Topic: Someone's filled up my master brake cyl with orange marmalade?!

[bleuquila]

   Well, okay not really.  But it sure looks like it.  Is this a normal thing for blake fluid to do after a few years?

I cleaned out the most of it, and sprayed some brake cleaner in to get the residue off, and filled it up with new fluid to soak for a while.. .what I'm not sure about is if the entire length of brake like is going to be filled with this gunk as well, and if it's a hopeless cause?  (the line, that is)

I need to swap calipers from the parts bike to find out, I suppose, the bleeder valve on this bike is rusted solid, so there's not much I can do with it right now.

Sorry for the crap quality photo, forgot my real camera 

[Salem350F]

The stuff in the caliper will probably look worse.  The gunk all settles to the bottom even if you flush the system.  I would suggest a complete teardown and cleaning, even if you get a new "used" caliper.

[Steve F]

 ;)Not to worry, mine looked like that too.  It took a complete tear-down and cleaning to get it back to operational, and a rebuild kit for the master cyl.  You should consider new hoses anyway, as those dry rot over time.  The caliper seal should be removed and the groove that it sits in should be cleaned with a plastic tool of some kind so you don't damage the groove walls.  Check the piston in the caliper for pitting or chrome coming off.  Small pits about the size of this (.) are not a problem, as the seal will "bridge" these and not leak.  If the bleeder is stuck, a little heat from a propane torch and using a 6-point socket will generally loosen it (don't use a 12-point socket). If the piston is stuck, remove the caliper from the bike, remove the hose and hand tighten a bolt in the caliper where the hose came out of.  Once the bleeder is loose, attach a grease gun to the bleeder to pump out the piston.  Clean it out and inspect the parts. Someone on this board was making caliper pistons if you need new ones.

[Dennis]

I've seen more than a few that looked exactly like that. Disassembled, cleaned, lube with fresh brake fluid, put them back together and they worked.
I have sometimes found brake likes completely blocked with the stuff also.

[bleuquila]

okay, guess I should probably just get a new line. 

I can see how future conversations are gonna go:

Me: So, uh... I was taking apart my bike some more and X part looks kinda worn.. it's been 5 years, shoudl I ... ?
Everyone Else:  Replace it.
Me: Right, so uh.. I'll just replace that, then!

Funny thing is, the system on the "parts bike" is full of blake fluid still - kinda dirty looking, but liquid!  So, hopefully using the caliper from that one will be less trouble.

[Bob Wessner]

I followed the exact instructions SteveF posted on a brake system after 22 years, including the new brake lines. Works fine now.

[pmpski_1]

Just out of curiosity, what causes brake fluid to do this?

Obviously it's changing to a solid, but has it gotten water mixed in and then the water is evaporating? Or does temperature cause this?

[Jonesy]

Water absorbtion accounts for the orange color (brake fluid get darker as it pick up water)... not sure about the solidification. I read somewhere the solids are mineral salts that accumulate in the system.

[bryanj]

This is why all the manufacturers say change the fluid every two years!!

[bleuquila]

Who knew there was actual science behind those manufacturer's instructions!

Of course, this doesn't explain why of two bikes in storange for the same length of time, one ended up with jelly in the lines and one is still liquid. 

[TwoTired]

What two bikes?
Was the brake fluid the same age?
Do they use the same type of fluid?
Were they stored in indentical conditions?
Is the cap diaphram/seal still intact on both?

[MikeDeB]

Use denatured alcohol to clean the internals of the master cylinder and caliper.  I then follow that by a cleaning in the ultra sound.  Works every time.   

[bleuquila]

What two bikes?
Was the brake fluid the same age?
Do they use the same type of fluid?
Were they stored in indentical conditions?
Is the cap diaphram/seal still intact on both?

a 72 (runing bike) and 71 (parts bike) CB500s
Not sure about fluid, but since the 71 wasn't being ridden prior to the long lock-up if anything, that fluid is older.  Yet the 71 was the one with liquid in it, not jelly
yes
yes


MikeD: Is denatured alcohol the same as the common Brakleen or other variants of brake cleaner?   And what's that ultrasound business?  Pretty sure my bikes not pregnant 

[Jonesy]

MikeD: Is denatured alcohol the same as the common Brakleen or other variants of brake cleaner? And what's that ultrasound business? Pretty sure my bikes not pregnant

I can answer these for ya. Denatured alcohol is not the same as Brakleen. Brakleen is a volatile (sometimes chlorinated) solvent so it will clean off most oils and evaporate very quickly. I don't know exactly what make alcohol denatured (I believe there is some kind of distillation done to it), but you can find it at the hardware store in where they have the stuff for wood finishing.

An ultrasonic cleaner is a tank that the part to be cleaned is suspended in. The tank is filled with water and a cleaning agent suitable for the material being cleaned. The part is blasted with ultrasonic pulses, loosening up any grime, corrosion, etc. It works great for carbs, too. These tanks are what jewelers use to clean jewelry. There is one at work I use, but small (half gallon) ones are available in catalogs and online.