Datsun Roadster Forum-311s.org

Hello,
I was wondering if a Dual Brake master Cylinder from a 1968 1600 roadster fit my 1966 1600?
Well this help the braking on the current setup?
Thanks..

Now that is an unusual one.
No, it won't be compatible with the brake system in your '66. Plus, the later cars had a pocket cut into the firewall to allow for the lnoger m/c, so a double will probably hit the carbs and possibly the hood.

The dual circuit master cylinder (m/c) means it is looking for 2 brake lines on the car, and your '66 only has one line that feeds over to the junction block, then 2 fronts and one rear departing from the block. (and has one pressure switch, for the S light on the dash).

Dual circuits don't help with stoppping power, they just make you have something left braking wise if there is a fluid pressure loss. (meaning if you have a sudden leak, which is rare, only the fronts OR backs drain and are inop, not a total inop condition).

Single circuit brakes are common, and can be made to work plenty fine.

Simple answer is 'No.' You cannot fit the later dual-reservoir brake master cylinders on the earlier cars without hitting the carbs and/or air cleaner.

ppeters914 wrote:Simple answer is 'No.' You cannot fit the later dual-reservoir brake master cylinders on the earlier cars without hitting the carbs and/or air cleaner.

UNLESS you have an engine swap.

It will fit, but as Furgus said, you will need to run a short new line to connect to the rear brakes and plug the fitting in the connector where you were disconnected the rear line.

Thanks for the commenting.. now I don't have to waste my time taking the other one apart..

fj20spl311 wrote:

ppeters914 wrote:Simple answer is 'No.' You cannot fit the later dual-reservoir brake master cylinders on the earlier cars without hitting the carbs and/or air cleaner.

UNLESS you have an engine swap.

That's why I said simple. I don't think engine swap are simple for most folks.

I know this is an old thread, but couldn’t you swap the air filters out for 2 pod types and have enough room to run the later model dual master cylinder?

No, it’s not the filter that’s the problem. Your brake lines will need to be modified to work with a 2 cylinder system. It can be done, but it’s not a simple mod. Also, as Fergus mentioned earlier there is the possibility of hitting the hood. There are workarounds, but they are not simple either.

Hitting the hood is a major problem. I wonder if anyone has figured out if there is a double plunger master cylinder that will fit in there, without hitting the hood?

My brakes completely failed the other day, like the pedal went to the floor and I rolled through a stop sign. I’m going to try and figure out how to get a dual- plunger in there without hacking the firewall or welding anything, I just figured someone may have already embarked on this journey.

I believe I’ve seen Tilton make firewall systems work on older roadsters. Maybe it was Michael Anderson’s post, not sure

RCMike has a post on Tilton.

I did a Tilton swap from a single circuit master to a dual cylinder master on my '66 low windshield car. Took some firewall modification, a new pedal box, cutting out the old pedal supports, a couple of custom brackets, some doublers, and re-routing the brake lines but it works really well. I also did the Spriso big brake upgrade at the same time.

I'd recommend trying to rig a frt and rear brake master ...to scary on a single , be sure you have a very good E brake.
also the twin cyls pressure izes the rears 1st then frt brakes. harbor freight s double flair tool and a cheap radius bending tool and practice , the double flair has to be just right

I guess my write up wasn’t clear. Definitely two masters, one front, one rear. The pedal has a bias bar built in to allow adjustment front and back. There is a third master for the clutch.