Anyone see a difference in these Master Cylinders?

[Ben's Z]

http://extranet.soleniuminc.com/CentricParts/Inquiry/viewDetails.aspx?p=130.42604&a=114329&ic=1&i=1&

http://dormanproducts.com/p-4829-m39277.aspx

Want to move to the 15/16" and to put it mildly I get a steep discount on the second one... However it doesn't "fit"/"catalog" to early ZX's.

[psdenno]

The Dorman M/C catalog link you posted indicates it fits the '77 280Z. Is that not what you want? Sorry, if I'm confused by the application you're seeking.

Dennis

[Reverend]

Is it a trick question? Only difference i see is the size of tanks. Which is a big difference.

[Ben's Z]

I want to be ready for the Toyota 4x4 brake upgrade and have heard that as long as it mounts to the booster and is 15/16" the reservoir size does not matter all that much.

[Dave Patten]

One thing that came up in a discussion with Datsun 510 owners doing MC swaps was the type of braking system. The Z's like the 510's have drum rear brakes. The ZX is disc all the way around.

It appears that all Datsun MC have residual pressure valves built into the bottom of the master. They are captivated by the big hex nut at the brake line connection. The MC for cars with drum rears have a higher residual pressure setting, 10psi +/- on that circuit when compared to a disc brake (front or rear) at a residual pressure of around 2 psi.

There wasn't any noted problems using the all disc brake ZX MC with rear drums but there were a few with issues with using the Z MC with disc rear brakes. Some reported that the higher residual pressure in the rear circuit caused the rear disc brakess to drag. In some cases hard enough that the brakes over heated and expanded to the point that they all but locked up.

I guess what I am saying is if you are changing out your MC make sure the new master matches the rear drum or disc brake system that is in the car. And if not you may need to change out the residual pressure valve on the rear circuit for the right pressure setting, they can be sourced by buying a rebuild kit for the correct MC.

Edited August 31, 2011 by Dave Patten

[Ben's Z]

I am installing 280zx rear disc brakes.

One thing that came up in a discussion with Datsun 510 owners doing MC swaps was the type of braking system. The Z's like the 510's have drum rear brakes. The ZX is disc all the way around.

It appears that all Datsun MC have residual pressure valves built into the bottom of the master. They are captivated by the big hex nut at the brake line connection. The MC for cars with drum rears have a higher residual pressure setting, 10psi +/- on that circuit when compared to a disc brake (front or rear) at a residual pressure of around 2 psi.

There wasn't any noted problems using the all disc brake ZX MC with rear drums but there were a few with issues with using the Z MC with disc rear brakes. Some reported that the higher residual pressure in the rear circuit caused the rear disc brakess to drag. In some cases hard enough that the brakes over heated and expanded to the point that they all but locked up.

I guess what I am saying is if you are changing out your MC make sure the new master matches the rear drum or disc brake system that is in the car. And if not you may need to change out the residual pressure valve on the rear circuit for the right pressure setting, they can be sourced by buying a rebuild kit for the correct MC.