[tadaska]

Bought new rear driveshafts and the reluctor ring area is just naked metal. Should I paint them before fitting? I have the "keep it forever" mentality towards my car and the "make it last as long as possible" approach so I do less work on it in the future. But would painting them would actually be beneficial in the long run?

[Chappers 71]

How do they come new? Maybes Google a pick of a new one?

[tadaska]

Originally Posted by Chappers 71

How do they come new? Maybes Google a pick of a new one?

you mean when new on new cars?

[tadaska]

It looks like some are painted, some are only painted underneath the ring not the ring itself. I guess I should better paint main too.

Anyone can advise how to paint them? Best primer and paint etc to make sure the protection lasts as long as possible?

[Silver Streek]

One question that comes to mind is why don't they just zinc plate them after they are machined? It's cheaper than painting and last many more years. They must be unpainted/plated from the factory otherwise they wouldn't rust away as they do.

I've used red oxide primer on bare metal on classic cars and it does a really good job. Last for years without rusting through.

[tadaska]

Originally Posted by Silver Streek

One question that comes to mind is why don't they just zinc plate them after they are machined? It's cheaper than painting and last many more years. They must be unpainted/plated from the factory otherwise they wouldn't rust away as they do.

I've used red oxide primer on bare metal on classic cars and it does a really good job. Last for years without rusting through.

Doesn't zinc plating get eaten away by electrolytes over time? Just something I remember hearing in some video about cars. Don't know much about that stuff.

Also, something I remembered watching, was this video by Jay Leno about rust preventative paint by PRO15. Did a bit of searching and ordered this: https://www.frost.co.uk/blk-por15-starter-kit/

It's supposed to be good for that kind of stuff.

[Silver Streek]

Originally Posted by tadaska

Doesn't zinc plating get eaten away by electrolytes over time? Just something I remember hearing in some video about cars. Don't know much about that stuff.

It will eventually degrade but it can last decades if correctly specified for the specific application. Certainly lasts longer than paint. I work in the rail industry on points systems, we moved away from paint for many of our metal products sitting out in the open years ago. There's equipment out there that's been sat in the tracks for many decades after having all sorts of contaminants spread all over them, including the contents of train toilets and they are still in good condition to this day.

The other plus point for us using zinc plating is the process is fairly well controlled so the plating thickness can be applied so that the parts are still within dimensional tolerance after plating, not so easy with paint. It's also cheaper which I guess would have been the main driver for moving from paint to plating.

[tadaska]

Originally Posted by Silver Streek

It will eventually degrade but it can last decades if correctly specified for the specific application. Certainly lasts longer than paint. I work in the rail industry on points systems, we moved away from paint for many of our metal products sitting out in the open years ago. There's equipment out there that's been sat in the tracks for many decades after having all sorts of contaminants spread all over them, including the contents of train toilets and they are still in good condition to this day.

The other plus point for us using zinc plating is the process is fairly well controlled so the plating thickness can be applied so that the parts are still within dimensional tolerance after plating, not so easy with paint. It's also cheaper which I guess would have been the main driver for moving from paint to plating.

I degreased some of the metal on which the reluctor rings are and sprayed some water on it. The water has now evaporated and there is no sign of rust. Does that mean the metal has been plated or it is not iron?

[Silver Streek]

It's possible it's plated, or it may just have been coated in grease all its life so has not corroded. Given that many seem to blow out with rust I would imagine they are greased rather than plated.

[tadaska]

Originally Posted by Silver Streek

It's possible it's plated, or it may just have been coated in grease all its life so has not corroded. Given that many seem to blow out with rust I would imagine they are greased rather than plated.

But I degreased it with WD-40 and rubbed it with a soapy warm cloth before spraying water on it. Wouldn't that remove any protection the grease was offering?

[Silver Streek]

Depends what steel it is made from, not all steel will show rust straight after being washed. You may not have got ALL the grease off. WD40 is not a degreaser. Some greases especially if they have molybdomen (probably spelt that wrong) in them will chemically bond to the metal surface which helps lubricate the surface to prevent abrasion and offer some protection from surface corrosion.

You need to leave it outside on the rain for a day or so to see if it's raw steel and will start to rust.

[tadaska]

Originally Posted by Silver Streek

Depends what steel it is made from, not all steel will show rust straight after being washed. You may not have got ALL the grease off. WD40 is not a degreaser. Some greases especially if they have molybdomen (probably spelt that wrong) in them will chemically bond to the metal surface which helps lubricate the surface to prevent abrasion and offer some protection from surface corrosion.

You need to leave it outside on the rain for a day or so to see if it's raw steel and will start to rust.

I left a dollop of soaking wet toilet tissue on it over night and it did rust a bit. Only one spot of rust in the middle though, must be like you said - well protected by the oil coating. I'll give it a good clean with acetone and then paint it with that special paint I bought.