Ducati Monster Forum

Moto Board => Tech => Topic started by: JimmyTheDriver on June 04, 2012, 08:09:20 AM

Title: S4R - Clutch Lever Went Completely Limp
Post by: JimmyTheDriver on June 04, 2012, 08:09:20 AM
Hey fellas,

*Edit* This all started since I moved the bike in the back of a moving truck a month ago.  I know the level was knocked slightly upward by a box and I pushed it back down.

Over the past few weeks, the clutch pull on my 2007 S4R has gotten pretty tough.  I noticed my hands getting sore after a few blocks.  It felt like there was a good bit of friction in the lever and a squeak coming from both the lever/master and potentially the slave.  Thinking I knew what do do, I popped the lever off the master assembly, and am now left with an inoperable bike.  When I took it off, I cleaned off some of the dirty grease, added a small bit, and tried to put it back in.  The little push pin wouldn't set in the rubber boot all that well, and eveything just looked... weird.  Once I thought I had it re-assembled, there was no pressure on the lever and the bike was unable to shift.  The rubber boot looked pressed in.

Is there a trick to this?  Do I need to bleed?  I literally know nothing about this assembly (lever, master, slave) so any advice would be great.

If it helps...
(http://i.imgur.com/TCqn8.jpg)

Thanks
Jim
Title: Re: Clutch lever/slave issues, squeak, hard pull
Post by: JimmyTheDriver on June 06, 2012, 06:03:23 AM
Bump to get a bike on the road!
Title: Re: Clutch lever/slave issues, squeak, hard pull
Post by: ducpainter on June 06, 2012, 09:37:09 AM
It looks like the piston is stuck in.

Where is the boot?
Title: Re: Clutch lever/slave issues, squeak, hard pull
Post by: ducatiz on June 06, 2012, 09:49:30 AM
i would disassemble it to make sure the seals/piston are good.  the pistons can rust and there is a return spring too.

lube it all up well with brake assembly lube and try again. 
Title: Re: Clutch lever/slave issues, squeak, hard pull
Post by: thought on June 06, 2012, 11:25:03 AM
Anytime there is something wrong with the clutch or brake feel I always bleed first.  Most times it fixes the issue and after that I start thinking about how much it's going to cost me if that didnt fix it.

Not sure what else do after that doesnt work though.
Title: Re: Clutch lever/slave issues, squeak, hard pull
Post by: JimmyTheDriver on June 07, 2012, 05:55:28 AM
Quote from: ducpainter on June 06, 2012, 09:37:09 AM
It looks like the piston is stuck in.

Where is the boot?

The boot is in the pic.  Maybe this one is better?

(http://i.imgur.com/ffnMU.jpg)

When I try to reassemble and pull in lever, there is no friction until the lever is virtually touching the grips, and then the boot is extremely squished in there.

Maybe Ill go the bleed route first.  How tough is the complete dis assembly?  Anything to keep it out of the shop.

-Jim
Title: Re: Clutch lever/slave issues, squeak, hard pull
Post by: ducpainter on June 07, 2012, 02:18:18 PM
Yeah...

that looks better.

It makes no sense that it would work and then suddenly not work just because you removed the lever.

I guess bleeding is in order.
Title: Re: Clutch lever/slave issues, squeak, hard pull
Post by: ducatiz on June 07, 2012, 02:30:20 PM
Quote from: JimmyTheDriver on June 07, 2012, 05:55:28 AM
How tough is the complete dis assembly?  Anything to keep it out of the shop.

-Jim

that's a small bolt/ axial master right?

everything comes out that hole -- a snap ring holds it in.  they are plain type, hard(er) to get out.  i swapped mine with the standard type so i can use a pin tool.

once you take the ring off, you push a pin thru the banjo bolt hole and push everything out.  you can't really hurt the base of the piston unless its a plastic version (later ones are plastic).  the seals on on the piston itself and there is a spring behind it.

i use brake assembly lube, the silicone grease stuff, and lightly cover the spring and piston and slather it on the orings.  the grease will remain in place to reject moisture over a longer time than not being covered. it has to be a very thin coating tho.

