Dirty Clutch Fluid

[2 Cruysyn]

2011 RTS SM5 6k miles.

Checked the fluid level in the clutch reservoir today to find that the level is probably where it was originally, or at least near to it, but the fluid is pretty dirty. Also found some gunk stuck to the "expanding" part of the reservoir seal. I have had NO problems with the clutch. It was just time to check the fluid level.

Found a couple mentions of dirty fluid in other threads but nothing specific as to how something somewhat clear to begin with gets dirty in a closed system.

Also found in another thread a comment that suggests BRP acknowledged a problem with o-rings (black) used early on and has changed to an o-ring (green) of a different composition (my assumption) that holds up better in the presence of DOT4 fluid.

Is dark clutch fluid (or break fluid for that matter) a problem with or without the gunk I removed from the reservoir seal?

Did BRP change to an 0-ring of a composition more suited for DOT4 fluid and if so when did that change take place?

In light of all this is it something I need to address yesterday?

 

[SpyderLady]

I have a 2011 Rt manual. Cowtown has drained and flushed the clutch reserve and line two times because it was so dirty. Now I have been having problems with my clutch in that it was extremely hard to shift especially from reverse to first and I could hardly ever get it in neutral. Cowtown tore into my clutch area to find a rod that had a crack in it and a few other issues. Don't know if this was the reason for dirty fluid but my bike is running much better. I would definitely have it checked. At first BRP did not want to cover under warranty even tho I had only had my RT since January and we had proof of problems starting before June, they tried to declare it was normal wear and tear. NOT!! Get it checked is mt advice

 

[NancysToy]

Same problem here. I have taken to flushing the fluid at every oil change. No answers from my dealer as to a solution as yet.

 

[NancysToy]

Obviously the "dirt" is clutch dust that must be somehow wicked back into the system through an improper slave cylinder seal?
Or something else?

Not likely. Wet clutches don't make dust, in the traditional sense, and any material sluffed off goes into the oil, where it is removed by the oil filter. The color is more likely due to the O-rings deteriorating. Because there is no recirculation in the hydraulic system if it is tight, so it is most likely due to deterioration in the master cylinder when it shows at the top of the system, and in the slave cylinder when it shows dark when first bled. Unfortunately, with sufficient o-ring deterioration or bore wear at either end, fluid will begin to circulate, and make determination of the source more difficult. A complete rebuild or replacement of the system is probably in order. I will do mine when I replace the clutch kit this winter. My dealer may spring for a new master cylinder under warranty. I have complained about the problem since the 600 mile service interval.

 

[Farmboy]

I have my clutch torn apart as we speak. because of it leaking. The o-rings in the slave was about dissolved and looked like black mud inside.

My answer is at the factory they used a grease to install the piston to avoid tearing the o-rings. That grease melted the o-rings over time. That grease also migrated up into the reservoir. Mine had enough grease to repack a wheel bearing! :banghead:

 

[Farmboy]

Sounds as if you may have cracked it.
Congrats! :clap:

Now, on the rebuild how are you going to do it?

Just waiting on ups to bring me my o-rings that I ordered from BRP. going to use marine grease...very sparingly.

 

[Bob Denman]

This is really curious...
Why would they use a grease to prevent o-ring damage that actually eats the o-rings?? :shocked:
Why wouldn't one of their engineers think to check that out?
:gaah:
Even I've heard of "galvanic corrosion"... A couple of things not liking each other can upset the applecart! :yikes:
Are the o-rings a size that could be found in perhaps a higher quality replacement part from somewhere else?
(Thinking of the Honda gaskets that work so well in the RS/GS exhaust systems...)

 

[NancysToy]

I don't like to use any grease on seals that contact brake fluid. Too easy to contaminate the fluid. It can also be incompatible with the O-rings, as Farmboy has shown. In my experience, though, if the grease attacks the O-rings, so will the brake fluid. Apparently BRP didn't think out their materials very well. I just use a little brake fluid as a lubricant for assembly.

BTW, Farmboy, let us know if the rebuild helps the clutch work better. It isn't uncommon for slight leakage at the slave cylinder or master cylinder to reduce clutch travel.

