zoltrixsony

Hi all,
So i have a 1990 JDM S5 turbo. After reading all the stuff on this forum about the brake master cylinder, i have become very confused. especially between the US and JDM versions.
My rx7 is a S5 turbo but doesnt have ABS, different from USDM. and the brake master cylinder has 7/8 written on it. Which is actually the size of the bore for the non-turbos, if im correct.

Well, my question is, is there a difference between the master cylinders in USDM and JDM S5 turbos?
Did all JDM turbos also come with ABS?

j9fd3s

iTrader: (3)

in the US the S5 turbos come fully loaded and only had leather and a CD player as options, so ALL of the USDM S5 T2's have ABS

i know the JDM cars have different option packages, and i'm pretty sure that the lower end models wouldn't have ABS. i would imagine that the GT-Limited had ABS as either standard or an option.

RockLobster

iTrader: (7)

There were only two types of master cylinders in S5 FCs. ABS and non-ABS.

Non-ABS is steel and 7/8" bore and ABS cars had an aluminum 15/16" bore master.

J9fd3s is right, all turbo cars in the US had ABS and the associated larger bore master.

These are not interchangeable.

zoltrixsony

So my BMC has 3 brake line outputs. Looking from the front of the car, 2 on the left (one front, one back) and one on the bottom front. Looking at the non-turbo BMC diagram in the service manual, it has one front right, one front bottom, and one back left.
So Im going to assume the the USDM and JDM ones are different in that aspect!?!?

I guess in the end the BMC in JDM and USDM S5 rx7s arent compatible. Im assuming because of RHD and LHD.

Anyone know where to get a JDM one?????? OR do they still sell rebuild kits for these? Im in australia.

zoltrixsony

Would it be worth buying a new BMC and just replacing the internals with mine?

clokker

iTrader: (2)

I'd just get a 1" bore MC, redo the short lines to the prop valve and be done with it.
End up with better brake feel in the bargain.

In fact, even that is only a half assed upgrade.
Get the larger booster to match the MC (Subarus, Hondas and Nissans are all potential donors) and fix the whole thing at once.

j9fd3s

iTrader: (3)

MAZDA SAVANNA RX-7 | 1989 | GUN M | 116,000 km | details.- Japanese used cars.Goo-net Exchange

not the greatest pic, but master looks like a USDM S5 T2 one, except its iron instead of aluminum, so its different. no ABS either.

RockLobster

iTrader: (7)

Bizarre...never heard of that....could be an aftermarket version of the ABS style master.

j9fd3s

iTrader: (3)

if you look at the other FC's they all have the same one.

eage8

iTrader: (9)

I can't tell which brake booster that is... it looks like the non-abs single stage booster.

ABS has a dual stage booster (which I don't like).

it's probably just a shortened version of the US non-abs BMC due to space issues on that side of the engine bay.

the ABS BMC is shortened like that too because the 2 stage brake booster is thicker.