Discovery 1 / RRC Master Cylinder Upgrades

[Readie]

Hi All,

I have converted my rear axle to front brake callipers on my challenge Range Rover Classic.
Lets just say it wasn't my greatest move although the brakes have plenty of power now.
The trouble is now to get full braking you have to punch the brake pedal twice in quick succession, I have bleed the whole system up and once you have pumped the pedal twice the pedal remains firm and solid with the brakes locked (aka I don't appear to have a leak on the system or believe I have any air in the pipes). I have come to the conclusion that the master cylinder is too small to meet the extra fluid requirements of having 4 pot callipers right the way around?

Does anyone know of any larger master cylinders that will fit the existing servo/pedal?
Or alternatively I have heard some old lorries (pre air) had a pressure booster in the brake lines but haven't had much success researching these?

Cheers,
Readie

[Carloz]

I don't understand this "upgrade" It makes your car dangerous!

What you said: you created a problem with this move: To get a firm pedal in the first attempt you need a bigger diameter master cilinder. What you also get is that you have to push the pedal harder to get the same braking effect.

I advice you strongly to put the normal callipers back on! With this setup you have a big chance to block your rear wheels and end up in a ditch or so..

[hangover]

I agree with Carloz, there is a reason why there are 4 piston calipers up front and 2 piston calipers in the rear, the front handles around 60% + of the braking which prevents rear lockup and you heading off the road.

[Arjan]

Yes.. Return to the original set up.

If set up properly it works very, very well.

 

[Team Idris]

I think you need both four and two pot calipers on the back to work properly. Because Milner fiddle brakes are too big in the piston for landrovers.

if truth be told the job needs four pot all round and a bias valve set that operate by direction, but that's harder than fitting abs.

going back to the original question it is normal for the four pot to work fine with the standard master cylinder so it must be air or the calipers mount isn't on square?

[Readie]

Thanks for the reply all. I'm going to take the advice and head back to standard callipers. Sorry for the late vote of thanks, my account didn't notify me of the replies.

Cheers,
Readie