Brake port confusion


Spotter Required
Staff member
Oct 20, 2010
Las Vegas
So, I've been fighting the brakes on my FJ40 with D60 front and 14 bolt rear (3/4 ton D44 disk conversion). Existing master setup is a 79 Dual diaphram booster with a 1" FZJ 80 series master cylinder, but I'm about to add a 86 GM 1 ton master cylinder.

My main question right now is which port goes to the front brakes. I was working this through with @woody and @Lil Rich who both were of the opinion that the rear port goes to the front brakes and the front port (furthest from the firewall) goes to the rear brakes. I was convinced that it was reversed instead, but trust them.

Just recently I found this brake diagram (stolen from

Rear port goes to the rear brakes. Front goes to front.

Reading up on GM junk, there are apparently masters with both designs. I guess I need to go grab the master cylinder I'm gonna use and see which reservoir is larger. I would assume that the disk front circuit would have a larger vol reservoir, which looks to be the rear res on this master.

It seems the answer is "it depends"...
Top Bottom