Dual circuit brake conversion

[Spit Nolan]

Hi, Wanting to convert my 67 to Dual circuit brakes as a lot of the single circuit bits are missing anyway.

Got a dual circuit master cylinder with a brake light switch on its way like below



I was hoping to hide a reservoir in the smugglers chest, rather than installing a later 68 on version and the hard tubings from it.

My question is, can I get something like the two plastic tube fittings to connect to the Porsche master cylinder, so I can run soft lines through to smugglers chest. Or do I have to get the hard lines to be able to push into the rubbers on the top of the cylinder?


Something like these?

Or do I need to find 11 and 12 from this diagram?

Cheers Spit

[SeanP]

The switch on that master cylinder is not a brake light switch. It’s a brake warning light switch that needs to be manually reset. The brake light switch is mounted on the peddle assembly. You will also need a dual circuit plunger on the brake peddle.
You can buy the rubbers and the pipes to go into the master cylinder from the Reservoir from all the usual suspects. They are short and the rest of the run is in flexible brake pipe as that part of the system is not under pressure.

[Spit Nolan]

Ah ok thank you, can just leave that disconnected and put a t piece in and continue to use the fluid switch I suppose. Not been able to find the pushrod yet, my single circuit one is missing so not even like I can cut that down. Will get the part number out and head to the Porsche parts department haha

[SeanP]

Or buy a latter pedal assembly! And get the brake light switch and push rod

[Ollie]

912bbs have few threads on dual circuit conversions.

[Spit Nolan]

Cheers

I managed to get a couple of the plastic fittings from a beetle, they fit perfect! So dual circuit reservoir and some hose and it’s in, I’m still looking for a dual circuit push rod, I don’t really want to change the whole pedal assembly for a later light switch, so just putting a t piece in for the hydraulic switch.
If anyone has a push rod let me know

[Alan @ CanfordClassics]

I make new ones. Drop the office a call and say I said to phone.
Alan
Canford Classics

[Spit Nolan]

Thanks Alan, I’ll get in touch

[IanM]

Is the master cylinder with the switch (warning function) just for USA-spec cars? What year did it start?

I saw a RHD longhood 911 LWB (unrestored) with the USA-type master cylinder, so I'm a little confused.

Is the warning function for brake pad wear? Does it warn by a light on the dash or a buzzer?

TIA.

[PeterK]

Brake warning is via a multi-purpose / light unit in the dash.

Rather than mess about modifying the pedal box, just first a t-piece into each circuit and use a hydraulic brake light switch.

[Timo]

I’ve recently replaced the master cylinder and lines to the reservoir on my car, I bought a reel of the correct type flexi hose, but only needed two short sections from the hard lines to the reservoir. If you end up needing some flexi to the reservoir I’m happy to chuck you a bit in the post, just let me know.

[IanM]

Brake warning is via a multi-purpose / light unit in the dash.

Rather than mess about modifying the pedal box, just first a t-piece into each circuit and use a hydraulic brake light switch.

Thanks but I was asking about the switch (warning function) on the master cylinder itself, not the one at the pedal.

What type of master cylinder did RHD longhood LWB 911 cars have? With or without warning function?

[Timo]

I was under the impression the brake warning switch was US spec only, happy to be corrected.

[IanM]

Thanks.