Clutch master cylinder problem

[Mr.Frequent]

Yesterday after washing my '02 off I thought I would take a ride because I hadn't for months during this Covid pandemic.

It started fine, I rolled it off the center stand,and clicked into first gear.It died.
The problem is I have NO fluid pressure in the clutch master cylinder- so pulling the clutch doesn't disengage..

I bled and replaced the clutch fluid out through the factory lug last spring with no issues and good performance.There are no leaks,oily spots ,peeling paint or fluid lying on the bike or floor.
Filled the master cylinder and tried to bleed through the factory lug again , but I have no pressure or buildup and no clutch action.

What do I check, and in what order? This is the first problem I've had that isn't obvious as to a cause.

I appreciate comments from anyone who had the same situation or experiences.Gotta have one last ride before winter !

[riceburner]

I'm not that knowledgable about the clutch system, but.... if you're putting fluid in, and it's not coming out in a visible fashion (ie dripping out the back of the slave-cylinder) then it's coming out the FRONT of the slave-cylinder -ie - into the gearbox (or is there a tunnel? I can't remember). Either way - it's tear down time.

First thing to check though is that there is NO leaking ANYWHERE along the clutch hose, or out the 'bleed' hose.

Then it's time to get the tools out properly.

[Boxer]

Its been quite some time since I worked on my R1150R hydraulic clutch but If I recall correctly, the fluid bleed lug only bleeds the fluid through the line from the master cylinder to that lug. It doesn't bleed out the slave cylinder underneath the bike. I may be wrong on that, but riceburner is correct. That fluid in the slave cylinder has been known to follow along the spinning push rod right over into an area where it doesn't belong.
Cyclerob should join this thread soon, whenever he runs across it. But I agree with riceburner it is time to break out the tools and get that slave cylinder off to inspect it.

[Mr.Frequent]

Thanks Riceburner and Boxer.

My clutch master wasn't empty or even below the sight window when I found the problem so it may be the leaking slave hasn't let too much fluid go into the clutch or the cavity.I can pull the pushrod out and see if it's wet but I'm going to pull off the starter first chance and see if I can get a lookee maybe with a otoscope..
I'm sure I'll need a new slave cylinder.

My thoughts are if I don't have much leakage ( how will I know ? ) maybe I won't have to take the transmission out and replace the clutch.

I have also heard that the clutch system's DOT 4 will cause the transmission seals ( shaft seals or case seals ?) to disintegrate - I wonder if that's true ? ,or lore like the widely contentious idea that some model R bikes are eventually all going to have clutch splines strip?

I'm just trying to get a plan of action before I rip into it.

Appreciate the interest !

[Dgdecker]

I’m relatively new to bmw’s but If I recall correctly you need a special bmw fitting to properly bleed the clutch on the r1150r. If you didn’t use that the prior bleed may not have been effective. I’d double check that before tearing it apart.

[Mr.Frequent]

DG Decker , bleeding the clutch lines wasn't an issue, that went fine .

[AZBMWRIDER]

Does the fluid level go down in the master cylinder when you operate the clutch lever numerous times ??

[Mr.Frequent]

AZBMWRider, no the fluid level doesn't go down when I operate the lever. There isn't any pressure build up or leaking on the floor either. I'm waiting for a November warm up here in the midwest before I take anything else apart - otherwise I may have to wait 'til spring>I have an unheated garage.

[swamper]

Jacket

[Tundra Dweller]

One item to check is to bleed your master cylinder. If there was any air in the line it can rise and get stuck in the MC. Almost common after changing brake lines. Air in the MC would also make it feel useless.
Put a rag under the Banjo bolt on the MC. Just crack the bolt going into the MC then, while putting pressure on the lever slightly open the bolt until you have fluid leaking out around the the Banjo bolt. Watch for any air to come out and keep stroking the lever until you tighten the bolt. This can also confirm your Master Cylinder is still pushing fluid.
It might be you need new MC seals.
When I bled my Clutch with a Mity-Vac it worked fine. The following season I had clutch slip at peak power. Then did a manual bleed with a clear hose and got some small air bubbles, very little but that fixed it.

