drum to disc?

[DexterZX2]

Is there any reason that one would have to replace the master cylinder when switching from drum to a rear disc brake set-up?

[TTFOWIA]

master cyl I dont think so... proportionning valve definitely.

[DaviDawg]

i didnt put a proportioning valve on mine and its fine.

[JohnP]

Did the swap in '98 , used the ZX2 brake system with the EGT rear disc , work excellent no problems .

[Sir William]

It is not needed. Yeah the proportioning valve is different, but it won't make that big of a difference. So IMO just hook em up.

And if JohnP says so, it's true.... Take that to the bank!!

[DexterZX2]

I thought so. I guy at the yard where I'm pulling the rear disc's told me that. I told him that it wasn't necessary, but I wanted to check with you people just to make sure. Thanks.

[TTFOWIA]

yeah it will definitely work, but on a stock ZX2, braking is 80% in the front and 20% in the back (with drums)... if you install discs without the proportionning valve, it will be 20% braking power on you rear discs. If you do change it. it will become 60-40 (or 70-30 im not sure)

[mechtech]

I can't see it working right without the right proportioning valve. The drum brake system has a check valve in it to keep 2-3 pounds of hydraulic pressure. This will cause drag with discs - they don't have return springs like drums to counteract this.
But it seems the master cylinder is just fine either way.

[JohnP]

Never any problems , the pads don't drag , excellent braking .