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Z31 booster and MC on 240Z


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So I have modified a Z31 dual-diaphragm booster and also bought the MC.

 

-The MC has 2 outlets though for the front brakes.

 

-Can I plug one of the outlets?

 

OR

 

-Do I need to plumb lines separately to the front calipers?

 

Currently I have:

 

Toyota 4 pistons up front

 

Mustang calipers rear

 

Thanks, GI

 

 

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Does your MC look like this?

 

 

post-178-0-93866000-1491269170_thumb.jpg

 

 

What diameter piston does it have?

 

You do know that it is a fast fill MC.  See the bulge on the side.  Has to do with reducing pad drag on the rotors by using "low drag calipers". Google what a "fast fill MC" is. 

 

 

With your particular caliper combination you would need a 15/16in.  to  1in. diameter MC to flow enough fluid.

 

Search the brake and FAQ forums to see if another member has used this MC.

 

Opinion: Why would you do all of the unnecessary plumbing when tried and true bolt on solutions are available.

 

 

 

 

 

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It is a 15/16 bore MC.

 

-If the MC is not recommended, can I use the 280zx MC with Z31 booster.

 

- I have a ZX MC but thought the dual diaphragm would brake the car better since it will have a 3.0 liter in it.

 

-I just need to know if I can plug the one outlet and run the one to the 240Z  prop valve

 

Thanks, GI

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-I read up on the "fast fill MC aka Quick uptake MC".

 

- It does not say you can use  a non-low drag caliper with a fast fill MC.

 

-But, it did say you cannot use low drag caliper with a regular MC.

 

-So my question is:

 

-Can I block off one of the front caliper ports, since it has 2 for the front, and run it with regular calipers?

 

Thanks,

GI

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We did the Z32 mastercylinder and booster, as well as the z32 front and year brakes.. We drove it for about 2500 miles and a couple events.

 

The booster from the z32 over powered the breaks and made them very touchy. Hard to modulate. Had to go back to the stock booster and m/c.

 

Seems the S30 is a lot lighter and does not need the over boost. The z31 may be ok. You can only try and see.

 

The z32 booster is bigger. Do you have a comparison in booster size.

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A one inch Wilwood MC paired with a 280Z booster is what I am using with the Toyota - 240SX combination. Pedal is not stiff. Just feels like normal power brakes.

 

Originally used a 280ZX MC with stock 240Z booster, but the pedal was too stiff.

 

There are several posts here and at ClassicZcars.com describing the 280Z booster swap.

 

 

 

post-178-0-54360600-1491784960_thumb.jpg

Edited by Miles
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So I have the 15/16" ZX MC mated up to the Z31 booster but the BB to MC pin seems a bit short. I usually run .020" clearance but with the original MC spacer/mount I am not even close. Does anyone make a longer rod that is adjustable?

 

Thanks, GI

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-So my question is:

 

-Can I block off one of the front caliper ports, since it has 2 for the front, and run it with regular calipers?

 

Thanks,

GI

It's gotta be two ports just to handle the fluid volume that the calipers use.  Blocking a port should work.  But, as noted, you're kind of reinventing one of many wheels.

post-8864-0-08857200-1492282694_thumb.png

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  • 2 weeks later...
  • 2 weeks later...

I have a 1973 with the wheel well mounted prop valve and then firewall mounted that feeds passenger front brake and rear brakes. I have been able to mount the stock 15/16 ZX booster to the Z31 brake booster. I made new lines for that. I did by an adj. prop valve.

 

-Is the firewall mounted proportioning valve a "damper" device of some sort. I do not know why there would be 2 proportioning valves. I did take it apart and cleaned it (wow was it nasty, both of them actually).

Thanks, GI

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