f80 brake SS piston rebuild DIY?

[SYT_Shadow]

Originally Posted by uncle ben

He got back to me. Says they can make a titanium set for around $700. Pretty pricey, but it would be a big improvement I’m sure.

Just wonder if the money spent between shims, pistons, seals and giro rotors, a person isn’t just better off buying a bbk.

That's a fair point, however, a 'bbk' is a pretty generic term.

Most/all BBKs have rotors of less quality than Giro for example. They do not have Ti pistons. Many times they lack dust boots so they are a liability in winter.

Most of the people that just buy a bbk likely don't need one so they don't run into issues. Others, like myself, end up swapping AP Radicals for BW-Alcons for example because of performance.
I have 7 days on a set of Girodiscs, which is about as long as AP Radical rotors lasted, yet the Girodiscs need to be inspected at 1 inch to see heat checking, much less actual cracking.

[uncle ben]

Apparently stainless steel has worse thermal conductivity than titanium. So titanium pistons would be worse than stainless.

Aluminum 205 w/mk
Titanium 17 w/mk
Stainless 15 w/mk

Obviously titanium is lighter weight, but is that worth triple the price?

[FrankMstein]

Titanium is 40% lighter than steel with greater strength than most 300 series stainless steel alloys. Titanium is more resistant to heat than stainless steel and has a much lower coefficient of thermal expansion. Unlike most steel alloys, titanium is not prone to embrittlement at very low cryogenic temperatures.

[torpeteo]

Originally Posted by jfritz27

So now that I've driven the car around a bit, I've got a somewhat spongy brake pedal I was damn positive after all that fluid flushed (and with a DSC bleed) there were no more bubbles, but I suppose there could be some still hiding. In googling this sounds like this is not entirely uncommon after a rebuild. People talk of things like piston hysteresis; or something else related to fact that grease (instead of brake fluid) was used to lube the seals; all things I'm not sure I fully understand.

Going to drive it through this weekend and see if I get lucky with it firming up on its own, otherwise back to the bleeding with some more fluid. At that point may do a more conventional 2-person pedal bleed. I'll graciously take any other words of wisdom people may have...

I do have the titanium shims as well

Did you ever get this squared away or just attributed towards a break-in period? Wondering if it was just trapped bubbles where tapping the caliper and cyling the piston sometimes helps.

Im on the fence of doing this upgrade. If im going to go with girodiscs and stainless lines it might make sense considering the amount of bleeding that will take place.

[jfritz27]

Originally Posted by torpeteo

Did you ever get this squared away or just attributed towards a break-in period? Wondering if it was just trapped bubbles where tapping the caliper and cyling the piston sometimes helps.

Im on the fence of doing this upgrade. If im going to go with girodiscs and stainless lines it might make sense considering the amount of bleeding that will take place.

That car is gone now, but yes, that feeling faded after a little while, a few weeks IIRC. I'm pretty sure it was the new boots just being stiff (pulling the pistons back a bit) and needing to loosen-up and wear-in. I bled the bejesus out them.

[hC1001]

Originally Posted by uncle ben

Apparently stainless steel has worse thermal conductivity than titanium. So titanium pistons would be worse than stainless.

Aluminum 205 w/mk
Titanium 17 w/mk
Stainless 15 w/mk

Obviously titanium is lighter weight, but is that worth triple the price?

A little late but they use grade 5 titanium alloy and not pure titanium. Grade 5 ti has thermal conductivity of 6.7 W/m-K

[uncle ben]

Originally Posted by hC1001

A little late but they use grade 5 titanium alloy and not pure titanium. Grade 5 ti has thermal conductivity of 6.7 W/m-K

I did not know that. Thanks