I wrongly order a front shimano caliper for my TT rig and actually need a rear. Anyone know where I'd get a pivot bolt shown in shimano tech doc's?

Key:
Front (highlighted blue)
Rear (highlighted yellow)

Probably easier to cut the bolt down and put a thread on it.

surely someone sells a Ti version and then I can save weight at the same time (this is WW after all!)

Toronto Cycles sells Ti bolts for Shimano calipers. I have a set of 7800s tuned with them.

If you are not mechanically inclined you will find disassembing and reassembing the calipers less than enjoyable. Especially if you like working brakes. If you're a reasonably good mechanic they're not difficult.

I use small locking pliers to unhook the return spring without scratching the calipers.

For the OP, also take note of item 7 as that is a very small bearing race with micro sized bearings. I took apart a set of DA 7900 to try and find a way to make them expand a tad wider for Zipp Firecrests and was surprised when a bunch of sub ~1mm diameter ball bearings suddenly spilled out and rolled across the workbench.

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