Issues bleeding clutch fluid, clutch no longer works!

Hey guys, I'm new to the forums (I'll post a pic when I get my bike back on the road). First post, I've been trying to solve my issues up till now with searching and reading older threads. So thanks for all the help so far.

I've recently been trying to give my bike a thorough tune up as I've had it for a couple years now and haven't done much besided change the oil. Everything was going fine untill I went to clean the chain. I took off the clutch slave cylinder with the rest of that assembly so that I could get to the front sprocket and take the chain off. Mid way through cleaning the chain, the cylinder/spring piece fell out and I got clutch fluid all over my floor. So now it's time to change the clutch fluid too. Thank goodness I hadn't gotten to that step yet.

I've been watching a few instructional videos on how to bleed the clutch fluid online, since the instructions in the book are really poorly worded. Seems simple enough. My clutch currently has no pressure on it since there's a lot of air in the system. So when I go to try and pump through fresh DOT 4 fluid, it eventually starts coming out the hose, really slowly. But pressure on the clutch never builds. You can push it all the way in with almost no effort, and it has no effect when the bike is on.

I don't see any leaks. From my experience with this job so far, I think I have a basic understanding of how the clutch system works. I feel like in my system currently there isn't enough fluid to create enough pressure to push on the slave cylinder hard enough for it to push in the rod that goes into the crank case. Not sure if the fluid is leaking somewhere? I don't see it coming out anywhere besides the drain hose. When I had the slave cylinder open everything seemed tight and clean.

I hope this isn't a huge issue, like fluid leaking somewhere internally. I just don't know what else to try, I'm stumped. I hope you guys can help me out with this one, I really don't want to bring it in to be fixed. Too expensive and I don't learn anything about how my bike works. Thanks in advance!

 

Ok. When you are bleeding the clutch, are you leaving the bleeder screw open? If you are, then that's your problem. You bleed the clutch or brakes by leaving the bleeder screw closed, pumping then holding the lever and opening the bleeder screw. Continuing til there's no air left. If this isn't the case, then try bleeding from the banjo bolt on the line at the master cylinder and the bolt at the slave cylinder.

 

Yeah, I've been bleeding like you said. Pump the clutch a couple times, hold it down and loosen the bleed valve, let fluid out, close it and release clutch. I'm not getting any air bubbles tho.

I'm still kinda new to repair, what exactly is the banjo bolt, and by master cylinder do you mean reservoir?

 

The banjo bolt is the one at the reservoir (where the master cylinder resides) where the line bolts up.
Sometimes air gets traps there and is hard to bleed out.
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Some thoughts...
1. Squeeze the clutch lever a few times to make sure the master cylinder is fully bled.
2. You shouldn't have to open the banjo bolt, though air can get trapped in there. If you do open the banjo bolt, you will have to replace the crush washers.
3. After you've flushed the line, crack the bleed valve open without touching the clutch lever. This will gravity bleed the slave cylinder and displace any air that snuck in around the threads.
4. It's possible air is entering through the clutch slave cylinder, which will need a rebuild.

 

I've bled many a clutch and brake systems and have had to bleed the lines. And you don't have to replace the washers. It may be a good idea, but it's not necessary

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Thanks guys. I just found some info on bleeding from the banjo bolt here. I did everything laid out in those instructions. first cracking the bold and letting some fluid bleed out. That worked ok but my clutch was still loose. So I took the bolt all the way off and bled using my finger over the hole. Lots of pressure there, put the bolt back on while holding down clutch, still no pressure.

I tried bleeding out of the main bolt on the slave cylinder afterward, lots of fluid comes out after having the clutch held down, no air. Repeat a few times, still no pressure on clutch.

I made this video to clarify where I'm at. Anthing else I can try? Do you guys know what may be going on? Do I still have air in the system somewhere? I've gone through quite a bit of DOT 4 brake fluid so far, and I was planning on doing my brake fluid too...

[video=youtube;BYa9Pv-m3bg]https://www.youtube.com/watch?v=BYa9Pv-m3bg[/video]

 

Is there a possibility that when you put the slave cylinder back together that you didn't get it together correctly? Maybe the seal on the piston is damaged?

