Morris Minor Owners Club

Ello chaps,

I have this master cylinder which I bought when Alex and I were trying to exorcise the van's brakes. We trial-fitted it, and tested it, so can't return it, and anyway perhaps it's sensible to keep this one as a spare.

So it's already showing signs of rust after a week, not surprising as I left it with a bit of brake fluid in it, in a non-dry environment; and now I want to clean it out and get it ready to store.

I was assuming I would take out the entrails, wash off the brake fluid, wash out the bore and the reservoir, dry everything off very meticulously, and wrap the thing in waxed paper.

Should I though be smearing any preserving stuff on the bits, eg grease, oil etc? Don't want to damage the seals.

Advice welcome

wibble

Brake fluid shouldn't make it rust. I would simply clean it with fresh brake fluid - and place it in a sealed zip-lok bag with perhaps a sachet of silica gel to absorb any moisture,

No, I wasn't thinking that the brake fluid itself would cause rust, but that brake fluid which has absorbed moisture from the air will do (and has, already )

Thanks for your advice

...then use silicone fluid.

Thanks, Stig, but can't as my system is already full of Dot 4 - and the makers of the servo I'm using don't recommend it for use with their machines, anyway.

It wont do any harm to put a little rubber grease on the seals.

or give it to me as a spare

It's MY spare!

Don't put silicone anywhere near it - if the seals have already 'seen' DOT 4 then when used with silicone fluid they apparently swell up! Don't ask me why - but they do.

Why ?

bmcecosse wrote:Don't put silicone anywhere near it - if the seals have already 'seen' DOT 4 then when used with silicone fluid they apparently swell up! Don't ask me why - but they do.

Mine didn't.

I run my Midget with Silicone fluid, and when I converted it the front disk caliper seals and the clutch slave cylinder seal both swelled enough to make the pistons drag a bit. However, rear drum cylinders and master cylinder seals were fine. That's not to say they didn't swell a bit, but not so much that it caused any sort of problem. Anybody thinking of trying it, you might find that the seals wear a bit more as well, as silicone isn't nearly such a good lubricant as mineral DOT4 is.

Regarding storing your MC - I'd make sure there is NO fluid in it, as DOT4 is hydroscopic (absorbs water from the atmpsphere) and this WILL promote rust. I'm a fan of storing stuff with a wipe of vaseline on it if you can get it to the parts that matter.....

Cheers!

Hence the suggestion of using silica gel to absorb any moisture!

thanks, everyone.

You've picked up exactly on my point, Luxobarge - cheers

Hi Wibble, my suggestion is to use red rubber grease as it is safe on the seals.I always pack this into cylinders upstream of the seals and have used the same wolseley 1500 ones for 15 years as a result having stored them by this method in between.Castrol market this stuff and it is available from an MG supplier

I would worry about using 'Vaseline' which is a petroleum product - and unlikely to be good for rubber seals. The red grease is indeed the correct stuff to use.

thanks, everyone