Title: Re: Clutch lever/slave issues, squeak, hard pull
Post by: JimmyTheDriver on June 23, 2012, 02:20:07 PM
So I went to bleed today, using instructions in the link, and am stumped.

http://www.speedzilla.com/forums/ducati-supersport/3431-clutch-bleeding-tips.html#post26375 (http://www.speedzilla.com/forums/ducati-supersport/3431-clutch-bleeding-tips.html#post26375)

Below is what I see... I don't have anything to "push in" on the slave and what I thought was the piston is stuck in the clutch assembly, not attached to the slave.  Does anything look out of whack here?  Also noticed the rubber on the master is cracked.  The clutch lever has absolutely no pressure behind it.

(http://i.imgur.com/88tJz.jpg)
(http://i.imgur.com/Ti5RO.jpg)
(http://i.imgur.com/3So4t.jpg)
Title: Re: S4R - Clutch Lever Went Completely Limp
Post by: Slide Panda on June 23, 2012, 04:06:21 PM
There's a piston in there you'll just need something to push it in with. You can draw the push rod out carefully and use it to push the slave piston back in
Title: Re: S4R - Clutch Lever Went Completely Limp
Post by: JimmyTheDriver on June 23, 2012, 05:23:15 PM
Appreciate the help!

It just looks like a hole.  There is something to push in there?  I stuck a screwdriver point in there to try and push whatever it is, in... felt like I almost hit the back of it.  Push harder?

When you say push rod, you mean the rod sticking out of the engine?  I tried to give it a grab.  The only movement it has is that it can spin.  How does it come out?

Thanks!
Jim
Title: Re: S4R - Clutch Lever Went Completely Limp
Post by: Slide Panda on June 26, 2012, 09:10:32 AM
Yes, the rod coming out of the engine. It simply passes through to the pressure plate and inserts to a sleeve that in turn inserts to the bearing in the center of the pressure plate. You should be able to draw it out with minimal tugging. THough if you have an open clutch, they can get cruddy and bound up. Happened to my 900.

If That's the case you can open up the clutch side and remove the pressure plate and pull it out that way. If you do that, take the time to check the bearing on the pressure plate, they do need replacement from time to time. Some penetrating oil (Deep Creep, PB Blaster etc) and a soak should help free the push rod. Nothing like a screw holds it in place, it's just a light press fit.

Wtth the rod, you should be able to push the piston back into the slave - given that it's not already all the way in. It may help to open the bleeder when pushing to ensure the system is not locked up. Just be ready for the mess if you don't have a hose connected.

The hole you can see from the outside is a pass through to the slave piston that moves when you pull the clutch lever. Pulling the lever forces fluid into the slave pushing the piston -> push rod-> pressure plate -> springs. When you release the lever the springs push -> pressure plate -> push rod -> slave piston and fluid moves back up to the master.
Title: Re: S4R - Clutch Lever Went Completely Limp
Post by: JimmyTheDriver on July 02, 2012, 06:09:56 AM
Thanks Slide Panda -

Got it all bled and it works again.

The slave still has a horrid squeek.. feels like it's going bad, but I'm starting a new thread for that.

Thanks again,
Jim
Title: Re: S4R - Clutch Lever Went Completely Limp
Post by: Slide Panda on July 02, 2012, 06:55:47 AM
Cool.  Was probably something like an air bubble that formed from tiny ones into one big one that was up in the master blocking normal fluid paths. Happens from time to time.

My rule on clutch issues in the absence of any obvious external cause - bleed the hell out of it, strap the lever to the bar over night and see whats what the next day.
Title: Re: S4R - Clutch Lever Went Completely Limp
Post by: JimmyTheDriver on July 02, 2012, 07:51:07 AM
Yep, I did basically that.

