clutch output cylinder installation question

[steve68]

02 R1150R w/ 49,750 miles.  In November '22  I lost clutch resistance and function, found old corroded clutch fluid in the master cylinder.  Figured the output cylinder failed.

 

Got a new output cylinder, friction plate with longer splined hub.

 

Split the bike, cleaned out the muck, installed new output cylinder and friction plate, reassembled pretty smoothly.  (no, I did not add the weep hole which would have been smart...)

 

Anyway, now it is taking FOREVER to get the cluth circuit flushed and air-free.  Wondering if I missed anything on the reassembly.

 

Specifically, when I cleaned out the output cylinder seat in the rear of the transmission, there was a ton of stuff caked in there, but no discernable seal or gasket, and no mention of one in any of the resources I looked at (YouTube, Clymer) so I did not install one.  now I am wondering if there was supposed to be a gaset in there and I am lacking a seal in there.  I know that does not make a ton of sense because if air could get in, fluid should be coming out...

I know this is a long shot but thought I'd ask.

 

Maybe I just need a better way to bleed the circuit.  I don't like the speed bleeder, seems to seep a lot of clutch fluid from around the threads.

 

Thanks for reading this,

Steven

[dirtrider]

17 minutes ago, steve68 said:

02 R1150R w/ 49,750 miles.  In November '22  I lost clutch resistance and function, found old corroded clutch fluid in the master cylinder.  Figured the output cylinder failed.

 

Got a new output cylinder, friction plate with longer splined hub.

 

Split the bike, cleaned out the muck, installed new output cylinder and friction plate, reassembled pretty smoothly.  (no, I did not add the weep hole which would have been smart...)

 

Anyway, now it is taking FOREVER to get the cluth circuit flushed and air-free.  Wondering if I missed anything on the reassembly.

 

Specifically, when I cleaned out the output cylinder seat in the rear of the transmission, there was a ton of stuff caked in there, but no discernable seal or gasket, and no mention of one in any of the resources I looked at (YouTube, Clymer) so I did not install one.  now I am wondering if there was supposed to be a gaset in there and I am lacking a seal in there.  I know that does not make a ton of sense because if air could get in, fluid should be coming out...

I know this is a long shot but thought I'd ask.

 

Maybe I just need a better way to bleed the circuit.  I don't like the speed bleeder, seems to seep a lot of clutch fluid from around the threads.

 

Thanks for reading this,

Steven

Afternoon Steven

 

There is a gasket between the slave cylinder & the transmission case but that has nothing to do with air entering the system or fluid leaking out.

 

Did you pre-bleed the clutch master on the handlebars? If not that is probably where your air is coming from.

 

If it is already assembled then you can pretty well bleed the master cylinder by removing the cover, making sure the reservoir is abut 3/4 full. Then slowly & lightly move the hand lever, not very far & not very fast, just a 1/4 inch or so. Look into the reservoir when moving the lever to see if air bubbles are working their way up & out of the take-up port in the bottom of the reservoir. (Caution do not move the lever fast or far as that can squirt fluid up & out of the reservoir). Brake fluid on your paint or dash can ruin them.

 

Once the bubbles stop coming up then fill the reservoir, then either put the cover back on. Or leave the cover off but just toss a clean quarter (or clean carpet knife blade) in the bottom of the reservoir to prevent fluid from squirting up & out while bleeding. 

 

[steve68]

When you say "pre-bleed the master on the handlebars" do you mean prior to securing the line from the master to the new output cylinder?  I did NOT do that.

 

Yes, I have been seeing tiny bubbles come up in the master cylinder so you may be correct.  Good to hear I don't need that gasket cause I do NOT want to go back in there to put one there.

 

I'll try your recommendation.

 

Thanks so much for the quick response.

[steve68]

New issue.

 

Background:  Purchased this 02 R with now 50K miles when it had 20K miles on it.  I was completely negligent in changing the clutch fluid prior to the output cylinder failing me in November 2022.  At that time the clutch fluid had become a black thick oily goo that I could only flush out by administering a bolus of fresh fluid via the clutch bleed screw.  More black goo flushed up into the clutch fluid reservoir which I sucked out and discarded.  Then I took everything apart and replaced the output cylinder and the friction plate.

 

Current issue:

 

Now, when I first head out for a ride, clutch feels good, good resistance in pulling the lever, easy to engage letting the lever out.  Then, over course of a few hours, seems like I need to let the lever out further and further to fully engage the transmission, and starts to feel rumbly.

Wondering if the above mentioned black oily goo may have damaged the piston in the clutch master cylinder and it becomes sluggish as I am out riding.  I do have an old brake master cylinder that I can pull the piston from and change it.  I really can't think of anything else.  Pretty sure I installed the output cylinder and the friction plate correctly.  When I am riding, acceleration is good, there is no strange vibrations.