 

[gypsy_100]

I don't like to use any grease on seals that contact brake fluid. Too easy to contaminate the fluid. I just use a little brake fluid as a lubricant for assembly.

BTW, Farmboy, let us know if the rebuild helps the clutch work better. It isn't uncommon for slight leakage at the slave cylinder or master cylinder to reduce clutch travel.

Conventional wisdom is always to just use brake fluid on all the rubber parts when assembling any brake components. I just checked the BRP shop manual and that's their procedure for rebuilding the master and slave cylinders. So it seems very strange that production assembly would differ from that. But I certainly can't explain Farmboy's findings.

Since my slave rebuild (due to a damaged o-ring), the clutch behavior is not any different. The clutch does not begin to engage until the hand lever is almost fully let out. I guess that's just a characteristic of their design. Leakage or air in the system would move it the opposite direction, causing engagement sooner in the handle travel or even causing the clutch not to disengage completely.

 

[NancysToy]

Conventional wisdom is always to just use brake fluid on all the rubber parts when assembling any brake components. I just checked the BRP shop manual and that's their procedure for rebuilding the master and slave cylinders. So it seems very strange that production assembly would differ from that. But I certainly can't explain Farmboy's findings.

Since my slave rebuild (due to a damaged o-ring), the clutch behavior is not any different. The clutch does not begin to engage until the hand lever is almost fully let out. I guess that's just a characteristic of their design. Leakage or air in the system would move it the opposite direction, causing engagement sooner in the handle travel or even causing the clutch not to disengage completely.

Yep, with mine the clutch does not disengage properly, especailly when worn. That problem may be compounded by possible warped clutch plates. The new clutch kit has revised plates. I doubt that Rotax is using grease for assembly, although stranger things have happened. I suspect what looks like grease is deteriorated rubber, mixed with brake fluid to form a greasy "mush". As you have confirmed, conventional wisdom is to use the fluid being contained as O-ring lube if the fluid is a petroleum product. If that causes problems, the O-ring material wasn't compatible in the first place.

 

[Bob Denman]

Curiouser and curiouser...

What is it; if not grease? :dontknow:

 

[DrewNJ]

There are not very many "rubber" type materials that play nice with brake fluid....
http://www.sealingspecialties.com/materials.htm

Anyone have some dimensions? There are not many I haven't been able to source for projects in the past from McMaster. Seems Aflas or EPDM may be the way to go.
http://www.mcmaster.com

 

[DrewNJ]

This site has some good info too.
http://www.efunda.com/designstandards/oring/oring_chemical.cfm?SM=none&SC=Brake Fluid

I agree, only use brake fluid as the o-ring lube during assembly.

 

[Farmboy]

Yep, with mine the clutch does not disengage properly, especailly when worn. That problem may be compounded by possible warped clutch plates. The new clutch kit has revised plates. I doubt that Rotax is using grease for assembly, although stranger things have happened. I suspect what looks like grease is deteriorated rubber, mixed with brake fluid to form a greasy "mush". As you have confirmed, conventional wisdom is to use the fluid being contained as O-ring lube if the fluid is a petroleum product. If that causes problems, the O-ring material wasn't compatible in the first place.

You may very well be right!! I said it was grease but it could be rubber? There was a lot of black, thick goop all in the system.

 

[Farmboy]

If Farmboy would take the grease he found and spread it like butter onto a piece of plywood and wait a day or two and if the stuff is still like grease it's grease.
If it it stiffens up it's not.

Dang, I done washed it all in the parts washer. never thought of that as a test.

 

[2 Cruysyn]

If Farmboy would take the grease he found and spread it like butter onto a piece of plywood and wait a day or two and if the stuff is still like grease it's grease.
If it it stiffens up it's not.

I placed the gunk I removed from the reservoir seal on a shop towel so that I can make my case when I visit my dealer. The towel has pretty much absorbed what fluid there was. What is left is a black sticky glob that feels like liquid rubber.

