Stainless/Aluminum Corrosion - PS Pump Bracket

[jgott]

I recently installed my power steering kit and couldn’t get the pump pulley to align very well. So I used some stainless steel washers to dial it in. But then I thought about having stainless against the aluminum block and aluminum pump bracket spacer. Should I be concerned about galvanic corrosion with these touching or am I way overthinking that? I can replace them with aluminum washers if that would be better.

[kirby]

My opinion is that this will not be an issue. Aluminum washers will deform anyway

[jgott]

Thanks.

[Grubester]

I would offer that people in the sailing world know that stainless next to aluminum is quite bad. Galvanic corrosion does happen though it is certainly exacerbated by the salt breeze environment. Still it's a bad arrangement when you look at the electronegativity scale for the two materials.

[kirby]

Galvanic corrosion is very real. In fact cathodes on dam gates, boats etc have been used for years to minimize corrosion. Two materials that are different will always corrode. The question is how much corrosion and how long it will take. The galvanic scale is a great reference but the weight and environment matter.

FWIW all aluminum curtain wall or windows in every skyscraper are aluminum main members with stainless screws. Because of the weight differential there is an acceptable level of corrosion.