Just received a fresh master cylinder from mazdatrix but there appears to be a problem. It has all the outputs of the current leaky cylinder plus an extra one that my car apparently does not use. I have an 88 fc, N/A with no abs so i assumed this was the correct one to get.

86-88 Non-turbo

no ABS (Does not include AAS sensor)

After asking a few muffler shops apparently you cant weld cast iron for some reason... My question is are there any ways to safely block the extra valve coming off this master cylinder? Lets assume i don't feel like waiting for shipping again to exchange until i get it right. What are some other options?

 

which one did you order? there is AAS equipped vehicles which covers basically the GXL model(larger than the base master cylinder but not as large as the turbo, the GXL had 4 pot brakes), turbo and then there is base with no AAS and the ABS version which will have a much larger reservoir than any other. the AAS equipped masters have a locking pin screw in the bottom(which could be missing or in the box still) but the only version of master cylinder that i know of with 4 ports is the ABS unit.

http://mazdatrix.com/j-3brake.htm

 

there are 4 different masters for the s4, and 2 for the s5.

for the S4's there is a NON ABS and NON AAS, which fits everything

the S4 GXL, has an AAS sensor in the bottom, so this is #2.

the S4 GXL WITH ABS AND AAS, is #3. this one is 2 line, instead of 3, because of the ABS.

since the TURBO was also available with ABS, there is a NON AAS but WITH ABS master, #4


for the S5 they simplified it, as the AAS drops the brake sensor, and ABS isn't available except on the turbo.

the NA gets one cylinder and the turbo gets another one

you can block off a port, but you need the correct fitting/plug.

 

You need a 10 x 1.00 plug fitting to fill the unused port.
If you have access to a junkyard, such plugs are commonly available on ABS units (check Hondas, I know they have 'em).

 

you forgot the turbo without ABS for s4's

 

Just curious as to were did your master cylinder leak from? Where the master cylinder meets the booster?

 

#1...

 

hmmm interesting, yeah i got the non abs non aas but it had four ports instead of three. I will see if i can hopefully get a good bolt with the correct threading at pull a part's.

 

You don't want a bolt, you want the plug...typically it's an allen head.
The plug will have a recess in the bottom that mimics a brake line flare, so it will seal properly.