Preserving brake cylinders

S

stevepm2011

Hero member
Location
Cologne, Germany
G'day all,

My well-developed Laverda spare parts collecting (hoarding ?)  instinct has led to me having a couple of spare brake master cylinders.
These have been overhauled, but briefly used as I experiment with different diameters etc.
This means they have some brake fluid in them, even though I have tried my best to empty them.

I know that brake fluid is hygroscopic, so if I store them like this, they will corrode badly, probably to the point of being unusable in future,.

Any thoughts on what fluids I can use to flush & preserve them?

regards,
Steve


 
Hi Steve,

Thought about that myself.  Usually been reminded when I pull yet another "freshly" overhauled cylinder from a box, only to find it already full of crap.

I think a good flush with brake cleaner to get rid of the brake fluid with a following flush of silicone grease might work for long term storage.  Would obviously require another flushing with cleaner before filling with brake fluid.

piet
 
I've had good luck with filling and bleeding  the cylinders and using a bolt sealed with a crush washer. You can bleed all of the air by tipping the cylinder and gently moving the lever so all the bubbles come out of the little fill side of the cylinder [easier to do than describe] . I had one lying around for about 8 years and it worked perfectly when installed. I suppose it could possibly absorb some moisture while sitting if the bladder under the cap doesn't seal the reservoir  perfectly but plastic wrap between the cap and bladder would fix that.
 
I think as Piet said is the go though you could substitute the brake clean for metho then a light coating of silicon grease and once you have got that far then put in a zip lock bag, expel as much air as you can ( from the bag ) and seal it up.
 
Brett said:
I think as Piet said is the go though you could substitute the brake clean for metho then a light coating of silicon grease and once you have got that far then put in a zip lock bag, expel as much air as you can ( from the bag ) and seal it up, and put them in the freezer.
Click to expand...

Added my two bobs worth.
 
Thanks, all good suggestions.
Wdietz186's idea of leaving it full of fluid but sealed up is an interesting variant!

This is what I am going to try:
Flush cylinder out with alcohol, empty & leave it open for a while to dry.
Give it an internal squirt of silicon lubricant spray (will test this on some old seals first, to be sure the transport medium doesn't cause an issue)
Put it in a zip-lok plastic bag, along with a few sachets of silica gel dessicant, expel as much air as possible and seal.
(silica gel is really cheap on ebay, 100 re-usable sachets cost a few Euros)

Will let you know if it works in a few years' time... :D
 
Thankfully, Brembo seem to have got their shit together regarding rubber compositions.  Only a few years ago, leaving brake fluid in an un-used brake or clutch system would have shagged the seals within a year.  Seems to be on equal terms with jap stuff nowadays.  Perhaps the Kelsey-Hayes/Yamaha influence??

piet
 
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