Shorter 7/8" master cylinder for b210/180b booster

[jeremiahnz]

Hi, just progressing my brake upgrade a bit and need to source a 7/8" (minimum) master for the rx7 4 pots. I was going to order the 7/8" master cylinder from maddat (http://www.maddat.com.au/brake-parts.php" onclick="window.open(this.href);return false; Product No - MC7/8) which I presume is a 280z replacement item.

It would be good if I could get something a bit more compact as this would sit very close to the super charger and I would like a reasonable amount of clearance to allow for engine movement.

Is there a 7/8" or 15/16" master cylinder that anyone knows of with the same bolt pattern as needed to attach to a b210/180b booster?

[jeremiahnz]

Still looking for master cylinder options as the datsun masters (i.e. 180b) have the bleed nipples in a position that could foul on the supercharger.

I have found some info that suggests that some Mazda master cylinders (i.e. rx7 s3, b series utes) are 7/8th bore (or greater), and share the same vertical bolt pattern with 60mm spacing as the datsuns have and that the 180b booster I have shares.

Has anyone ever tried one the Mazda brake master cylinders? Keen to hear if they do work before I spend $$.

Cheers

[brocky41]

can you take a couple of pics of what you have and with it fitted to the car - i can check at work, BNT, as all the guys in our branch love to hunt that kind of stuff out.

Cheers
Brock

[jeremiahnz]

Cheers Brock,

Here are a couple of pics.

The first one shows how close the bleeder nipples are to the supercharger, and whilst I understand I can probably get shorter bleeders, I want quite a bit of clearance as I don't want to take risks with the brakes.

photo.JPG

This pic just shows the bolt pattern the master cylinder.

photo (1).JPG

The current master cylinder is 3/4 bore, so I need to change it anyway, and I understand the 7/8 bore from the datsuns that would fit this (i.e. 180b or 280z I think) are pretty much the same master but with a 7/8" bore so it still has the same issue.

I found some stuff that suggested some Mazda master cylinders from around the early 80's (possible S3 RX7, or B series ute) have a 7/8" bore, have the bleed nipples on the other side, and have a 60mm vertical spaced bolt pattern and will therefore bolt up to the Datsun booster. Also they are dual circuit which I want (original 411 master isn't).

I'd also be happy with a 15/16" bore, as it is running RX7 4 pots up from and disc brakes in the rear. I have a Wilwood adjustable brake block (replaces the standard dist block plus has the front/rear bias adjust).

Thanks again.

Jeremy

[Godzilladat]

The 280z stuff from the USA should have the bleed nipples on the other side than your pic to suit a LHD. For more clearance you can get to the wreckers and steal the fluid caps and remote reservoir off a nissan urvan.

Remote reservoir

[Datto_610]

A 15/16 M/c from a 280ZX would be perfect as they have bleed nipples on the other side. 180B's are 3/4 not 7/8. 620 utes and R30 skylines are 7/8 I think but nipples might still be close to your supercharger. I do have a 280ZX m/c but pretty sure Bart has dibbs on it. However if you want to test fit one for the mean time I would be willing to send it up for test purposes as I doubt Bart will be using it anytime soon!

[jeremiahnz]

Thanks for that info. Do the 280zx have a vertical bolt pattern? I was under the impression they had a horizontal bolt pattern?

[Datto_610]

The earlier ones do. I have fitted it up to my 180b booster before but the nipples fouled on my strut tower. Now have a 7/8 from a 720 with the nipples on the right side (well for me anyway) also running rx7 4 pots

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[jeremiahnz]

Awesome. Where did you order your 280zx master from? How do you find your brake setup?

[Datto_610]

My 280 m/c is second hand would've got it rebuilt if I was going to use it. Haven't tested my brakes yet not quite at that point!

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