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

[Danlnyc88]

Wanted to share my rebuild on this thread because the info here helped me out a lot.

Long story short, old pistons AND seals were damaged by the idiot who powdercoated my calipers so I said screw him and decided to tackle the rebuild with upgraded pistons myself.

Used a small air compressor with a rubber tip at around 90 PSI. Popping out the pistons was an absolute pain in the ass.

Personally I found that using cut up pieces of old Amazon boxes worked way better than using a piece of wood. The cardboard compresses, minimizing damage and it allows me to stack them together to get the exact tight fit I needed. PLEASE do not stick a finger in between the pistons. Even at 30PSI, the piston closest to the brake line will pop out with EXTREME force.

[FrankMstein]

Danlnyc88 I ended up using cardboard also as wood is not ever the right thickness. The compressor and nozzle method is the best method. Cover your caliper with a rag or your going to get blasted in the face with fluid!

Those look awesome BTW!

[gerri]

Originally Posted by Danlnyc88

Wanted to share my rebuild on this thread because the info here helped me out a lot.

Good job! Can you tell me where did you buy the M lettering?

[Danlnyc88]

Originally Posted by gerri

Good job! Can you tell me where did you buy the M lettering?

It was a reflective one I found from Amazon. They're slightly bigger than OEM though. Have to buy 2 sets for all 4.

Honestly if I had it my way I would have these redone professionally using high temp decals with clear OVER the decal.

If you get yours powdercoated see if they can get you some high temp ones or source some yourself.

Unfortunately, the mine was done poorly.....it is what it is. I'll get them redone eventually.

[jfritz27]

Originally Posted by Danlnyc88

Wanted to share my rebuild on this thread because the info here helped me out a lot.

Long story short, old pistons AND seals were damaged by the idiot who powdercoated my calipers so I said screw him and decided to tackle the rebuild with upgraded pistons myself.

Used a small air compressor with a rubber tip at around 90 PSI. Popping out the pistons was an absolute pain in the ass.

Personally I found that using cut up pieces of old Amazon boxes worked way better than using a piece of wood. The cardboard compresses, minimizing damage and it allows me to stack them together to get the exact tight fit I needed. PLEASE do not stick a finger in between the pistons. Even at 30PSI, the piston closest to the brake line will pop out with EXTREME force.

Lookin' good.... just curious, did it take you forever to get the old boots removed, particularly the anchoring ring that sits in the groove that surrounds the piston bore? I've done this job twice now and both times that was a complete bitch. In both cases though the remainder of the boot was torn away after removing the piston, so I had nothing to pull on. Took forever with pick tools trying to get that ring unseated and out.

[Danlnyc88]

Originally Posted by jfritz27

Lookin' good.... just curious, did it take you forever to get the old boots removed, particularly the anchoring ring that sits in the groove that surrounds the piston bore? I've done this job twice now and both times that was a complete bitch. In both cases though the remainder of the boot was torn away after removing the piston, so I had nothing to pull on. Took forever with pick tools trying to get that ring unseated and out.

Actually no that part was pretty easy for me. I have a pick tool with a 90 degree bend around the tip which helped. All 4 came right out.

[uncle ben]

Anyone have the old pistons around to take a few measurements? Front and rear oem pistons.

[scipy]

Originally Posted by uncle ben

Anyone have the old pistons around to take a few measurements? Front and rear oem pistons.

I just disassembled mine, what do you need?

[chetrickerman]

Originally Posted by scipy

I just disassembled mine, what do you need?

Are the rear pistons 44mm x 32mm?

[uncle ben]

Originally Posted by scipy

I just disassembled mine, what do you need?

The diameter, and the position and size of the seal groove that’s located on the piston. How wide and how deep the seal groove is and how far it is from the outside edge of the piston, as well as the pistons overall length.