Hub coatings

[Forssling]

Hi All!
I don't want to do yellow plating on the hubs for the rear. I'm talking about the actual hub and the splined part that goes to the drive shaft.

I would like the steel look on these parts. What should I do?

Just clean, clear coat, silver paint?

And for the front hub. Just carefully soda blast it and clear coat? Or silver paint?

ps. The photos are not my actual parts.

Thanks for any input!

Jörgen Forssling
Göteborg
SWEDEN

[Willem Fick]

The first piece shown in your post is an aluminium part, so can't really be plated. Would respond well to being cleaned properly, either by scrubbing with an aluminium cleaner, by tumbling, or by using a very soft media to blast it with - I'm thinking dry ice... Painting it would not enhance the look, and as it sits in close proximity to your brakes, you will probably find them turning a darker shade of black again in no time.

The following two pieces shown are (ferrous) metal, and can be properly cleaned in a strong caustic soda solution. I guess you could paint them or have them galvanised (yellow if you want the cad plated look), but as they are part of the drivetrain not usually seen, I see no purpose to doing more than just a good cleaning job, which should do a more than adequate job of restoring the "metal look" you are after.

[proffighter]

As the front hubs ar aluminum, I anodized them:

Before:



After:

[chris_seven]

Zinc plating and 'Yellow' Chromate finishing high strength steel parts subjected to fatigue loading isn't the best idea.

Steels with the strength levels used for this application tend to suffer from Hydrogen Embrittlement during electroplating and this can lead to an in-service' failure.

It is possible to 'bake' parts to remove hydrogen from grain boundaries but in absolute terms it is all a bit hit and miss.

If you had developed the plating conditions so that the hydrogen evolution was controlled and then baked for a specific period and then assessed the resulting parts the practice would work and is used on a routine basis.

To zinc plate parts made of a steel that has similar properties to Grade 8.8 bolts or stronger and then bake in an relatively uncontrolled manner isn't the may not always work.

Most of the time it may be OK but if a short crack does occur due to the hydrogen it could well propagate and cause a catastrophic failure.

If you just want to tidy them up I would use a 'Black Oxide' finish. It isn't really corrosion resistant but has a decent appearance.

[Forssling]

Thanks all for your input. I have no intention of plating either parts. From what you say painting (clear) won't do the job so I just leave them natural.

Cheers,
Jörgen

[Evans, Marv]

This may be the cheap way to go & I don't really know how it holds up long term, but on parts like these I clean them (mask if necessary) and spray with Rustoleum Crystal Clear Enamel. At least it fills in pits & pores & cleans up a bit with just hosing it off.

[Forssling]

Originally Posted by Evans, Marv

This may be the cheap way to go & I don't really know how it holds up long term, but on parts like these I clean them (mask if necessary) and spray with Rustoleum Crystal Clear Enamel. At least it fills in pits & pores & cleans up a bit with just hosing it off.

That might be something to look at. It can't do any harm, could it?

//Jörgen

[mskala]

I had a set of front hubs which where deeply pitted wherever the anodizing was not intact. I assume from brake dust and heat maybe? I would not run bare aluminum for long-term.

[Forssling]

Originally Posted by mskala

I had a set of front hubs which where deeply pitted wherever the anodizing was not intact. I assume from brake dust and heat maybe? I would not run bare aluminum for long-term.

I hear you. I'll look into what options I have for anodizing aluminium here in Sweden. From what I understand, for anodizing, I have to remove the bolts from the hubs which I would like to avoid.

//Jörgen

[Willem Fick]

Yes, you will have to remove those unfortunately.

[Shaun @ Tru6]

Originally Posted by mskala

I had a set of front hubs which where deeply pitted wherever the anodizing was not intact. I assume from brake dust and heat maybe? I would not run bare aluminum for long-term.

The hubs weren't anodized from the factory though it is a good idea.

Here's what we did for a customer's long distance restoration. We removed the studs with a shop press and those were plated in black phosphate. Hubs were cleaned and tumbled and then tumbled-polished which micro-peens the surface slowing down oxidation. Studs pressed back in, then all new bearings. Bearing caps were plated in grey phosphate to as new.

[Forssling]

Looks good Tru6!

//Jörgen

[Ferrino]

I'm cleaning up my rear hubs and was wondering if the hub face can be coated with something very thin, such as ceramic coating (typically 0.001" build)?

[911pcars]

Originally Posted by Ferrino

I'm cleaning up my rear hubs and was wondering if the hub face can be coated with something very thin, such as ceramic coating (typically 0.001" build)?

Ceramic coating would be a good option as the coating surface is thin, robust, corrosion resistant and impervious to typical automotive solvents/greases/brake fluid. Various color options are also available (aluminum, gray, titanium, etc.). I would mask the splines and remove the pressed-in lug bolts before applying the coating.

Maybe plan on batch painting as ceramic coating prep, material and application costs are currently higher than other processes.

Sherwood