Brake Caliper Rebuild - stainless pistons vs. aluminum?
#46
Former Vendor
Matching caliper cylinder and piston diameter is subject to mfg tolerance on either parts. Our pistons are precisely ground before receiving chrome plating and final polishing, so their tolerance should be highly accountable.
Expansion rate on stainless steel (RB pistons) is less than 1/2 of aluminum (OE pistons), so a tighter tolerance on SS pistons is warranted.
Source: https://en.wikipedia.org/wiki/Thermal_expansion
The piston movement of a brake pedal's "Apply & Release" is acting upon the pressure seal. So in theory the tighter the tolerance between metal parts (piston & cylinder), the quicker of the action and longer life of the seal will be although the tolerance difference effect here may be negligible.
Expansion rate on stainless steel (RB pistons) is less than 1/2 of aluminum (OE pistons), so a tighter tolerance on SS pistons is warranted.
Source: https://en.wikipedia.org/wiki/Thermal_expansion
The piston movement of a brake pedal's "Apply & Release" is acting upon the pressure seal. So in theory the tighter the tolerance between metal parts (piston & cylinder), the quicker of the action and longer life of the seal will be although the tolerance difference effect here may be negligible.
#47
Rennlist Member
I rebuilt my 996 GT3 calipers with RB stainless steel pistons and there seals and boots, its a dedicated track car and now with 3k track miles and a year later and they're still looking great! No more pucks and those pistons look awesome - very pleased with the quality of the product. I just bought a spare set of calipers and plan to rebuild these with the same.
RB Stainless pistons and rebuilt kit :-)
RB Stainless pistons and rebuilt kit :-)
#48
Rennlist Member
I rebuilt my 996 GT3 calipers with RB stainless steel pistons and there seals and boots, its a dedicated track car and now with 3k track miles and a year later and they're still looking great! No more pucks and those pistons look awesome - very pleased with the quality of the product. I just bought a spare set of calipers and plan to rebuild these with the same.
RB Stainless pistons and rebuilt kit :-)
RB Stainless pistons and rebuilt kit :-)
#49
Rennlist Member
I used the standard RB ones on this set and they have lasted well. For my next set i'm going with the High Temp ones as i use the Permatex grease rather than brake fluid anyway when i'm installing seals etc..
#51
Rennlist Member
Front 42/44mm:
http://www.racingbrake.com/RB-Calipe...-p/st-40bs.htm
Rear 28mm:
http://www.racingbrake.com/RB-Calipe...-p/st-41bs.htm
Blue boots are available as option (over standard black boot)
p.s.
Stoptech caliper components are 100% interchangeable with Brembo.
http://www.racingbrake.com/RB-Calipe...-p/st-40bs.htm
Rear 28mm:
http://www.racingbrake.com/RB-Calipe...-p/st-41bs.htm
Blue boots are available as option (over standard black boot)
p.s.
Stoptech caliper components are 100% interchangeable with Brembo.
thanks!
Mark
#52
Former Vendor
Unfortunately the old Porsche calipers had different construction than the modern ones, so both the pistons and dust boots are not the same except the oil seals.
Due to low demand on those old applications so they are not being made available.
https://www.racingbrake.com/category-s/7552.htm
Due to low demand on those old applications so they are not being made available.
https://www.racingbrake.com/category-s/7552.htm
#53
Rennlist Member
Rebuild with RB pistons and High Temp Boots
Just finished this rebuild with the RB pistons and High Temp Boots - plan to use install these over the winter - love the fit and quality of this product
996 GT3 fronts
996 GT3 rears
996 GT3 fronts
996 GT3 rears
#54
Nordschleife Master
Thread Starter
I'll add a quick note to anybody considering these -
If you have to repair/rebuild your caliper, once you have these pistons - make sure you buy genuine Brembo seals, or the seals sold by RB.
I must've nicked or damaged one of the seals when I rebuilt them this winter (finstalling the RB kit) and found one of the pistons seeping after the first track event I put on the car. I thought I'd save a few bucks, as a local auto parts place could get me a generic piston seal in time to make a weekend (made by Centric)... vs overnighting the official Brembo seal or waiting for a replacement seal direct from RB. The generic seals didn't fit. Too thick! Had to scramble and found a local Porsche Indy shop that had an official Brembo caliper rebuild kit in stock. Had to eat the cost BUT the Brembo seal fit like a champ.
In other words - don't skimp. This is otherwise a super nice kit.
If you have to repair/rebuild your caliper, once you have these pistons - make sure you buy genuine Brembo seals, or the seals sold by RB.
I must've nicked or damaged one of the seals when I rebuilt them this winter (finstalling the RB kit) and found one of the pistons seeping after the first track event I put on the car. I thought I'd save a few bucks, as a local auto parts place could get me a generic piston seal in time to make a weekend (made by Centric)... vs overnighting the official Brembo seal or waiting for a replacement seal direct from RB. The generic seals didn't fit. Too thick! Had to scramble and found a local Porsche Indy shop that had an official Brembo caliper rebuild kit in stock. Had to eat the cost BUT the Brembo seal fit like a champ.
In other words - don't skimp. This is otherwise a super nice kit.
Last edited by User 52121; 09-20-2018 at 07:17 PM.
#55
Any real advantage to the RacingBrake pistons over the StopTech replacements? I figure StopTech is obviously a bigger company that will be around for a while in the event there is an issue or replacement parts will be needed in the future.
#56
Rennlist Member
OP:, I'm not going to read all 55 posts to see what others said, but as an engineer will say this. SS pistons have a substantially lower thermal conductivity than most any aluminum alloy. If you are concerned with brake fade, SS pistons are better. SS pistons are much harder than aluminum, so if not done well designed, there may be an increased risk of cylinder wall scoring with SS pistons. Ideally the pistons' O-ring design prevents any contact of SS pistons with aluminum cylinder walls.
#57
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We hope to be entering the piston business soon...
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High Temp Caliper Rebuild Kits For Brembo Calipers; Caliper Pistons
Ohio Clothing
www.ohioperformancesolutions.com
2007 C4S F77 Aerokit / 2004 E46 M3 / 2018 M3 comp
Ohio Clothing
www.ohioperformancesolutions.com
2007 C4S F77 Aerokit / 2004 E46 M3 / 2018 M3 comp
#58
OP:, I'm not going to read all 55 posts to see what others said, but as an engineer will say this. SS pistons have a substantially lower thermal conductivity than most any aluminum alloy. If you are concerned with brake fade, SS pistons are better. SS pistons are much harder than aluminum, so if not done well designed, there may be an increased risk of cylinder wall scoring with SS pistons. Ideally the pistons' O-ring design prevents any contact of SS pistons with aluminum cylinder walls.
#59
Did you guys consider doming the pistons in the opposite direction to increase the stiffness / reduce the compressibility of the piston structure with brake pressure? AP Racing advertises this as a feature on their caliper piston designs. Just curious if others have considered something similar.
Last edited by Mech33; 09-20-2018 at 01:02 AM.
#60
Technical Guru
Rennlist Member
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