Replace Aluminum Screws with Stainless Steel?

[aesalazar]

Hi guys.

I am tearing down my newly rediscovered YZ10. As I do it I noticed that most, if not all, of the screws going into the front and rear magnesium bulkheads are Aluminum. Interesting choice but I would rather just replace all of them with Stainless Steel which would be more durable (most of the aluminum screws are stripped to varying extents).

But I am wondering why they would use Al as the material in the first place. Is it purely for weight? Seems kind of silly, cant image it making that much of a difference.

Or is it because Steel screws can react with the magnesium. I didnt think it would especially since the main bearing for the differential are stainless but figured I would check first. What really gave me concern is that the rods holding in the lower A-Arms (looks like steel) are actually seized up with the bulkheads when trying to pull them out.

Ernie

[jwscab]

You can look at a galvanic chart to see what metals are good to work together. In the case of magnesium, being very reactive one of the best fasteners would be zinc plated steel, then cadmium, then aluminum alloys. Anodized aluminum fasteners would work great as the oxidation layer would really slow down a galvanic reaction. Stainless steel can vary quite a bit on the chart so would actually be not a good idea.

My suggestion would be to use the stock type fasteners, or good anodized replacements from fastener express. (100 degree taper).

[aesalazar]

Thanks @jwscab. That's what I thought. My chemistry/metallurgy is pretty rusty from college but I remember magnesium being particularly reactive. Really wish they used something else.

Ernie