keep an eye on your brake and clutch fluid

[FJReady]

Today I put a new set of rear brake pads in and decided while I was at it I'd flush the brake lines, F&R. The fluid came out a little darker than I remember it being upon installation two years ago, but nothing alarming. Then I opened the clutch reservoir and holy crap- it was gray and sploogy. Instead of flushing it through the lines and slave cylinder, I sopped it out with a few paper towels. Then flushed through about 3 reservoirs full of fresh synthetic DOT 4. The stuff that came out of the slave cylinder bleed valve was clear so I don't think any of the contaminated stuff made it through the line to the clutc cylinder but it sure reminded me that the two year recommended fluid change has merit. It seems I have a path in the clutch master cylinder or reservoir that allows moisture in. The top side of the rubber diaphram did seem to have some condensation of it so I guess its not doing its job entirely since something obviously got past it.

So watch your maintenance schedules.

 

[jpcfjr]

Today I put a new set of rear brake pads in and decided while I was at it I'd flush the brake lines, F&R. The fluid came out a little darker than I remember it being upon installation two years ago, but nothing alarming. Then I opened the clutch reservoir and holy crap- it was gray and sploogy. Instead of flushing it through the lines and slave cylinder, I sopped it out with a few paper towels. Then flushed through about 3 reservoirs full of fresh synthetic DOT 4. The stuff that came out of the slave cylinder bleed valve was clear so I don't think any of the contaminated stuff made it through the line to the clutc cylinder but it sure reminded me that the two year recommended fluid change has merit. It seems I have a path in the clutch master cylinder or reservoir that allows moisture in. The top side of the rubber diaphram did seem to have some condensation of it so I guess its not doing its job entirely since something obviously got past it.
So watch your maintenance schedules.

Just flushed all the fluids (brake and clutch) yesterday. I noticed the same thing about the clutch fluid...it was nasty. This is on a '09 with 10,400 miles. Shop mechanic recommended I take a look at the fluid and see if it needed changing even though they usually recommend a 2 year interval. I just figured the sight glass was foggy...NOT.

I wish I had thought of sopping up the yuck instead of flushing it all out but oh well, done now.

 

[Fred W]

Yeah, there is something in the clutch circuit that makes it look much worse than either brake line. But the good news is the clutch fluid doesn't get hot like the brakes do, so no worries about boiling the fluid. As long as it doesn't get too much water absorbed into it, which changing it bi-annually should ensure, you shouldn't have any corrosion issues,

I use a MityVac hand pump to bleed/flush them all, which makes the job super easy.

Before getting started just stick the end of the MityVac's hose in the open reservoir and suck it (nearly) dry. Just try not to go so low that you get air in the fluid intake. You could also just abscond the wife's turkey baster, but that tends to be messier (you don't want to drip brake fluid on anything) and also make your next turkey taste kind'a funny. :blink:

 

[HaulinAshe]

My theory is the additional clutch fluid splooge is caused by the stored lean angle of the bike on the side stand. The reservoir cap vent openings above the fluid separator membrane, tend to favor moisture and grime collecting on the clutch side.

Only way to prove or disprove the theory is for somebody to F&R two bikes and let one sit on the center stand, the other on its side stand, both for about six months and then compare them.

I'll stick to changing all my fluids every year.

 

[Yambone]

Only way to prove or disprove the theory is for somebody to F&R two bikes and let one sit on the center stand, the other on its side stand, both for about six months and then compare them.

Or just ask the Brits and the Aussies. They must have kickstands on the right, eh? If not how could they park on the left side of the road, they'd surely tip over.

Can anyone give a summary of how a clutch might act with old fluid? I just rode a freinds '05 that he acquired with 40K miles. The clutch seemed kind of twitchy, not as smooth as my '04. Will old fluid do that? He hasn't done anything for maintenance yet and didn't get previous maintenance history.

 

[jpcfjr]

Yeah, there is something in the clutch circuit that makes it look much worse than either brake line. But the good news is the clutch fluid doesn't get hot like the brakes do, so no worries about boiling the fluid. As long as it doesn't get too much water absorbed into it, which changing it bi-annually should ensure, you shouldn't have any corrosion issues,
I use a MityVac hand pump to bleed/flush them all, which makes the job super easy.