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That is possible, and I was just thinking that. I just took it back apart and snapped a pic (below). It seems like it really only goes together one way, there isn't too many parts. And the seal seems tight, its not cracked or dry. Also there was no fluid outside the cylinder when I took it off.

One thing I did notice that seems odd is that the rod going into the crankcase is pushed in as far as it will go (by hand), the bike is in first, and the wheel is still locked. Unless I'm mistaken how the clutch works, doesn't the fluid get pumped into the cylinder, forcing it outward (in towards the bike) pushing the rod into the crankcase releasing the gears. If the rod is in as far as it will go and the wheel is still locked, thats bad right?

 

The rod seats into a joint that pushes the clutch plate releasing tension on the clutch discs allowing the gear changes. The clutch rod aught to be out almost flush with the outside of the case where the gasket is. It's hard to tell from the pic how far out it is. If it is pushed in all the way to the case, then yeah, that's not good.

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The rod is pretty much flush with the gasket. Seems ok, I was just wondering about why I can't push it in by hand and release the tension on the clutch discs to allow me to spin the wheel when in 1st gear.

I've bled the system about 5 times now, checked the functionality at the banjo bolt (good), the master bolt in the slave cylinder (good), and pretty sure I've gotten all the air out. Still no luck. Clutch is still soft, and innefective.

In the troubleshooting section of the manual it says for soft or spongy clutch it could be air in the hydralic system, low fluid level, or leaking. Pretty sure it's not any of these. I'm stumped. I just wanna get my bike back up and running!

 

You aren't going to be able to push the rod in by hand. You could try getting a large syringe filled with brake fluid , hooking a tube to it and opening the bleeder at the slave cylinder and pushing the fluid through the system backwards. I've seen it before and it sometimes works.

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Not to sound unappreciative, but what does that accomplish? I'm pretty sure I have fluid throughout the system, with no air. It just doesn't seem to compress enough fluid into the cylinder before it cycles it back into the reservoir.

I'm willing to try that if I can find a syringe, I'm just curious as to what it does.

 

It eliminates the need to constantly pump the lever and if there is any air still trapped, then usually it will push it out. I know you think you've gotten all the air out, and you may have, but I've been in the same situation bleeding for thousand times, only to still have air in the system. You either still have air, or the slave cylinder has something wrong with it as that's the only thing that came apart. Other than that, IDK.

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Cool, I'll give that a shot when I get back home. Hope I can find a syringe.

 

The reason for using a syringe on the bleeder is because it will push the air bubbles up easier than trying to push them down and as you say there was no fluid in the slave cylinder when you pulled it apart, I have to ask why. Also in the vid I can't see what you are doing with your left hand, you need to pump and hold while you undo the bleeder, close the bleeder and then release the lever. There is no pressure showing when you open the bleeder it should squirt 6 inches out. Also be careful with that bleeder you are tightening it too hard and you could break it off. Also remember to be very careful with brake fluid and paint, don't touch any paintwork with fluid on your hands

 

does'nt hurt to have a bottle with H2O in it incase you accidently spill some DOT4 on your paint/garage floor. Water nuetralizes it. You could always invest in a air bleeder too, they hook up to your compressor and make fast work of these types of yabs.

Filling from the bleed nipple is a good trick btw. Think they do that in the aviation industry as standard practice. I used to have an oil squirt bottle filled with DOT4 for this specific purpose.

 

Filling from the bottom usually works when other methods have failed, but keep the top offf the master and a rag covering it.

Also, be very, very, very, very, VERY careful not to over-tighten the longest bolt that secures clutch slave to cover and bike !@!!!!!!!!!

 

Pretty strange that the clutch line is so difficult to bleed. If none of this works, the only other thing I can think of is that there is a worn seal on the slave cylinder that is letting air in when the clutch lever is released. You could try gravity bleeding the clutch line... that should displace any residual air without pulling in more air. If the slave cylinder seal is worn, gravity bleeding the clutch will give you normal initial clutch lever feel which will become spongy as air is pulled in.