Brake Master Cylinder

[drndrn]

Hey fellas,

I've recently upgrading from the 2.5NA brakes to GT/3.0R brakes. I was told that I would need to replace my brake master cylinder too to get the most of this mod. Is this true? Or do all Lib's share the same master cylinder?

Any info would help.
Thanks

Darren.

[senator]

i think they a same BMC…I think, no point changing it unless your increasing the diameter of your rotors significantly.

[drndrn]

Well.. The standard NA brakes were 277mm (I think) and the current GT's are 316mm. So does that warrant a change?

[smythie]

It's not really rotor size that you would change your master cylinder for though is it?

I would have thought you might change master cylinder to match a possible change in effective piston areas (remembering a twin piston sliding caliper will have the same effective area as a 4 piston opposed that has similar sized pistons). And you'd only be doing that if you thought the increase in effective piston areas across the car was big enough that you would run out of piston travel in the master cylinder during normal operation.

I wouldn't be changing master cylinder unless I had radically changed the effective piston areas (different calipers)

Happy to be corrected though

[senator]

It's not really rotor size that you would change your master cylinder for though is it?

I would have thought you might change master cylinder to match a possible change in effective piston areas (remembering a twin piston sliding caliper will have the same effective area as a 4 piston opposed that has similar sized pistons). And you'd only be doing that if you thought the increase in effective piston areas across the car was big enough that you would run out of piston travel in the master cylinder during normal operation.

I wouldn't be changing master cylinder unless I had radically changed the effective piston areas (different calipers)

Happy to be corrected though

+1,

[Jimmy S]

I wouldn't worry about it...

I am changing from the GT brakes to the STi Brembo's and leaving the master cylinder as is! I don't expect that there will be any issues, although I haven't got it back yet!

[jdm rsk]

i went from front 2 pot 275mm, rear 1 pot to front brembos 327mm and rear 2 pot and didnt change it....

[tangcla]

Changing the master cylinder will affect the pedal feel, put the rotors/calipers on first and see how it feels. With more reservoir it will give... more? or less? sponginess.

[Kevlar GT]

Just go and buy a cusco top strut brace with brake booster and it will sort any spongy feel and stiffen the front end up some more. I have the Brembo's up front and said brace and it has not shown any poor feel.