Dual master cylinder upgrade question

[merbesfield]

I have upgraded my 66 to dual MC. Q, the sensor on the original MC had two electrical prongs. The new sensor only has one. Can anyone tell me how to adapt the wires to work? Someone mentioned using one as a ground IIRC, but need more info on how and where if this is the case. Thanks

[John912]

Mark - -thanks for the fuel tank coating recommendation (Sims) -- just picked up the tank today and looks great!

I did mine several years ago, but remember using a new old-style switch mounted either right off the MS like the original using that NLA fitting, or placing the old style switch in a T-fitting nearby, or upgrading to the pedal assembly that contains the switch there. I'm sure you can search this site for more detailed info, or you can search the 912 and 356 sites, plenty of info there also as this is a popular conversion on pre-68 P models.

http://www.912bbs.org/vb/showthread....der+conversion


Remember, you'll need to cut down the actuating rod...

[edmayo]

Mark, the switch on the dual master is for the warning light, vs. the switch on the single master which is the brake light switch. On original dual master cars the brake light switch is on the pedal assembly. I've done this on my 67 and also used a divided master cylinder reservoir that mounted in the original location.

[merbesfield]

Mark, the switch on the dual master is for the warning light, vs. the switch on the single master which is the brake light switch. On original dual master cars the brake light switch is on the pedal assembly. I've done this on my 67 and also used a divided master cylinder reservoir that mounted in the original location.

So that would explain why I have a red idiot light on now on my dash? And does this mean that I don't have Blake lights? That's scary, I drove the car for two hours the other night. Can you give me some more details on what to do? Remember, you are dealing with a guy who has not worked on may Porsches other than doing lots of metal work. Thanks

[edmayo]

Mark, I just added another banjo and used the original pressure style brake light switch. The reservoir is a split type BMW one (compartment needs to have two chambers, other wise advantage of dual circuit M/C is lost) The reservoir is a little larger in diameter so I used a longer bolt with a plastic spacer to tighten against.

[merbesfield]

Very similar to my solution except for the added banjo. So now I guess I have to crack the system one more time. Thanks for idea.

[bfunke]

Why not change out the pedal cluster for a '68 with the switch at the pedal cluster?

[julerb]

John,
What is the "sims" coating on the fuel tank?
Thanks

[John912]

I bought a 911 down south several years ago and was impressed with a red colored coating inside the fuel tank. Needing to get a tank sealed for a 65 911, I looked around in New England and really couldn't find a place, maybe due to environmental laws or maybe I wasn't good at finding a place. I really didn't want to try the Eastwood method. Mark Erbesfield suggested a place outside Atlanta, Sims, and since I was heading to that area I brought the tank with me to take to Sims. It's the same coating that I was familiar with. Not sure what it is, but Clay at Sims says they've tried all sorts of coatings and this is the best. Cost is about $150 to clean tank and coat inside.

http://www.simsradiator.com/chamblee

[julerb]

Thanks, I'll give Sims a call.