[Mr.Frequent]

Thanks, Tundra Dweller ,that's a good first step to try or at least eliminate as an issue.If it's not simple, I'll just have to wait.
Swamper . . ."Jacket" ? ?

Thanks everyone. I'll get back .

[CycleRob]

**** Portions of text Copy-n-Pasted from old posts: **(edited 12-24-20 to correct and add more descriptions)**
Bleeding the clutch slave is very easy, even with the entire system brand new clean, dry -and- with no special bleeding equipment available to you. What has to be understood is that air and air bubbles always want to float upward when submerged in liquids and trying to force tiny air bubbles downward to the bleeder hose can be an exercise in futility. Put the bike on the center stand, then pass a tie-down through the front wheel against the rim ID and connect each end hook to the center stand cross brace, effectively stopping the center stand from folding rearward after it is tightened up. With a helper, tilt the bike over enough, each way, to sequentially insert a one inch thick board under each center stand foot so that the rear wheel is about 3 inches (76+mm) higher than the front wheel. That front down tilted position (Remove the bags and trunk!) ensures that any air bubbles will go to the rear of the slave cylinder internal body, where the bleeder is located. Next, turn and tie-down secure the steering to the right steering stop, effectively orienting the tiny bleed back hole at the bottom of the Master Cylinder (MC) so it is now higher than the attached Banjo bolt line fitting. Then you fill the empty MC reservoir to 3/4 full from the reservoir's top opening "spill over low point" and open the bleeder with an attached bleeder hose inserted into a container. Now, if the MC is clean and the lever free-play is adjusted properly, it should (VERY) slowly partially drain into the slave chamber by gravity. It also may not. That is when you SLOWLY squeeze the lever in, so the ball end travels less than an inch (25mm) until minute pumping resistance is first felt, and fully out, 7+ times, to purge tiny air bubbles out the MC reservoir's tiny bleed back hole. Then try a bleeding routine, pumping mostly air out the bleeder, with different pause times:

1--Open bleeder.
2--Squeeze lever to bar and hold 5 seconds. That allows the air in the slave to go uphill toward the bleeder.
3--Close bleeder.
4--Release lever quickly and wait 5 seconds.
5--Repeat to step 1 until you get full slave piston working travel.

Those 5 second wait times allow very low pressure air to move thru small bleeder fitting openings. Watch the reservoir fluid level and use the rectangular lid's attached rubber bellows to cap any lever induced upward fluid spurts. Once you feel resistance that shows the clutch is releasing, it says that most of the air has been expelled. Do this:

1--With the steering held to the right steering stop, bleeder closed, slowly squeeze the clutch lever to the bar.

2--Release lever quickly and wait 5 seconds for air bubbles to combine

3--Cycle the clutch lever in-n-out within the very short freeplay zone before pumping pressure starts 5+ times, to allow any hidden air bubbles to go Up-n-Out the MC reservoir bleed back hole. You will see them bubbling up thru the liquid until steps 1 to 3 generate less and less air bubbles until there are none . . . only liquid moves the standing fluid's top surface.

4--Bleed the slave cylinder like this:
a--Squeeze lever to the bar and hold it there.
b--Rapidly open bleeder then close it.
c--Release lever then repeat from step (a).

5--Using the bleeder to cycle the slave piston in-and-out helps purge air and older trapped fluid.

6--When air bubbles stop, you are done!

Some thumbs for you to load pics for clarification.


