Plating Rear Hub a Bad Idea?

[frankc]

I am in the process of replacing my rear wheel bearings so I have the stub axles & wheel hubs out of the trailing arms. I also plan to be dropping off a couple of boxes of parts to be yellow zinc plated this week, and thought about adding the hubs to the box of parts since there will be no additional charge and will add a bit of corrosion protection.

My concern is that, given the already tight tolerance of the hub and wheel bearing, will the addition of the zinc plating (albeit very thin) make it more difficult to press in the hub?

[Eric_Shea]

Not a big deal. If your concerned you can wrap some 600 grit around the base and clean off the plating before you pull them into the bearing.

[Ferrino]

Did you end up getting the hubs plated? I'm also accumulating parts for a large plating batch and am wondering about the suitability of the following parts for plating:

rear wheel hubs
tranny input flange
clutch fork

I've read that care needs to be taken when zinc plating hardened steels, due to the potential for hydrogen embrittlement. I believe a baking procedure is necessary after plating?

[Steve@Rennsport]

I would never plate hubs for any reason due to hydrogen embrittlement which makes them much more prone to fracture, even if baked (stress relief).

[stownsen914]

Interesting about hydrogen embrittlement being caused by plating. Agreed that in that case stress relief would not help - from research I did before tackling welding chromoly, stress relieving does not address hydrogen embrittlement. Once that happens, it's done.

Does hydrogen embrittlement happen when chrome plating too? I understand chrome plating can be a good way to bring a crankshaft journal back to standard, but not if the plating process causes hydrogen embrittlement!

[Ferrino]

What would be a good alternative finish for the hubs (on the non-mating surfaces)? Bead-blast followed with Gibbs? Paint?

[Iciclehead]

This whole hydrogen embrittlement thing that comes up every time plating is discussed really has me in a quandary.

I have heard and read and definitely have concerns, but when I go to my plater who does all sorts of things for industrial uses, oil and gas uses and such.....frequently stressed components...he knows about hydrogen embrittlement and says it is not an issue at automotive loadings and it really does not appreciably harden to any significant depth. He was willing to warranty any part I had him plate (zinc dichromate) against breakage or shattering due to embrittlement. Now, how I would prove it is a whole other question, but I guess I wonder this.

Does anyone have any examples of a plated part in an automotive use that has failed where the failure has been traced to the plating process?

Having said that, my new hubs are plated....I guess I will take my chances.

Dennis

[bpu699]

Why not just powdercoat...

I did some replating of parts on a prior car... within a couple years they don't look so hot. If you ever see salt, it will be a couple days before they start to oxidize...

CAD plating lasted... Yellow Zinc, not so much. The suspension will get wet, and might see salt. Did you consider black powdercoat?

[frankc]

Originally Posted by Ferrino

Did you end up getting the hubs plated? I'm also accumulating parts for a large plating batch and am wondering about the suitability of the following parts for plating:

rear wheel hubs
tranny input flange
clutch fork

I've read that care needs to be taken when zinc plating hardened steels, due to the potential for hydrogen embrittlement. I believe a baking procedure is necessary after plating?

Yes, I did have the hubs plated (and the gearbox output flanges from your list), and there was no issue pulling them into the bearings.

I've had the car on the road since March with about 1000 miles on it so far, and so far all is good . In case anyone is wondering, this is not a track car.

Here's a photo of the plated parts: