why did my master cylinder...

[mike reeh]

.... go dry and some fuzzy chunky stuff grew in the place of the fluid? anyone seen this happen? Ive inherited an '83 minnie winnie on a chevy C30 chassis...

its got a small block with hydroboost brakes... well the master cylinder is bone dry and there seems to be some sort of orange-ish, foamy substance that grew in the reservoir....

Theres no telling how long its been parked w/o brakes...

just curious if anyone else has experienced something similar.. Ill get to finding out why the MC is dry, but the residue left over is baffling me

mike

 

[1BEATK5]

That crap is probably rust because the lid didn't seal, and since there is no brake fluid in the master to soak up the moisture in the air, rust formed.
The other choice would be that it's copper residue. This happens because brake lines are lined with copper to prevent rust, and it slowly comes off the lines and contaminates the fluid and then collects in the bottom of the master cylinder.
that's reason #2 why you should flush wou're brakes every 2 years.
reason #1 is brake fluid is hygroscopic, which means it collects moisture

 

[mike reeh]

hmm it wasnt really rusty looking, but it may have been some wierd type of rust.. it was more powdery, kinda like the stuff that flakes up on your battery cables, but there was a lot of it.. the copper lining seems more reasonable. I did not know the lines were copper lined... thats interesting

mike