****If the proprietary factory black anodized Aluminium bleeder assembly has not been removed you need to do this:
The bleeder fitting you need is a BMW part number that I believe fits an older model BMW rear brake caliper. It replaces the entire factory proprietary bleeder check valve assembly screwed onto the spinning hex nut end of the bleeder line. To prevent the reservoir fluid from siphoning while you disconnect things, hold the clutch lever partially depressed with a rubber band, or better yet use the square cross section rubber gasket from a used oil filter. BTW that factory bleeder assembly has (semi permanent) red Loctite on the threads attaching it to the bleeder line. That Red epoxy needs a fast high heat Propane torch application to soften it to a gooey paste so you can loosen it. The heat needs to be applied quickly and focused on the bleeder body close to the fitting so the heat is not conducted into the plastic and rubber part of the bleeder line. I used a 10" ViseGrip's intentionally HARD bite-mark-leaving-grip to hold onto the free end of the black painted Aluminium body of the (expendable) factory bleeder -AND- an 11mm flare nut wrench on the bleeder line nut to loosen it. If you use an open end or adjustable wrench on that nut you will end up crushing it out of shape . . . then it may crack during attempts to true it up again and/or will not work well with the new bleeder fitting. I used a very wet rag wrapped around the line, touching the flare nut wrench mounted on the hex nut fitting and then used the tip of the inner blue flame to hit the Aluminium cylindrical bleeder near the line nut fitting for about 8 seconds. Put down the torch and try to loosen the nut with the flare nut wrench while holding on tightly to the attached ViseGrip. If it does not loosen, quickly add another 4 seconds of heat and try to loosen it again.

When you obtain the new fitting, lightly grease the male threads to lessen the chance of galling the Aluminium threads after many loosen-tighten-loosen sequences as you bleed the slave. Use very low torque when you tighten the bleeder during the bleeding process and medium torque for the final one. Be very aware that greasing the threads LOWERS the torque required by about 30 percent to obtain the proper torque . . . so do NOT over-tighten a greased fitting! After bleeding, squeeze-and-hold the clutch lever for a minute plus to check that the solvent cleaned bleeder opening is not leaking DOT4 fluid.

[Mr.Frequent]

Thanks so much,CycleRob.
I've read many of your posts( the most informative and detailed in this forum) and will try your methodology when I get a warm-up day.Too cold here in the Midwest to ride or fix just now,and have a family member with health issues right now..

I haven't pulled the starter to look in at the clutch plate to see if it's wet with fluid,that was going to be my starting point; I have no fluid leaks I can find but suspected the slave leaking first.
The clutch lever just pulling easily down to the grip one day without pressure, previous problems or issues really confused me.One more point: is this partially copied from a front brake bleed ? I ask because of the mention of the brake light microswitch on the clutch lever.. I can see where the idea is the same, just need clarification so I don't further confuse the myself.
Thanks for taking the time to help!

[CycleRob]

Mr.Frequent,
Yes, the idea is the same and that dry start fluid charge procedure was taken from the front brake M/C write-up and it slipped by me in the procedural transfer. Actually, the clutch lever switch does not click until the lever is pulled almost to the bar-grip, so the starter will work in gear.
I'll change it by saying "squeeze the lever so the ball end travels less than an inch (25mm) and you feel a slight pumping resistance".

[Mr.Frequent]

I thought so and thank you so much.

[Mr.Frequent]

My apologies to all for such a long length of time passing.

" Put the bike on the center stand, then pass a tie-down through the front wheel against the rim ID and connect each end hook to the center stand cross brace, effectively stopping the center stand from folding rearward after it is tightened up. With a helper, tilt the bike over enough, each way, to sequentially insert a one inch thick board under each center stand foot so that the rear wheel is about 3 inches (76+mm) higher than the front wheel."

Turned the bars right, and made the master cylinder the highest point -This worked.

With enough time, the air worked it's way up .I got *some* pressure back after letting the bike set through the cold months , so I re-bled the clutch and it works perfectly now. There is a proper bleeder installed where the useless BMW aluminum factory grub screw was.
Glad I didn't start tearing it down and replacing parts.
Thanks, CycleRob .