Rear Brake Upgrade

[Duk]

Inline with a million other changes and jobs I'm doing, I started doing a rear brake upgrade ages ago based on Series 4/5 Mazda RX7 Turbo calipers and Wilwood 10.75" vented rotors. 1 part of the job that I was loathing to do was to get accurate measurements to actually make the adapter mount. But I finally got off my arse and made the dummy mount so I could get dimensions.

The big problems are that (for some reason) the calipers used 2 bleed nipples. The lower 1 gets in the way and it and its boss that was part of the caliper body, were removed. So I'll have to weld up that bleed hole.
The other negatives are actually getting to the top bleed nipple and the nipple isn't right at the top when the TA is level. So when I get the flexible brake line that goes to the T piece made, it'll be made longer than original so I can allow the TA to hang down at the back (front mounts, tail shaft and gear selector disconnected of course). This will give access to the nipples and help them to be the highest point on the calipers.

The nice part about about the Mazda calipers is that they have good, reliable, self adjusting hand brake mechanisms, shed load more pad area and plenty of after market pads available for them, too. They also give much more clearance where the exhaust goes over the driver's side drive shaft, so getting a 3" pipe through there will be much easier.
The hand brake mechanism will be a challenge, but I reckon I've got it mentally sorted. 'Ehh, mental, that is.'  

[ARQ164 Shane]

hmm ,are the rotors( Wilwood 10.75" vented rotors) off the shelf ?
or a custom job?
cheer

[Duk]

Off the shelf.

[Duk]

Some days I marvel in my own stupidity (sort of). When doing this upgrade I initially mad the central hub from an old disc, but that didn't allow enough offset. Then I made 2 of the hubs in the 1st picture. Once I had measured and made the caliper mounts I then realised that I hadn't allowed for the sliding of the calipers as the pads wear. Obviously not an issue with the opposed piston calipers but a definite need for the Mazda calipers.

Live and learn and learn and learn and lea............... 

[ARQ164 Shane]

hi guys,
Do you know that you can make the old calipers fit vent rotor.
BMW "old school boat anchor "4 pot calipers have space that should fit your alfa rear calipers you will need the bolts
too .

[Duk]

BMW "old school boat anchor "4 pot calipers have space that should fit your alfa rear calipers you will need the bolts too

That is interesting! Which model of BMW with 4 piston (where the term 'pot' comes from I'll never know) are you referring to, Alphie?
I thought maybe you meant ye olde Volvo cast iron calipers  . They're pretty common (got some myself at the pointy end).

[ARQ164 Shane]

duk, just go to u-pull-it and look you will fine about 5 .
ye very oldy ones, you know that one with the big 6cyc .