Before getting started just stick the end of the MityVac's hose in the open reservoir and suck it (nearly) dry. Just try not to go so low that you get air in the fluid intake. You could also just abscond the wife's turkey baster, but that tends to be messier (you don't want to drip brake fluid on anything) and also make your next turkey taste kind'a funny. :blink:

Heh, I used my mityvac as well. Negates asking one of the kids or wife to help and avoids the "loosen, down, tighten, up, loosen, down, tighten, up, loosen..." And no, that is not a new sex move. (It's actually an OLD sex move)

 

[HaulinAshe]

I'm not about to ask what else you pervs do with your MightyVac Hand Pumps!

 

[FJReady]

Negates asking one of the kids or wife to help and avoids the "loosen, down, tighten, up, loosen, down, tighten, up, loosen..."

That how I do it, solo however. If I asked for help even from the well meaning wife or kids, I'd surely end up with brake fluid all over the bike and/or air in my brake lines. I have many examples that prove my communication skills with the loved ones are not advanced enough to coordinate the dexterity required to pull off the moves described.

 

[ShowMeMo]

I'm not about to ask what else you pervs do with your MightyVac Hand Pumps!

The electric version would be much less work...



Funny, I was going to stop and get some Dot4 today since I noticed the sight glass lookin empty on the clutch side.. no leaks on my 09 so figured it was just low...

 

[ScottyUSN]

New trick to me, maybe old school for others.

I just replaced the clutch master and slave cylinders on "MY" son's Acura. I suspect it should work just fine on the bike. Fluids on the bike are a year old, so after what I've read here, I will try this method on the bike soon.

Service the fluid from bottom up using the bleed valve using an small oil can and section of tubing.

$5.00 oil can purchased at any Wal Mart, Autozone, along with some tubing that will fit the bleed valve and the oil can fitting (typically close to the same size). I got both at OReilly's.

Take all cautions to keep brake fluids off any surfaces especially paint. Moving handlebars and an open brake or clutch reservoir is an accident wating to happen.

Purge your existing fluids. I go turkey baster all the way to the bottom first. Trying to get out as much settled spooge as possible. Reminder: (I promise the wife I would replace turkey baster before October).

With your oilcan loaded with your favorite DOT, and your tubing in place on the bleed valve. Open the bleed valve, and ensure your cap is cracked or off fluid resevoir. Now pump the fluid from the oil can into the bleed valve.

You should soon see your reservoir filling, and your air bubbles gravity forced (air want to rise) out the top. Once your fluid reservoir is filled, tighten the bleed valve and your done. Or repeat if you feel it's needed.

 

[jpcfjr]

Scotty, that is an unusual method but hey, whatever works.

 

[jpcfjr]

Only way to prove or disprove the theory is for somebody to F&R two bikes and let one sit on the center stand, the other on its side stand, both for about six months and then compare them.

Or just ask the Brits and the Aussies. They must have kickstands on the right, eh? If not how could they park on the left side of the road, they'd surely tip over.

Can anyone give a summary of how a clutch might act with old fluid? I just rode a freinds '05 that he acquired with 40K miles. The clutch seemed kind of twitchy, not as smooth as my '04. Will old fluid do that? He hasn't done anything for maintenance yet and didn't get previous maintenance history.

I don't think you would notice anything at all until you had cylinder failure. The clutch will either operate or not. The cleanliness of the fluid probably won't make any difference until you have so much compressible gook in there that the clutch fails to operate at all. It would probably take years of neglect for that to happen quite frankly.

But who knows, your friends bike may be at that point. I recommend changing the fluid for 5 bucks and see what happens.

 

[Fred W]

New trick to me, maybe old school for others.
I just replaced the clutch master and slave cylinders on "MY" son's Acura. I suspect it should work just fine on the bike. Fluids on the bike are a year old, so after what I've read here, I will try this method on the bike soon.

Service the fluid from bottom up using the bleed valve using an small oil can and section of tubing.

$5.00 oil can purchased at any Wal Mart, Autozone, along with some tubing that will fit the bleed valve and the oil can fitting (typically close to the same size). I got both at OReilly's.

Take all cautions to keep brake fluids off any surfaces especially paint. Moving handlebars and an open brake or clutch reservoir is an accident wating to happen.

Purge your existing fluids. I go turkey baster all the way to the bottom first. Trying to get out as much settled spooge as possible. Reminder: (I promise the wife I would replace turkey baster before October).

