it there is a good chance of locking the rear brakes leading to a spin.  The front brakes should always lock first.


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Thanks for your comments

I understand the reasoning behind fitting the valve, but, am i right in thinking that the Elite and Eclat  does not have such a valve, and what changed between them and the later Excel to warrant it other than the introduction of rear discs instead of drums which is supposed to be the better braking system. Or was it just the thing to do at the time?

There is a lot of discussion on Land Rover Defender forums that had them fitted and then didn't

Any Excel owners care to contribute/

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