[smdubovsky]

I'm putting a set of 993 calipers on the 911 using 930 rotors. I refused to pay $250 for the front adapters, so I made my own. After some carefull measuring, scribing, and a little guess work the first crack came out spot on (well, within 0.5mm). I've made myself a dimensioned solid edge cad drawing for future reference. I made the other side after work today and counterbored pockets for the strut bolts. I'll machine some weight out of them before its all over with...

[smdubovsky]

The rears are trickier. 993 rotors are 24mm wide. 930 rotors are 28mm wide. The "normal" thing to do is to machine the little tabs off inside the caliper throat so that the wider rotor fits. With this approach, every time you change pads you have to sand off 2mm from each pad That seemed like a real PITA long term so I simply widened the calipers. I bought a 4mm plate of 7075 (its harder than 6061) and made bridge spacers. You can recurve the factory crossover line to still work - though its close (I was originally planning on making new ones.) I still need to slice the metal 'pad box' part and widen it. Nothing a little welding can't take care of. (Sorry there aren't more pics, the camera batteries are all dead.)

I also need to relocate the mounting holes to 3". Most people weld them up and redrill. Since the caliper will also have to move inboard 2mm to accommodate 1/2 the spacer, Im thinking of machining the tabs completely off and making an adapter block like the fronts (VCI does this)

[Jazzbass]

Originally Posted by smdubovsky

The rears are trickier. 993 rotors are 24mm wide. 930 rotors are 28mm wide. The "normal" thing to do is to machine the little tabs off inside the caliper throat so that the wider rotor fits. With this approach, every time you change pads you have to sand off 2mm from each pad

No you don't. At least, I don't with the 964 calipers that are on the rear of my car. I'm pretty sure they're the same dimensions as the 993 caliper. New pads drop right in - no sanding. And yes, I'm using 930 rotors. The nice part is you don't have to machine off the tabs, either, as the caliper is centered over the rotor using the old fill-and-drill technique. Don't have to make new cross-over tubes, either.

Nice machining work. I want a vertical mill, too. Where'd you get the bar stock?

[smdubovsky]

Originally Posted by edevinney

Very nicely done! Are there seals where the bridge spacers go? And on the subject of those, did you use the 4mm stock as-is, or did you have to mill it to have flat, parallel faces?

No seals. The caliper halves are joined w/ a crossover tube which makes it easier. I used the 4mm as-is. It mic'ed very flat across the ~1x2" pieces you need.

Originally Posted by Jazzbass

No you don't. At least, I don't with the 964 calipers that are on the rear of my car. I'm pretty sure they're the same dimensions as the 993 caliper. New pads drop right in - no sanding. And yes, I'm using 930 rotors. The nice part is you don't have to machine off the tabs, either, as the caliper is centered over the rotor using the old fill-and-drill technique. Don't have to make new cross-over tubes, either.

Nice machining work. I want a vertical mill, too. Where'd you get the bar stock?

A 993 rear caliper is 2x the size of a 964 Not really, but it is the same size as a 964 front. (Insert gurly man comment here.) Do you have 964 turbo rears?

The 993 rear caliper throat measures 26.7mm between the pin/protrusions. A 28mm rotor doesn't fit. You HAVE to do something about it. Everyone on pelican says you have to sand pads (though there are pagids(?) that come in a thinner version.) I could do the fill & drill technique and add 2mm spacer washers. VCI does that for their 930->911 caliper conversion. I have a mill, so just cutting them completely off and using a radial style adapter block is sexier I haven't gotten up the courage to do it yet though...

I've had the bar for a while. Prob came from www.onlinemetals.com

Edit: Just went and double checked the caliper. The ID of the caliper housing is 63.1mm minus 2 new porterfield pads @ 35.1 = exactly 28mm. Now, the pistons/seals can't retract 100% into the caliper so you need to shave pads or widen the caliper to actually fit a 28mm rotor.

Edit2: Total brainfade! The 964 came w/ two version of rears. I was only thinking the early small one. There is a later one that is the same size as the 993 rear. It uses the same pad F&R right?

[Jazzbass]

I have the late 964 4 piston rears - same as the 993s:





Takes the same pad as the front - the std 930 size pad. The throat is machined to go over the 28mm rotor.

Originally Posted by smdubovsky

Edit: Just went and double checked the caliper. The ID of the caliper housing is 63.1mm minus 2 new porterfield pads @ 35.1 = exactly 28mm. Now, the pistons/seals can't retract 100% into the caliper so you need to shave pads or widen the caliper to actually fit a 28mm rotor.

OK, now you have me wondering about this. It's been over a year since I put these on, and I honestly don't remember sanding the pads. But I also don't remember what I had for lunch today, so take that for what it's worth. I've only been through one set of pads so far, and it's time for a new set. We'll see if I have to sand to get the new pads (Hawk DTC60s) in.



What you really need is a set of 965 calipers

[smdubovsky]

Originally Posted by Jazzbass

I have the late 964 4 piston rears ... The throat is machined to go over the 28mm rotor.

Ok, that makes sense.

Originally Posted by Jazzbass

What you really need is a set of 965 calipers

Yeah, thats essentially what Im turning them into Those don't come up for sale very often.

[edevinney]

Very nicely done! Are there seals where the bridge spacers go? And on the subject of those, did you use the 4mm stock as-is, or did you have to mill it to have flat, parallel faces?

[Landjet]

Anyone want to buy a complete set of 996TT brakes? PM me. $900.

[William Miller]

I had to do some machining on the throats of mine for clearance and I do have to sand the pads. I made a holder / gauge block to do this on the belt sander. It takes about 5 minutes, but stil a pain. Plus I bet I'm getting some belt material embedded in the pad too. I WANT a set of "Steve's Spacers!


Great Job!
My fronts are willwood rotors. I replaced the light version that came with the kit aith their heavier version. They are really smooth now, but, I've yet to have the car on the track.

[smdubovsky]

Here Im widening the endplates. These hold both the pads in place (the 'L' at the bottom) and the top spring that keeps them in.

Bill, I don't think you should widen the caliper once you ground the tabs (and the 'L') off. You risk the pads shifting or falling though when they get low.