Master Cylinder Problem

[wlspn]

I have upgraded the single-piston calipers on my 32GTST to 33GTST 4-piston fronts/2-piston rears & since doing so my brake pedal has never been right. The brakes have been properly bled, bleeder is at top. The first half of the pedal just feels like free-play... Has any1 had this problem before? I have the 33 master which I may fit to try & solve this but that requires a custom steel line... Any help would be appreciated

[Moodles2]

Get a friend to pump the brakes while you examine the cylinder, how far is the cylinder flexing?

[Wacky Dee]

r33 and r34 brakes commonly feel very soft at the top ... apparently the master cylinder is just too small according to a few people I spoke to. I've had my brakes bled today (new rotors and pads also) and it's still soft at the top ... like 2-3cm is just mud.. apparently common on 33's and 34's.

[badhairdave]

You will need to change the master cylinder. You currently have one of the smallest masters and you are trying to move a lot more fluid when you use the bigger brakes so you get a long pedal. It's that simple.

The bias will be out also.

Are you sure it was a gtst and not a converted gts?

Get a 32gtst master off a car with the 4 pot front/2 pot rear brakes. It will save you the hassle of messing with the lines and the piston size and bias will be right for the car

Edited May 31, 2009 by badhairdave