Posted by wayneh [172.68.65.177] on Thursday, December 14, 2017 at 23:14:20 :
In Reply to: example of why cast iron pistons are best posted by Kaegi [172.68.142.200] on Thursday, December 14, 2017 at 17:42:45 :
Kaegi: I saw this a few years ago also. My wheel cylinders were only three years old. I believe the dissimilar metal (aluminum and cast iron) works fine if there is absolutely no moisture, but if moisture is present there is a galvanic reaction (like a battery) and you end up with junk parts. On my truck, where there was brake fluid (inside the system) everything was fine, but I had driven the truck in deep water which remained on the outer portion of the cylinder, thanks to the rubber boot. My solution was to put old cast iron pistons in.
Wayne