Master/slave Cylinder Wear

[2LV8ETR]

Greets guys.

A little while ago I put an R33 manual box into my auto R32. Since the conversion I have problems changing up through the gears where each selection crunches when changing at >3000 rpm. The clutch used is a 9 puck ceramic item with a custom 2.5 ton pressure plate.

I believe I have found the problem to be my master cylinder.

Last week I lost most of my clutch and when I tried to bleed the line, I found the fluid to be black in colour. I have put this down to wear of the seals in the master cylinder.

The kicker is that I bought the master cylinder new from Coventry's and that was only 2 months ago. At the same time I bought this, I had the seals in the slave replaced at the same time.

I think I need a master cylinder with a bigger bore to give me more throw with the clutch to stop the grinding through the gears, and this should hopefully be strong enough to cope with the increased seal pressure that the pressure plate is asking for.

Does anyone know what is out there available or does someone know something that I don't that could be another issue? Would an R33 master cylinder do the trick?

The brake/clutch specialists I have spoken to over here in WA don't know the answer.

Any help would be greatly appreciated.