After spending two days chasing parts to replace a surge brake master cyl. and the back up solenoid which was rusted internally from brake fluid that does and will absorb moisture. This thought occurred to me, why aren't the M/C's made from cast aluminum? Makes zero sense not to, but 150 dollars later could have bought more gas and beer. What do guys say? Trailer is always inside so weather and exposure is not the issue.

I'm not seeing aluminum being used for hydraulics. Could use it for the reservoir but then need other materials for the hydraulic parts. Could keep it working if we just bleed/cycle thru some fluid every so often, but I like you don't think of it much until a problem comes

I agree with the replacing and bleeding fluid more frequently, simply because no one makes the aluminum replacement. My thinking was all of the late automotive stuff does use aluminum castings for "hydraulics" so it must work.

No argument relative to better overall braking with EOH, but the amount I trailer now has changed dramatically. One trip from KC to LOTO in the spring and a return from LOTO to KC in the fall. Guess I"ll live with the periodic maintenance.