Clutch Sludge

[Wayn-O]

Hey All,

Just a friendly reminder to check fluids regularly.  I had an experience last night that I wanted to share. 
I have been tinkering around on my Valk that I bought in November since it's too cold to be riding here (wanting to get it all prepped for riding season).  I've been checking things since it's anyone's guess how it was maintained before I bought it.  Last night I decided to bleed the clutch line since I noticed that it was low and discolored.



Yeah, nasty brown/orange.  But what was hiding in the reservoir was even more nasty.



Actual sludge.  It was a semi-soft mass of gunk along with other dark flecks of nastiness.  I was blown away.  Looking back I'm actually surprised that the clutch was actually functional when I was test riding it.  I'm betting that it has never been bled not once.
Now it's nice and clear and full. 

Any ideas as to what may have caused the discoloration and drop in fluid level other than gross neglect?

[The emperor has no clothes]

I just did mine a couple days ago also.  They weren't near as bad as yours but I was surprised at the gunk after just 2 years. The front brake wasn't near as bad as the clutch.

[98valk]

brake fluid absorbs water from the air, some are worst than others. right through the hoses and even the plastic container (ATE comes in metal cans) while its on the self waiting to be sold.
BF turns that color from high moisture content. u should pull the clutch slave cylinder and clean that out also.
always get a brake fluid DOT 4 with a high wet boiling point. ATE and Amsoil Dot 4 are high and don't readily absorb water.

http://www.v8sho.com/SHO/BrakeFluid.htm
http://www.timskelton.com/lightning/race_prep/brakes/brake_fluid.htm
https://www.lelandwest.com/brake-fluid-comparison-chart.cfm

[sandy]

When brake fluid is that bad, I suck out all the fluid. Clean the reservoir and fill with alcohol. Pull that through the system once or twice if necessary until clean alcohol comes out. Pull air through to dry the system. Fill with DOT4 and bleed as usual. A MityVac is what I used till I got a commercial bleeder.

[hubcapsc]

The name of this picture is "gelatonousGlob"... I would have never
known it was in there if I wasn't taking the caliper apart anyhow...
this stuff was like jello, you probably could have made things
with it...



-Mike

[Gideon]

I know there are those that may think it is over kill, but I bleed mine when I change my oil.

Code Select Expand

Once a year or every 5000 miles.

[98valk]

I know there are those that may think it is over kill, but I bleed mine when I change my oil.

Code Select Expand

Once a year or every 5000 miles.

IMHO, yes, overkill for that low miles and normal everyday travel. racing and/or hooligan riding for those miles your change interval is warranted.
most off the self fresh date code, name brand BFs are good for 2-3 yrs with rubber hoses, 3-4 with SS Teflon lined hoses. ATE which is a very low hygroscopic BF is good for even longer. ATE sells same product but different colors, so when changing one will know when all of the old is gone from the system.
and changing that often puts a very harsh chemical into the waste stream more often and some recycle places are not taking BF or charging for it.

[WintrSol]

Brake fluid used in brakes is good for 2-3 years; I usually change mine at 2. Used in clutches is different, because of the higher temperatures in use, and wider temperature swings; because of this, it gets brown in a year, so I change it.

[98valk]

Used in clutches is different, because of the higher temperatures in use, and wider temperature swings; because of this, it gets brown in a year, so I change it.

I have to disagree with this. for the GL1500 engine the slave cylinder is attached to the outside of the engine.  brake calipers will easily see 220-300+ F temps much more than the slave cylinder.
for the most part street seen temperatures don't degrade the BF, moisture is what does it.

[WintrSol]

Brake calipers can get that hot, yes, but they don't stay that hot (unless you're dragging them down a mountain - don't do that). The back of the engine is nearly oil temperature, and stays there for nearly the entire ride, so the average temperature in the clutch slave is much higher than that of the calipers. Clutch fluid gets brown a lot faster than brake fluid, and the higher average temperature is the reason.