With your oilcan loaded with your favorite DOT, and your tubing in place on the bleed valve. Open the bleed valve, and ensure your cap is cracked or off fluid resevoir. Now pump the fluid from the oil can into the bleed valve.

You should soon see your reservoir filling, and your air bubbles gravity forced (air want to rise) out the top. Once your fluid reservoir is filled, tighten the bleed valve and your done. Or repeat if you feel it's needed.

That is a very good method in certain tricky bleeding situations, specifically where it is hard to get the air out of the lines because the air bubbles keep gravitating upward as you bleed.

But for an annual or bi-annual fluid exchange only, with no air bubbles to contend with, be aware that you will introduce a good sized air bubble into the fluid (from the air in the nipple when you first connect the oil can pump), so you'll need to be sure to continue bleeding long enough to clear that bubble. You also need to pump for a while, then suck out the fluid from the reservoir, and repeat. You don't want the old cruddy fluid from the lines being left in the reservoir. Not really a big problem, it just may take a while longer then the standard "suck from the bottom" technique.

 

[Constant Mesh]

The clutch fluid likely gets dirtier quicker due to its more aggressive workout. The seals in the master and slave cylinder experience a lot more piston movement. When you operate the clutch you may stroke the pistons their maximum travel. So, the seals may wear away more rapidly dumping their dregs into the fluid.

Every time you operate the clutch there is a back-and-forth fluid flow of almost 2 CC's. That's a lot of fluid mixing and churning that the brakes don't experience.

 

[Dr. Bones]

Can anyone give a summary of how a clutch might act with old fluid? I just rode a freinds '05 that he acquired with 40K miles. The clutch seemed kind of twitchy, not as smooth as my '04. Will old fluid do that? He hasn't done anything for maintenance yet and didn't get previous maintenance history.

It's not scientific proof but when I bought my '04 last fall @30,000 miles and changed the fluids this spring, I immediately noticed the clutch was buttery smooth after the change. I doubt the previous owner had done any maintenance. So yes, I think it makes a difference. The change is so easy and quick once you have the equipment, just change it!

 

[FJReady]

It's not scientific proof but when I bought my '04 last fall @30,000 miles and changed the fluids this spring, I immediately noticed the clutch was buttery smooth after the change. I doubt the previous owner had done any maintenance. So yes, I think it makes a difference. The change is so easy and quick once you have the equipment, just change it!

Thats how mine felt today after the fluid change, buttery smooth. Getting that old smegma outta there improved clutch feel. Its one of those thing that deteriorates very slowly I guess. Easy to notice when it's restored, not so easy on the way there.

 

[jpcfjr]

It's not scientific proof but when I bought my '04 last fall @30,000 miles and changed the fluids this spring, I immediately noticed the clutch was buttery smooth after the change. I doubt the previous owner had done any maintenance. So yes, I think it makes a difference. The change is so easy and quick once you have the equipment, just change it!

Thats how mine felt today after the fluid change, buttery smooth. Getting that old smegma outta there improved clutch feel. Its one of those thing that deteriorates very slowly I guess. Easy to notice when it's restored, not so easy on the way there.

I felt absolutely ZERO difference in the performance of the clutch after changing the fluid and I have about 100 miles already. It just felt good inside (ME) to do it. I can't help it...I love my mechanical things!

I also surmised the same thing as to why the clutch fluid looked so much worse than the brake fluid. Clutch gets SUBSTANTIALLY more use than the brakes and indeed moves more fluid probably causing quicker breakdown of rubber seals.

 

[Gary F]

Yeah, there is something in the clutch circuit that makes it look much worse than either brake line. But the good news is the clutch fluid doesn't get hot like the brakes do, so no worries about boiling the fluid. As long as it doesn't get too much water absorbed into it, which changing it bi-annually should ensure, you shouldn't have any corrosion issues,
I use a MityVac hand pump to bleed/flush them all, which makes the job super easy.

Before getting started just stick the end of the MityVac's hose in the open reservoir and suck it (nearly) dry. Just try not to go so low that you get air in the fluid intake. You could also just abscond the wife's turkey baster, but that tends to be messier (you don't want to drip brake fluid on anything) and also make your next turkey taste kind'a funny. :blink:

What model of MityVac do you use? When I do a search a multitude of models comes up.

 

[Fred W]

I actually have an older version of what is now the MV8000. The pump has a plastic body, but is cheaper than the all metal units.