Brake master cylinder

[Scott rhodes]

What are most of you running for master cylinders on disc brake conversions. I was going to run a 944 master because it comes biased out of the box,any thoughts would help.

[Craig Richter]

Scott,
Are you referring to one of the front disk brake kits that many of us fit to our drum brake cars, or to converting to complete late 356 disk brakes? I think the most reasonable answer for the complete late conversion is to use all corresponding Porsche parts. With the front only aftermarket disk brake kits, there are some choices. I have used three different brands. The first was a really trick looking "dune buggy" brand, and was an absolute waste of time and money. Ended up throwing 1K in the trash. The next two brands, both now sold thru our normal 356 suppliers, were/are both great. Different looking rotor adapters and calipers, but both ended up working bitchin'. Follow instructions.
Of course, I had to play around. Single circuit MC, dual circuit MC, check valve in MC (supposedly to relieve pressure to front calipers so they wouldn't drag), pressure check valve in rear brake line (supposedly to hold pressure to rear wheel cylinders so they could respond more quickly). Bunch of crap. Nothing worked better than stock drum brake single circuit MC.
Pedal will be firm, not much "squishy". Adjust rears a bit loose to get more modulation. Actual braking force will only be a little better than good front drums, but now both front brakes come to work at same time, not like cold drums, stop nice and straight. You'll like the conversion.

[Scott rhodes]

Thanks Craig
I am going to put disc brakes all the way around. I would like to use CSP systems, and they suggest dual circut master. Thought the 944 might be the way to go. Thanks for your insight it sure helps when people who have done this can respond

[Craig Richter]

Dual circuit MC could never hurt I guess, but when was the last time you experienced complete hydraulic brake failure? Maybe Jack with his vast reservoir of experience has seen or heard of it, but I have not. But if you had experienced such a disaster, you may not be here to tell us about it, so better safe than sorry as they say. We don't want to lose anybody here; make sure it stops before you worry about how it goes.
I have heard that the rear disk brake parking brake cables are difficult. There is no performance gain to rear disk brakes on a 356 unless maybe you're racing. Lots of this stuff comes down to personal preference, which is, in the end, the most important. Good luck. Post pictures of what you come up with.

[Robneal]

I have gone with a 944 master cylinder and the 944 calipers from the same vehicle front and rear. I did this as I know it is a working set-up and therefore there should not be any compatibility problems that you read about with mix and match set-ups. The 944 is a stepped master cylinder in that the front and rears are different diameters and therefore produce different amount of pressure. I have also added a bias valve to the rear set-up as the 944 is a front engined car and the 356 is rear engined. I have not yet driven my car as it is still in the build process but I went through the same deliberations as you and thought I wanted to make it simple and reliable. I am also adding a dual circuit remote brake servo to my set-up to make the braking feel a bit more like a modern car.

[merbesfield]

Has anyone tried one of these? Not sure if it would fit but looked interesting. New offering from Wilwood.



http://www.wilwood.com/MasterCylinders/MasterCylinderProd.aspx?itemno=260-14243-BK