Hey guys i wanna put au2 brakes on my au1 I have the suspesion and brake parts ready to go but not sure if I should put the series 2 booster and master cylinder in.

Some people I have spoke with say its not necessary while others say the cruise will not work with series 2 master cylindr I don't see any diffrence with them except I know that the series 2 has a bigger bore for the twin pot callipers so if anyone can give me a few straight answers that would be good.

Cruise control switch runs off the pedal not the cyl.

Best run the series 2 cyl due to being made for those brakes.

Cruise switches are the same on AU I/II/III, I am doing an upgrade to my AU1 XR6 right now and I am leaving the standard AU I booster and m/cyl and see how it goes.
The bracket that houses the brake pedal is different on AU I than the later models, I think it is because of how the booster bolts in? BA was the first to have the Cruise de-activate switch on the brake pedal bracket as BA/BF have an Electrical type cruise in them.

There is another back up switch on the very front of the master cylinder for the cruise control on AU2. It activates if the brakes are pushed all the way in and the other switch doesnt work.



Yep, thats right. The booster has the bolts in different spots. You can swap the pedal boxes over if you drill some holes. I had an AU1 pedal box in my AU2.

So if I fit the au2 master cylinder and not plug in the switch at the front of the cylinder doesn't that mean that my cruise should still work the only reason I wanna fit the bigger master cylinder is that I have heard of people having spongy brakes after doing this conversion as apparently there is not enough line pressure from the sr1 cylinder

The switch at the end of the master cylinder is there to deactivate the cruise when you brake. There is ONLY that switch to perform that function and the Cruise control is the same system using a speed cable hooked to the throttle.

As to the master cylinder, I can't say if the bore IS different but the pistons inside it are the same.

hmm intresting so if the pistons inside are the same how come i have heard of people getting spongy brakes maybe they didn't bleed them properly oh well i've got braided lines to go in anyway so I'll see how we go.