If you're in the market for a good quality used booster from a 8.4" disc car, let me know. I took mine off when rebuilding. Works great no issues. Needs a master cylinder. 

i would go to a dual circuit for safety. if u get a leak on one  other will still work.single circuit was ok in the 60's, bit now things are a lot different. i removed my larger bean can and went with te yellow band mc

 

I wouldn't worry about vented discs.  Maybe in a circuit racer......for a road car, the standard 7.5 inch "S" discs will be fine.  A normal tin tank master cylinder will be fine as well.  

The larger tin tank was fitted to the S to allow the item to be homologated for the Works Team rally cars -driven by Finns using left foor braking.....  They could use up a set of pads and hence drop the fluid level in the "small" tank to a dangerous level in a single stage so needed the extra fluid.  With a road car you just check the fluid level every couple of months..

Having run both with and without the booster I definitely preferr the booster for both road and track...

I use a standard S setup on my 65 Traveller....

Cheers, Ian

It is a 1963. It is a RHD been thinking of going with mini-sport 4 pot vented disk. Looking to get full assemblies as I don't have hubs for disks yet either. Basically building it from scratch!

Eurosteves:

What year is your Traveler?

What year and model were the disks designed for?

Is your car rhd or lhd?

The easiest reply would be to tell you to get the same master cylander and pressure regulator that were on the year and model the disk brakes were for if they are Mini brakes.

The rhd vs lhd is because later year cars had the brake booster as part of the master cylander assembly and mounted on the right side of the car. There was not enough room on the left side.

If the disk brakes are aftermarket, you should contact who sold them to you or see if the maker has a recommended master cylander size.

The last suggestion is start by saying you are installing disk brakes from whatever car they were designed for and ask the board members what master cylander they used.

Russ

Use the regular single circuit Cooper S master cylinder with the larger reservoir, as the disc brake Pistons can displace so much fluid when the pads are worn that it can be an issue. This is the same master cylinder as on the larger ADO16 cars.  A servo is nice, fit it to the front brakes only.

I am in the process of rebuilding a traveller. I am going with disks on the front. I have been trying to figure what master cylinder to go with. Not sure if in should fit a servo or not. Anyone have a suggestions?