Dual Circuit Master Cylinder Kits - Question

[gmund]

My mechanic is close to done with the mechanical restoration of my 58 356A. I ordered the Zims Autotechnik Dual Stage Master Cylinder Kit recently (not yet installed). I was thumbing through the 356 Registry magazine and noticed an advertisement for Klasse's similar kit. I wondered why Klasse was charging $100 more for a similar conversion kit for the disc brake 356 versus the drum brake 356 cars. Zim's Autotechnik kit was the same price for disc or drum. My 356A has had a four wheel disc brake conversion. I called my mechanic to ask if he knew if there would be a difference between the master cylinder for a drum brake 356 versus a disc brake car like mine. He said there were different valves for drum and disc brake cars to regulate the PSI pressure of the returning brake fluid. If I remember correctly, the disc brake cars need 2 PSI of pressure (back pressure may be more accurate) and the drum cars need 10 PSI pressure. He explained this has something to do with the springs in drum brake cars having greater force when you let off the brake pedal and they are returning to a state of "rest". In any event.....my question is does anybody have any experience with either of these dual master cylinder conversion kits? Does anyone know why Zims Autotechnik sells one kit for both drum and discs and says over the phone that it will work with either? I just want to make sure I'm using the best kit and that it's working correctly. Any input would be appreciated. Thanks, Shayne

[call911]

You might try this link:

http://www.356registry.org/Tech/brakes_dual_master_original_reservoir.html

I'm interested in other 356'ers experience as well.

[id10t]

I think Zim's kit uses some more commonly available parts, etc. to do it where the Klasse kit is a custom made setup. I think. Been a few years since I've actually read the 356talk postings (alhtouhg I've got my archive still and am still a Registry member).