Is it really a good idea to use stainless pistons together with an aluminum caliper? Risk of galvanic corrosion? Thermal expansion of the stainless pistons? Thoughts? Mark, did you machine your own pistons? What material?
Question still stands. I'm aware that the question is probably too advanced for this forum, but I'm still interested in the facts, if anyone has any sensible facts to come up with regarding calipers. Stainless steel thermal expansion is higher than ordinary steel. Maybe it's a problem, maybe it's not a problem.
No risk: there isn't metal-to-metal contact. The pistons are isolated from the calliper by the seal and submerged in bath of brake fluid. Stainless pistons in aluminium calipers isn't something new that we are trying here. I had someone else machine a full set for £80. I polished them to a mirror finish before fitting.
Ferrari only have one option if the pistons are corroded and that is to buy new calipers, they dont sell spare pistons. It does not give Brembo a good name as the pistons are very poor, to be corroding like this- interesting point is they corrode in way of the dust seal and not the oil seal. There is no point in trying to polish the corrosion out as the aluminum comes away in sheets once you try to do so.
Yes, I'm aware of the Brembo Ferrari facts, I've talked to Brembo about it and they didn't want to talk about it. Just had the thoughts about Hill stainless, as it will be more thermal expansion when getting hot (=tough driving, track use etc), if they had that under consideration and compensated for it it any way with other dimensions.
I can't remember if it was the small ones - it possibly was. It was a real game trying to get some of them out. I think I was at 11bar on the air line, and it took several attempts at shutting off & turning on the air abruptly before they would budge. I should imagine that there are quite a few cars out there with the problem.
I did - I will try that next time. I also like the dummy pistons that you had machined to block off the empty bores.
Corvettes have been using aftermarket stainless steel pistons for decades with no problems after the originals corroded. I helped my father fit a set back in the 70s. Lots of clearance and, like somebody said, in a brake fluid bath.
The teflon top hats can be borrowed if you get stuck, saves making them. You just need a handful of clamps from screwfix to hold in place. I also have the m10x1 to 1/8 bsp adaptor to go grease gun to caliper
Since the coefficient of thermal expansion (a in 10−6 K − 1) with aluminum (23.1) is much higher than with steel (11-13), there should be no problems. Aluminum expands more than steel!
I had to replace pistons in GT3 calipers. I think this is where i found them (linking the F430 section) https://racingbrake.com/ferrari-1/
You really don't need to worry with Hills Engineering parts. They are are very experienced, rigorous and meticulous engineering company, if they design a part they will not bring it to market with issues . Their whole ethos is "Better than OEM". I've never fitted any HE parts on my 360 which I've had a problem with, period!
These are the ones which were not corroded, so thats half of the total 20 pistons. Might be useful to someone. Anyone know how to access the classified parts for sale section, cannot find how to submit an add Image Unavailable, Please Login
For now I will see if i can find someone in uk who might be interested as shipping from Isle of Man, to international is making life hard
Out of interest how many of your pistons were corroded or seized. 3 out of 4 of the small 30 mm fronts were buggered, then some of the middle front pistons, the front calipers were worse than the rears. Do you have some pics of the damaged ones
Just FYI, brembo and other brake manufacturers offers stainless piston or titanium. Vented and non. Stainless transfer less heat, and titanium even better. This is very common on race calipers. You can actually order this from brembo for their calipers. Maybe you have to source it from their Motorsport division. The only downside if you do the race/Motorsport route they are not made to accept dust boot. As those melted the first lap you hit the track anyway.