 

[NancysToy]

What concerns me is the other end of the system. The same O-ring material, if used in the master cylinder, would deteriorate there, too. Unlike the slave cylinder, the master is not rebuildable...or at least BRP doesn't show parts. I don't really feel like shelling out $255 just to replace those O-rings. Unfortunately, these don't seem to fail completely too often, and can't be dismantled and inspected, so convincing the dealer (and BRP) to replace the master cylinder hasn't been successful. I'm 90% sure that the dirtiness we see at the top is coming from the master cylinder, at least at first blush. The crud at the bottom is the fault of the slave cylinder. Fluid moves in a linear fashion through a hydraulic system of this nature, much like a piston. It is not recirculated to the reservoir, so it is very hard to get debris at the "push" end, unless the connecting line is large and the cylinders at one end or the other leak by badly. In my opinion, the components should be replaced at both ends if the problem is to be resolved.

 

[Farmboy]

What concerns me is the other end of the system. The same O-ring material, if used in the master cylinder, would deteriorate there, too. Unlike the slave cylinder, the master is not rebuildable...or at least BRP doesn't show parts. I don't really feel like shelling out $255 just to replace those O-rings. Unfortunately, these don't seem to fail completely too often, and can't be dismantled and inspected, so convincing the dealer (and BRP) to replace the master cylinder hasn't been successful. I'm 90% sure that the dirtiness we see at the top is coming from the master cylinder, at least at first blush. The crud at the bottom is the fault of the slave cylinder. Fluid moves in a linear fashion through a hydraulic system of this nature, much like a piston. It is not recirculated to the reservoir, so it is very hard to get debris at the "push" end, unless the connecting line is large and the cylinders at one end or the other leak by badly. In my opinion, the components should be replaced at both ends if the problem is to be resolved.

Your making me agree. Now stop it! Your scaring me! Wife says no more moneys for me!:yikes: LOL.

 

[NancysToy]

Update

I was able to shed a little more light on this problem after a conversation with a friend at BRP. Apparently the master cylinder is not a worry. The sludge at the top of the system is being caused by aluminum and rubber particles floating to the top of the system. The problem originates in the slave cylinder. Not only do the O-rings deteriorate, but the slave cylinder itself, what BRP calls the anti-friction bushing, becomes scored and worn. Eventually loss of clutch fluid, possible clutch slipping due to premature wear, or a complete loss of clutch disengagement can result.

The proper repair will consist of replacing both piston O-rings, the piston, the anti-friction bushing (cylinder), and the two bushing O-rings. The repaired system should be thoroughly flushed and bled before being returned to service, in order to clean out any debris accumulated in the remainder of the system.

There is not a service bulletin addressing this problem as yet, but BRP should be making techs aware soon...possibly via notification on WebBoss. If you have an SM5 Spyder, especially one nearing the 20,000 mile range, and you have seen dirty clutch fluid, a rebuild would be in order before complete failure occurs. If you merely replaced the O-rings during a rebuild, you should do the job again, and replace the piston and bushing, too.

 

[Farmboy]

I was able to shed a little more light on this problem after a conversation with a friend at BRP. Apparently the master cylinder is not a worry. The sludge at the top of the system is being caused by aluminum and rubber particles floating to the top of the system. The problem originates in the slave cylinder. Not only do the O-rings deteriorate, but the slave cylinder itself, what BRP calls the anti-friction bushing, becomes scored and worn. Eventually loss of clutch fluid, possible clutch slipping due to premature wear, or a complete loss of clutch disengagement can result.

The proper repair will consist of replacing both piston O-rings, the piston, the anti-friction bushing (cylinder), and the two bushing O-rings. The repaired system should be thoroughly flushed and bled before being returned to service, in order to clean out any debris accumulated in the remainder of the system.

There is not a service bulletin addressing this problem as yet, but BRP should be making techs aware soon...possibly via notification on WebBoss. If you have an SM5 Spyder, especially one nearing the 20,000 mile range, and you have seen dirty clutch fluid, a rebuild would be in order before complete failure occurs. If you merely replaced the O-rings during a rebuild, you should do the job again, and replace the piston and bushing, too.

Wow! 20,000 miles? I only got 6000! I did see ware on the bushing. I polished it. my not last long. good to know