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CVO Technical => Drive Train => Topic started by: Mountainman streetbob on November 21, 2019, 08:25:21 PM
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Ok 2012 cvo7 electraglide ultra
Stop and go traffic for an hour
2nd time it's done this
Clutch lever gets closer and closer to handlebar
Then nothing!!! Lever to the bar no pressure at all!
Btw ambient temp 63 deg
Clutch fluid level is good
1. What fluid has the highest boiling point?
2. Do I really need additional oil coolers and a cooling fan for stock oil cooler just for stop and go traffic?
3. Should I move fullsac pipe to top of list priority and get rid of cat converter stock pipe?
4. Bike has power commander v with a tune... runs like a raped ape and getting 42 mpg since finding 02 sensors disconnected... and reconnecting
5 Is there anything in clutch, actuator etc I need to check?
6 when I changed all 4 holes everything looked smelled great
First harley with a hydraulic clutch works great when it works but completely losing pressure really sucks
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The fluid is boiling from the heat of the engine and exhaust. Owner's manual states that it should be changed every two years. I'd put that as a priority service on your list.
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Flush the clutch hydraulic system and refill with fresh DOT 4 fluid, then consider insulating the clutch hydraulic line where it runs in close proximity to the exhaust system. Getting rid of the catalyst should make a significant difference in the amount of heat transferred to the clutch fluid.
Jerry
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6 when I changed all 4 holes everything looked smelled great
i may be missing something, but what is the 4th hole?
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Wow turned 3 holes into 4!
I am a magician!!!
:carrot: :jalapeno: :cucumber:
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Pick yourself up some 1" heat rap and rap the part of the hydraulic line where it's connected to the fram and runs down under the engine belly and near the exhaust that will cure the fluid from boiling.
Had the same problem with mine once I rapped the line with the heat rap haven't had a problem since.
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Some corrugated split wire loom works pretty good for this application, just throwing out some options.
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DEI makes some excellent heat insulating products. They have some that would work great on clutch line. Comes in shiny colors as well as black and different lengths.
Call them and they will tell you which product for your application.
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Like previous, change the fluid.
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Excuse me for being dumb but I don't understand the mechanics of what's going on here. The brake fluid is apparently boiling from exhaust heat releasing oxygen (air) from the fluid & creating 'bubbles' in the line? Where's the fluid going that's displaced by the bubbles, into the master cylinder? I do understand that air bubbles then compress when lever pressure is applied & cause the system to fail but how is the system restored when the fluid cools down? Is the oxygen (air) reabsorbed into the fluid?
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Excuse me for being dumb but I don't understand the mechanics of what's going on here. The brake fluid is apparently boiling from exhaust heat releasing oxygen (air) from the fluid & creating 'bubbles' in the line? Where's the fluid going that's displaced by the bubbles, into the master cylinder? I do understand that air bubbles then compress when lever pressure is applied & cause the system to fail but how is the system restored when the fluid cools down? Is the oxygen (air) reabsorbed into the fluid?
The answer to your questions is "Sorta." :)
Anything in the hydraulic system that is already a gas (like air) or that can turn to gas (i.e., a fluid that boils) can cause loss of braking, ranging from a spongy pedal/lever to flooring the brake pedal/lever (total failure).
The most common things in a hydraulic system that can turn to gas are air, water, and hydraulic fluid (HF)...yes, even HF can boil, although its boiling point temperature is much higher than water. The first HF was water, but soon it was changed to oil to deal with the boiling problem.
As you noted, the bubbles compress when you squeeze the lever, but the slave cylinder doesn't move the brakes (or clutch) until all of the gas has been squeezed back into liquid. If the master cylinder reaches full stroke before all the gas is turned to liquid...hello, foot to the floorboard.
BTW, when the HF exceeds the breakdown temperature, the oil molecules split into smaller molecules. The problem then: the smaller molecules boil at a lower temp than the original full-size molecules, and the fluid loses viscosity (thickness). Then the fluid can leak past the pistons in the cylinders, with the same loss of function as above. This is why I use synthetic HF; just like synthetic engine oil and tranny fluid, it stands up to high temperatures better than dinosaur juice. It does degrade over time, though, so it needs to be changed out. Since your HF already has been boiled, it's definitely time to replace it.
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But neither DOT 3, 4, or 5 are synthetic, are they? Who makes synthetic & what's its trade name?
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But neither DOT 3, 4, or 5 are synthetic, are they? Who makes synthetic & what's its trade name?
Many companies make syn HF, such as Lucas, Shell, Castrol, AMSoil, Mobil, etc. You can get it at any auto parts store like O'Reilly's, AutoZone, Pep Boys. Just look for the word "Synthetic" on the label.
Use DOT 4 for the bike.
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All of my oldie-goldie stuff - '80 Sturgis, '94 RK, '00 RG - came with DOT 5. Any reason I should change to DOT 4? Is there such a thing as synthetic DOT 5?
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DOT 5 brake fluid is silicone based. DOT 3 (standard) and DOT 4 (heavy-duty) are glycol-based. It can be distinguished from conventional brake fluids by its purple color (which comes from a dye).
Silicone does not absorb moisture. DOT 5 brake fluid does not become contaminated with moisture over time as conventional DOT 3 and 4 brake fluids do. Silicone is also chemically inert, nontoxic and won't damage paint like conventional brake fluid. It also has a higher boiling point.
Because of this, it is often marketed as a premium "lifetime" brake fluid. It is often used to preserve brake systems in antique vehicles and those that sit for long periods of time between use.
DOT 5 silicone brake fluid is also very expensive (costing four to five times as much as ordinary brake fluid), and it won't mix with glyco- based brake fluid (creating concern over sludging if all old fluid isn't removed when a system is refilled with silicone).
Silicone also has slightly different physical properties and compressibility, making it unsuitable for ABS systems calibrated to work with DOT 3 or 4 brake fluid.