 

Any help appreciated.

 

Steven

[dirtrider]

31 minutes ago, steve68 said:

New issue.

 

Background:  Purchased this 02 R with now 50K miles when it had 20K miles on it.  I was completely negligent in changing the clutch fluid prior to the output cylinder failing me in November 2022.  At that time the clutch fluid had become a black thick oily goo that I could only flush out by administering a bolus of fresh fluid via the clutch bleed screw.  More black goo flushed up into the clutch fluid reservoir which I sucked out and discarded.  Then I took everything apart and replaced the output cylinder and the friction plate.

 

Current issue:

 

Now, when I first head out for a ride, clutch feels good, good resistance in pulling the lever, easy to engage letting the lever out.  Then, over course of a few hours, seems like I need to let the lever out further and further to fully engage the transmission, and starts to feel rumbly.

Wondering if the above mentioned black oily goo may have damaged the piston in the clutch master cylinder and it becomes sluggish as I am out riding.  I do have an old brake master cylinder that I can pull the piston from and change it.  I really can't think of anything else.  Pretty sure I installed the output cylinder and the friction plate correctly.  When I am riding, acceleration is good, there is no strange vibrations.

 

Afternoon Steven

 

You would think a damaged master cylinder piston (cup) would allow the clutch to engage earlier rather that later in the hand lever stroke. 

 

No way to know anything for sure without actually riding it but as a rule a little air still trapped in the system can expand when hot giving a slightly later release in the lever stroke when hot.  

 

You might try getting the front end up as far as possible, like real steep driveway or very steep hill (way way up not just a little) then pull the cultch lever and allow it to snap release (do this a number of times). This can allow any trapped air into system to migrate up & out into the master cylinder reservoir.

 

You didn't overfill the clutch reservoir did you?  That can also hinder clutch release. 

[steve68]

6 hours ago, dirtrider said:

You would think a damaged master cylinder piston (cup) would allow the clutch to engage earlier rather that later in the hand lever stroke. 

 

I was thinking that the piston would slide ok when pushed by the lever but then be sluggish to return under pressure from the spring if the cups were damaged.  Make sense?

 

6 hours ago, dirtrider said:

You didn't overfill the clutch reservoir did you?  That can also hinder clutch release. 

How would this hinder clutch release?  I don't believe I overfilled.

 

thanks again

[dirtrider]

12 hours ago, steve68 said:

I was thinking that the piston would slide ok when pushed by the lever but then be sluggish to return under pressure from the spring if the cups were damaged.  Make sense?

 

How would this hinder clutch release?  I don't believe I overfilled.

 

thanks again

Morning steve68

 

I was thinking that the piston would slide ok when pushed by the lever but then be sluggish to return under pressure from the spring if the cups were damaged.  Make sense?---  You would probably feel the excessive lever free-play as you pulled the lever if the piston was sticking 

 

How would this hinder clutch release?  I don't believe I overfilled.--- The clutch master cylinder reservoir fluid is not directly vented to atmosphere. The rubber bellows in the cover above the fluid level moves as the fluid level goes up & down. If it is over-filled then the rubber bellows can not move far enough before contacting the cover  so the  reservoir  retains some positive pressure. 

 

On the BMW hydraulic clutch, the fluid level in the master cylinder reservoir actually rises as the clutch disk wears (or as a new clutch disk seats in & becomes slightly thinner). 

[steve68]

Thanks so much for the quick and clear explanation. 

1 hour ago, dirtrider said:

If it is over-filled then the rubber bellows can not move far enough before contacting the cover  so the  reservoir  retains some positive pressure. 

I did notice that the problem seemed to get a bit better after just removing and theh replacing the reservoir cover.

 

1 hour ago, dirtrider said:

the fluid level in the master cylinder reservoir actually rises as the clutch disk wears

This makes total sense since a thinner disk results in greater spring movement against the pushrod --> output cylinder --> fluid level in reservoir.

[steve68]

So I went out and tried this.  

On 6/3/2023 at 12:44 PM, dirtrider said:

You might try getting the front end up as far as possible, like real steep driveway or very steep hill (way way up not just a little) then pull the cultch lever and allow it to snap release (do this a number of times). This can allow any trapped air into system to migrate up & out into the master cylinder reservoir.

Tried this today.  I also removed my GS hand guards and rotated the clutch line banjo bolt back down  to it's original position thinking it may be trapping air in the portion of the line that is higher than the piston.

 

I also flushed out some of the reservoir fluid to make sure it is not overfilled.

 

The clutch felt better after the hill procedure.  Not sure if that is THE fix, but good enough to ride for a while and see.  The resistance when pulling the clutch lever in still feels less that I am used to ....