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[SPEEDDY]

While driving in stop and go traffic on a hot Florida day my clutch lever went soft. No pressure unless you pumped the lever. After the bike cooled down the hydraulic pressure came back and was fine the rest of the day. Has anyone ever herd of boiling hydraulic clutches. Has this happened to anyone else?

[Shovelhead]

The hydraulic clutch on my 2008 has actually done that several times when cold. In fact, I've gotten into the habit of giving it a few pumps before dropping into first on initial takeoff when it's cold.

[SIX38]

Hydraulic fluid absorbs moisture over time. If the moisture content gets high enough and the fluid get above 212 degrees, the liquid (water)can "flash" to a vapor, which will give the same effect of air in the system. As it cools, it will return to a liquid state and the system will work properly. A flush and change of the fluid is the fix. Always use new fluid from a sealed can.
Tom P.

[SPEEDDY]

This would make sense, as with overheating brakes. The hot exhaust from sitting in Orlando FL traffic boiled my fluid. I will begin with a flush, I just wandered if anyone else had this happin.

[mjb765]

Had the same thing happen to me after replacing the clutch line a few months ago. Got home and had to bleed it and it's been good ever since. Thought it was boiling as well because it happened a few times that day when it was really hot. Then when things cooled down a bit the problem was gone for a little while. Not sure if it was boiling since bleeding fixed my problem.

[AXIL]

   flush the fluid at lest once a year. and by the way i used to live in brandon is life still good there?  axil

[PierceEye]

While driving in stop and go traffic on a hot Florida day my clutch lever went soft. No pressure unless you pumped the lever. After the bike cooled down the hydraulic pressure came back and was fine the rest of the day. Has anyone ever herd of boiling hydraulic clutches. Has this happened to anyone else?

Hey Speedy.......Tampa here...where in Tampa and what are you riding?

Roger

[rxbob]

I just got back from having 2010 SEUC towed to the dealer.  I have the close to the same symptom.  Mine goes completely limp.  If you pump it, some resistance is felt, but not enough to disengage the clutch.  It takes at least a half hour before returning to normal.  This is the second time. Last year it wasn't all that hot, but i was in stop and go traffic for about an hour.  The dealer (away from home) got it and we did find a small leak on the banjo fitting.  We thought that was it.  I have been a little paranoid about it and have been checking the fitting for leaks anytime I have to use the clutch a grunch.  It happened again today.  After changing my underware, we got it to the dealer.  No leaks this time.  last year we rode on the 2 days it was 105 here, but no stop and go and no problem.  Seems to be all the extra heat that builds up in stop and go traffic.  Will let you know what the dealer tells me.

Cheers, 
Bob

[CVOThunder]

Wonder what it would take to go to Synthetic or is it already being used? DOT 5 could be an option but not sure what the specs are and you might need to clean all the lines along with master and slave. Might be worth checking into and I don't have any manuals here.

[grc]

Wonder what it would take to go to Synthetic or is it already being used? DOT 5 could be an option but not sure what the specs are and you might need to clean all the lines along with master and slave. Might be worth checking into and I don't have any manuals here.

DOT 5.0 is silicone based and not compatible with ABS systems, so there isn't much call for it anymore.  There is a new DOT 5.1 synthetic that is not silicone based and is compatible with the other glycol fluids like DOT 3 or DOT 4.  It has higher dry and wet boiling points, which might be worthwhile in this clutch application. 

These are the minimum boiling points for each spec (wet boiling point is defined as 3.7% water by volume):

                  Dry boiling point          Wet boiling point
DOT 3          205 °C (401 °F)          140 °C (284 °F)
DOT 4          230 °C (446 °F)          155 °C (311 °F)
DOT 5          260 °C (500 °F)          180 °C (356 °F)
DOT 5.1        270 °C (518 °F)         190 °C (374 °F)  

Those are the minimum boiling points, but there are differences between brands that can jack those numbers up significantly.  Check the data sheets for the various brands when buying fluid.

BTW, even with brand new fluid with zero moisture, note that the fluids still boil at temperatures that are much lower than the exhaust pipe temps at the collector.  If this becomes a persistent problem, shielding of the clutch line near the exhaust may solve it.  Just curious, but how many of the folks experiencing this clutch problem still have the catalytic converter in the collector pipe?  I don't remember this being a problem on the earlier models that didn't have the current exhaust design and cat.


Jerry

[CVOThunder]

Great info Jerry and thanks for posting it like that. YOu could be onto something about the heat from the cat being an issue. My 78 Superglide would boil the master cylinder after I got rid of the stock truck pipe and put on shot guns. Welded forward control tabs on the frame and moved it all forward, problem solved. I didn't even think about the stock exhaust location on our rides being an issue until you pointed it out. Shouldn't be a problem while I'm running true duals but if I decide to go with the Fullsac X pipe then I'm putting the heat back in the same area. Having the Fullsac with ceramic coatings might keep the heat somewhat isolated. Good questions to think about.

[SIX38]

I believe Jerry [grc] has hit the nail on the head (as usual  ). Before I made any modification to my '09 SEUC, I took some temperature readings for before and after comparisons; (surface readings taken with a Fluke thermocouple meter)

Stock 2009 SEUC
Air Temperature                 80 deg
Front Pipe @ O2 sensor       728 deg
Rear Pipe @ O2 sensor        960 deg
Collector Pipe @ cat          1041 deg
Oil temp                           273  deg (yikes)

The clutch hydraulic line with its metal end fitting is sitting right there next to the exhaust components and the transmission side cover with its integral clutch actuator piston is sitting just above the cat. As Jerry pointed out, dry DOT 4 fluid boils at 446 deg F. so boiling the fluid sure is a possibility especially if the cat is still present. And the solution is???
I wonder how often this is happening, but this is certainally in the category of a real safety issue.

Tom P. 

[rxbob]

Brought bike home with no resolution. The dealer could not replicate the problem.  I do have a ticket number with the manufacturer, so I called and asked if there was anything I should do or look at if it happens again.  There was nothing they could think of.  I asked if the problem could be replicated, what would they do then (they would have the exact information they have now).  At least I think he understood my point.  Still does not solve the problem.  They say this is the first hydraulic clutch that has done this!!! Guess I will keep a video camera with me to show them what I have described.  They even thought it could be from an after market exhaust, but I am stock, and aftermarket would most likely remove the problem.  NO JOY