brake clutch master cylinders

[handy andy]

does anyone know what i can do about brake clutch master cylinders rusting
have tried paint but of course as soon as any brake fluid gets near it comes off
were the cylinders originally galvanised and if so where can i get that done
thanks
andy

[mk1]

They were originally either Zinc or Cadmium plated.

You can get them re plated, but this will usually cost more than a new pair. Which would be my option.

M

[66S]

My plater told me Mk1 cans were tin plated. This appears correct and it is interesting to note on an NOS one I have they appear to have been soldered after the plating had been done. I had some replated in tin for my wife's 850 and they do look the part.

Al

[814CWE]

didnt they make the grey zinc plating illegal due to the chemicals in it,,or can we still get this done through"the back door"?

[KA2S4]

66S lives in New Zealand.

Different countries have different laws about what is legal and what might endanger the habitat of the lesser spotted mole-shrew.

Over here you can still get most types of plating done at reasonable prices.

J

[mk1]

The "grey zinc plating" that was made "illegal" was Cadmium, and IT IS NOT ILLEGAL. It is still widely used in the aerospace & military industries due to it's exceptionally good mechanical anti corrosion properties. It is however very difficult for the platers to get the correct certification to use it, as it is a heavy metal neurotoxin.

As a consequence the back street, "tip it down the drain" guys don't do it any more, the only people who do are really big players in the plating field who know how to charge!!!

I am very much open to 66's suggestion that the original metal cans were in fact tin plated, this would make perfect sense.

[handy andy]

thanks for all the feedback
still dont know where to get this done though
i thought zinc plating was galvanising or am i wrong as in road furniture lamp posts etc
shall be in new zealand february so the 665 man may be able to help
long way to do some plating though
wouldnt tin plating be very expensive and bear in mind my cylinders have small pin holes in or would the plating fill that
andy
like the picture WAW what a finish to engine bay and i thought mine was good

[Tim]

Zinc plating is an electroplating process, whereas (hot dip) galvanizing involves dipping the item into molten zinc. It has a similar result, but zinc plating is a lot smoother and brighter than galvanising.

Pinholes in the reservoir can be soldered up, but its fiddly, and you can't always plate over the solder. I was unable to find a plater who could reproduce the finish on my master cylinders so I tinned them with solder (a process known as terne coating) which gives them a less shiny finish than bright zinc or cad plating. It oxidises to a greyish appearance, much like whatever they were originally done with.

One of my reservoirs was badly pinholed, so rather than trying to repair it, I swapped it for one off a spare m/c.



Tim

[1071 S]

Galvanising is indeed zinc plating. And passivated zinc comes in all kinds of colours and is not at all expensive. Plating is cheap.... polishing and finishing to allow the nice smooth surface you need for "chrome" plating is not. A matt looking finish such as that you get with typical galvanising is not dear.

HOWEVER, the process includes an acid bath to clean the surface - and this eats the solder the holds the cylinder together for breakfast....

My cylinders are more than a few years old now - and still look like new - however they are now useless as the filler tubes have become detached on both cylinders. I have not had much luck finding a solderer competent enough to reattach them. Don't know if its the zinc finish but something is preventing the solder from working...

Cheers, Ian

[Tim]

You might need to mechanically remove the plating from around where the necks join on. Both of mine came apart when I was soldering the reservoirs back on to the cylinders after they were re-sleeved, but as they were already tinned it was very simple to solder them back on.

Tim