Hydraulic Clutch - R1150RT

[PaulM]

My 2002 R1150RT is getting air in the clutch line. Bleeding it fixes it for a little while then it comes back. I see NO leaks at all. Has anyone ever seen this? I was thinking about replacing the plunger and seals in the master cylinder. A $60 part verses $320 for a new master cylinder. Then again could it be the other device that bolts to the transmission?

[Kenny2]

Paul,

Mine was leaking and the unit was replaced when the splines were rebuilt.

 

I had a Jeep that the inner seal was bad, never lost fluid but it bypassed the plunger (at the slave) verse disengaging the clutch, especially when HOT.

[Paul Mihalka]

You may have a leaking slave cylinder at the back of the gearbox. If that leaks, the fluid runs along the clutch release pushrod and very soon it gets onto your clutch. Then you will also need a new clutch.

[RFW]

My 2002 R1150RT is getting air in the clutch line. Bleeding it fixes it for a little while then it comes back. I see NO leaks at all. Has anyone ever seen this? I was thinking about replacing the plunger and seals in the master cylinder. A $60 part verses $320 for a new master cylinder. Then again could it be the other device that bolts to the transmission?

This has NOTHING to do with the master cylinder. The piston seal on the master cyclinder has fluid on BOTH sides of it. Air can NOT leak past the master's piston seal, because there is no air anywhere near it.

 

Your problem is typical of a worn SLAVE cylinder piston seal. The piston seal on a worn slave seal WILL admit air. This can be seen if, when bleeding the system, the air comes out almost immediately. If it were the master (which it cannot be), the air would requires some pumping to work its way down to the slave and be expelled.

 

Bob.

[Karl]

I suspect that I am having similar problems. What are your symptoms? On mine, the clutch engages at just a slight release of the clutch after having the handle fully pulled back.

 

I just bleed the line, but I haven't noticed any difference.

[Paul Mihalka]

All you guys with hydraulic clutches and mushy clutch levers that start engaging close to the handlebar, more than likely have a bad slave cylinder. If that is the case, the hydraulic fluid WILL leak into the clutch and you WILL need a new clutch. Replace the slave cylinder NOW. If you take it to the dealer, try to get a trailer or pickup. It's cheaper than replacing the clutch. I may sound alarmistic, but it is just facing reality. And yes, I would prefer a cable operated clutch.

[David_Charlton]

Hi Paul,sorry to Hi-Jack the post but I've just changed the clutch fluid on my '03RT and noticed nearly black stained fluid emerge on the first squeeze, it then became clear, no air, just fluid, albeit dirty,do I need to worry? It's been 12 months since I last flushed it.

[Paul Mihalka]

I think as long as your clutch lever action feels normal you should be OK.

[SAAB93driver]

What kind of life are people seeing with the slave cylinder or is it all over the place?

 

Would holding in the clutch at red lights tend to shorten the life of the slave cylinder?

[Paul Mihalka]

Slave cylinder life is all over the place. What apparently really happens most of the time is that the clutch throwout bearing is enbedded in the slave cylinder unit and when the bearing goes it takes the seals with it.

In theory holding the clutch at a red light or a lot of stop and go traffic will shorten it's life. It puts pressure on the throwout bearing for longer times.

[PaulM]

The symptoms are a spongy feeling clutch, very little clutch or no clutch at all. My RT has 92K miles. After reading the replies I have purchased a new slave cylinder and plan on replacing it this weekend. Its a $121 part. Somewhere I read that it can be replaced without removing the swingarm. I went ahead and got a new plunger and seals to rebuild the master cylinder from Eurotech at a cost of $60. I learned BMW only sells a complete master cylinder at $350. The slave cylinder should fix it.

[SAAB93driver]

I've decided to buy a spare just in case. Looks small enough to carry on a trip.

 

In any case, if one pulls the slave cylinder back from the transmission and the cylinder is not covered and the clutch is actuating OK otherwise is this a good check? Can it be done without opening the hydraulic system?