Hey guys just wondering if I can use a 720 ute brake master cylinder ony 1200? Currently has a 7/8th master from maddat.

I expect a 720 has a disc front and drum ear. It's always good to try to match the other parts from the same car. You need to at least consider the disk and drum cylinder sizes. 7/8th is thought to be a good master to use when you aren't using a booster.. So I hear. I hope to use a 7/8ths on my white datsun with 1976ish Ute front struts.

Sure you can use it. If it has the right mounting pattern, and the correct pushrod length. Maybe re-do the brake lines to match up.

Regarding diameter, the stock 1200 disc/drum Master Cylinder is 11/16 inch. This provides a good compromise between firmness of pedal and ease of effort -- it doesn't take a body-builder to stop the car. Yet, the pedal is tight when the rear brakes are properly adjusted.

A larger master cylinder (like 7/8") will make the pedal even tighter. But the effort increases. Large diameter master cylinders are typically used with a brake booster.

A smaller master cylinder makes the effort easier, but the pedal travel increases (pedal becomes less tight).

The master cylinder diameter will not change the brake balance (proportioning). Proportioning is controlled by the ratio of front wheel cylinder size to rear wheel cylinder size. So on a 1200 the rear wheel cylinders are different sizes for all-drum 1200 versus disc/drum 1200.

When using larger diameter brake rotors, if the caliper size is the same the pressure required is lessened, so a larger 7/8" master may work fine without a booster.

Yeah I've got a small can booster. I got the 720 master free. The bleed nipples are on the the opposite aswell. They face towards the strut tower.

if it looks like the same style master it will bolt in and the brake lines should line up, providing they have been made to suit the booster, ie master being further forward

also do you realise that the 7/8ths master from maddat probably is a 720 one?

is there any actual reason you want to change other than you got it for free?

The bleed nipples on the master are real close to the intake manifold. Running a sr20de. The nipples on the new one will be facing strut tower so will give an extra 10mm+ clearence.

fair enough, should be a straight swap over, just make sure the booster pushrod length is right for the new master, chances are you wont have to change it but best to check just incase

pretty sure that the 720 master is a 7/8th one. and i never had a problem running a disc/drum master on a disc/disc car either. so there shouldnt be any change in brake performance providing the master is in good condition

Why wouldn't a 13/16 sunny one do the job? 11/16 would be pushing it but seems 7/8 may be overkill unless you go bigger.

I reckon 13/16 might even do 4 pot sumi and bw drum rear end set up.