What size master cylinder in hrp pedal box? Help

So Iv fitted a hrp pedal box in my mk1 Iv got g60 calipers on the front and drums on the back, I'm using 0.75 for the front and 0.65 for the rear but I'm not getting much bricking force up front and the rears are locking up this is with the bias fully on the front.
I rang rally design and they said that I should try them the other way round?
What do people think?
Does anybody else run any different size master cylinders any help would be great as I'm doing rockingham on mon!

 

In my view 22mm on the front would be better but what you have should offer decent brakes but require a good prod.

Does it have a bias bar? Are you sure the bias is correct? It sounds like you`ve reversed it.

 

Sorry you have confused me with the 22mm master cylinder, as that's the size of the mk2 golf that does both the front and the back.

I have tried adjusting fully both ways still no good though!

I'm running willwood master cylinders

Front 0.75
Rear 0.625

Is this right? Am I missing something?

 

it should be the other wayround.

 

Oh thanks

 

Start with 0.625" front and rear and test. If you find you're winding the bias bar a long way towards towards the front then replace the rear master cylinder with a 0.700" and recenter the bias bar and test again. I can't imagine you'll ever need a 0.750" on the rear as its way too big, but there again, we're all different with different driving styles, running the 0.750" on the rear may be perfect for you...

 

Hi guys just a quick up date, changed the master cylinders round and I now have brakes! I took the car round rockingham and the brakes were faultless and they had great feel considering I'm now running no servo.
I'm running g60 calipers with 280mm discs and 2500 pads with blue racing fluid I had no fade and really good bite, I was pushing around 120mph round the half bowl at the rock so it was a good test for them.
I'm now going to try and adjust the bias to see how much rear braking force I have,
Thanks for the quick reply

 

Great news!

So were you running 0.625 front and 0.750 rear with the bar centred?

 

Sorry for the hijack but does anyone know what size clutch master cylinder would be needed to operate a standard 02A slave cylinder?

 

0.75" with 1/4" line

 

Thanks Mickey, is that 1/4 external diameter?

 

Yeah.. next size up from 3/16 brake lines. I think the factory use 6 or 7mm for clutch.