1) Opened pee cup
2) Detached slave from motor
3) Put rubber tube on slave bleeder and put end of tube in bottle
4) Opened slave valve (never had to open master valve)
5) Used clutch push rod to push slave piston all the way in
6) Filled pee cup with dot4 and kept it full throughout the process.  If it hits bottom, air will be introduced and have to start over
7) Pumped clutch lever over and over and over and over, each pump pushed oil through the lines and out the valve on the slave
8) Used almost a full bottle of dot4 to make sure I pushed most air out
9) Strapped clutch lever to bar and let sit for 8 hours.  Within seconds of it being held there, tons of additional air came out valve
10) Tapped entire system with end of screwdriver to knock out any additional bubbles
11) Closed pee cup
12) Closed slave valve

Thanks!
Jim
Title: Re: S4R - Clutch Lever Went Completely Limp
Post by: Slide Panda on July 02, 2012, 07:56:44 AM
For next time - you've also got the very handy bleeder on the master.
Title: Re: S4R - Clutch Lever Went Completely Limp
Post by: Armor on July 02, 2012, 10:05:20 AM
Next time just leave the slave on the bike and bleed it.  Much easier.
Title: Re: S4R - Clutch Lever Went Completely Limp
Post by: JimmyTheDriver on July 02, 2012, 10:37:46 AM
Quote from: Armor on July 02, 2012, 10:05:20 AM
Next time just leave the slave on the bike and bleed it.  Much easier.

Good idea.  The real reason I took it off is to try and get rid of a squeak by throwing some grease in there but that did't work, hence the new thread.

http://www.ducatimonsterforum.org/index.php?topic=58230.0 (http://www.ducatimonsterforum.org/index.php?topic=58230.0)

Thanks,
Jim
Title: Re: S4R - Clutch Lever Went Completely Limp
Post by: ducatiz on July 02, 2012, 11:07:39 AM
Quote from: Armor on July 02, 2012, 10:05:20 AM
Next time just leave the slave on the bike and bleed it.  Much easier.

i've actually found it easier to take the slave off, use a c clamp to block the piston and elevate it.  air bubbles float upwards.

Same practice for underslung rear calipers. 

i've also used a small vibrating child's toy attached to the line which vibrates the bubbles up, but of course will get further ridicule for that one.  but it works like crazy. 
Title: Re: S4R - Clutch Lever Went Completely Limp
Post by: koko64 on July 02, 2012, 04:10:55 PM
Hey Tiz, I tried your idea and it worked well. [thumbsup]
I had old buzz hair razor/clippers and removed the blades. I taped it to the lines and it really did vibrate the tiny bubbles off the line inners. It's a special bleeding tool now. Got that final bit of air out.
Title: Re: S4R - Clutch Lever Went Completely Limp
Post by: ChchS4 on July 20, 2014, 07:56:07 AM
hi: I found this thread via Google when I encountered the same problem. I removed the stock clutch lever to replace it with an aftermarket version and the "S4R-Clutch Lever Went Completely Limp" - the title of this thread described my situation precisely.  My approach to fixing it differed slightly so I am adding this to the very useful knowledge based kept on this forum.

After reading a lot and watching a lot of Youtube videos I chose to buy a "Mityvac".  I used this tool to flush the clutch line, leaving the slave on the bike.  So after replacing the old fluid with nice new fluid, and there were no more air bubbles emerging, the clutch lever remained as limp as ever.  I did this a couple of times but nothing changed.

Next I unbolted the slave and tried again. This was a lot of trouble but also had no effect on limpness.  Someone in the thread suggested that this step is unnecessary and I agree. If you think about it, taking the slave off and pushing the plunger all the way back recreates the same situation as if the slave is still bolted on the engine.

So next, I tried bleeding the vent on the master cylinder with the Mityvac. Voila, all is good.

Next time, I will also use an old electric toothbrush to vibrate the lines.