Hello,

I was wonder if using a S5 brake booster in a S4 is possible if both use Non ABS non Adjustable.

I think the master cylinder has two outputs on each version.

I'd like to use a S5 brake booster on a S4 without changing the master cylinder. . .. I know the brake booster is larger in Diameter for a S5 "hard suspension" booster, but as long as the master cylinder bolts up everything should be good right?

 

Using the booster part number FB05-43-800D, fitment w/o turbo:
1991 Mazda RX-7 Base, Convertible 1.3L R2 - Gas
1990 Mazda RX-7 Convertible, GTU, GTUs, GXL, GXL 2+2 1.3L R2 - Gas
1989 Mazda RX-7 Convertible, GTU, GTUs, GXL, GXL 2+2
1988 Mazda RX-7 10th Anniversary, Convertible, GTU, GXL, GXL 2+2, SE, SE 2+2
1987 Mazda RX-7 Base, Base 2+2, GXL, GXL 2+2, LX, LX 2+2, Sport
1986 Mazda RX-7 Base, GXL

 

Hey, Thanks for your reply.

I think that number is for the booster and cylinder attached. But your reply made me think down that part number and the variants.

I assume the tube should be there even though it is not shown in the diagram.

MASTER VACUUM. Power Brake Booster.

Part Number: FB0143800C
Supersession(s): FB01-43-800C; FB0143800Normal Ride Suspension. Normal Suspension. Power Brake Booster.



Fits RX-7 (1986 - 1989)

Mazda RX-7 1.3L 2 cylinder A/T Base 2+2 Coupe 1987
Mazda RX-7 1.3L 2 cylinder A/T Base Coupe 1986, 1987
Mazda RX-7 1.3L 2 cylinder A/T Convertible Convertible 1989
Mazda RX-7 1.3L 2 cylinder A/T GTU Coupe 1989
Mazda RX-7 1.3L 2 cylinder A/T GTUs Coupe 1989
Mazda RX-7 1.3L 2 cylinder A/T GXL 2+2 Coupe 1987, 1988, 1989
Mazda RX-7 1.3L 2 cylinder A/T GXL Coupe 1986, 1987, 1988, 1989
Mazda RX-7 1.3L 2 cylinder A/T LX 2+2 Coupe 1987
Mazda RX-7 1.3L 2 cylinder A/T LX Coupe 1987
Mazda RX-7 1.3L 2 cylinder A/T SE 2+2 Coupe 1988
Mazda RX-7 1.3L 2 cylinder A/T SE Coupe 1988
Mazda RX-7 1.3L 2 cylinder M/T 10th Anniversary Coupe 1988
Mazda RX-7 1.3L 2 cylinder M/T Base 2+2 Coupe 1987
Mazda RX-7 1.3L 2 cylinder M/T Base Coupe 1986, 1987 . . .This is mine
Mazda RX-7 1.3L 2 cylinder M/T Convertible Convertible 1989
Mazda RX-7 1.3L 2 cylinder M/T GTU Coupe 1988, 1989
Mazda RX-7 1.3L 2 cylinder M/T GTUs Coupe 1989
Mazda RX-7 1.3L 2 cylinder M/T GXL 2+2 Coupe 1987, 1988, 1989
Mazda RX-7 1.3L 2 cylinder M/T GXL Coupe 1986, 1987, 1988, 1989
Mazda RX-7 1.3L 2 cylinder M/T LX 2+2 Coupe 1987
Mazda RX-7 1.3L 2 cylinder M/T LX Coupe 1987
Mazda RX-7 1.3L 2 cylinder M/T SE 2+2 Coupe 1988
Mazda RX-7 1.3L 2 cylinder M/T SE Coupe 1988
Mazda RX-7 1.3L 2 cylinder M/T Sport Coupe 1987
Mazda RX-7 1.3L 2 cylinder M/T Turbo Coupe 1986, 1987, 1988, 1989


Apparently you can still get one brand new if you wanna pay for it. .. .I am gonna try the used market first. .. I'm already too deep as it is.

https://www.atlantamazdaparts.com/p/...B0143800C.html

 

^Not to prolong the topic, but the above states for normal ride, normal suspension, but included are the base,active suspension/turbo models that have different suspensions.
IDK?
Try used, plenty available:
www.car-part.com

 

I think the list implies that if you had a 4 or 5 lug model S4, you could have the same brake booster up to 89. But if you had a 5 lug with ABS or active suspension, you had a different brake booster.

Apparently 90 and 91's were different as I assume ABS or some other option became standard requiring a different brake booster.

I could be wrong about that, but the list points me in that direction.. . .Assuming the list is correct of course.

Parts geek had a remfg unit so I bought that. . .. But that could go wrong. Two days ago I thought Rock Auto had one, but that order was canceled because of "inventory error" by them. We'll see if parts geek actually delivers the right part without canceling it.

RL

 

in the USA there are basically 2 boosters.
FB05-43-800D, which fits everything except the 89-91 turbo, and FC06-43-800A which is 89-91 turbo.

the FC06-43-800A uses a different master cylinder, its bigger and has a different mounting, so they need to be a matched pair (or you can run the FD/929 masters)

 

Knew at some point we'd draw out one of the our resident experts.