Clutch slave cylinder longevity

[RogerC60]

I have a 2003 R1150RT with about 68000 miles on it. I'm fairly certain it has the original clutch slave cylinder. So far there is no indication of any problem with the clutch or input shaft splines, so I'm thankful for that.

 

Folks on this forum have had slave cylinder failures at 55000 miles or less. Others post here that an original slave cylinder with 100,000 miles on it is long overdue for replacement. Based on this I'll probably look into inspecting and probably replacing mine soon.

 

But nowhere have I found anybody talking about replacing the replacement slave cylinder. Is it just the OEM slave cylinder that wears out so quickly, or will the replacement slave cylinder also have the same short lifespan? After replacing the OEM slave cylinder should things be good for the rest of the life of the bike? Or should I be looking at replacing it every 60000 miles?

 

[dirtrider]

19 minutes ago, RogerC60 said:

I have a 2003 R1150RT with about 68000 miles on it. I'm fairly certain it has the original clutch slave cylinder. So far there is no indication of any problem with the clutch or input shaft splines, so I'm thankful for that.

 

Folks on this forum have had slave cylinder failures at 55000 miles or less. Others post here that an original slave cylinder with 100,000 miles on it is long overdue for replacement. Based on this I'll probably look into inspecting and probably replacing mine soon.

 

But nowhere have I found anybody talking about replacing the replacement slave cylinder. Is it just the OEM slave cylinder that wears out so quickly, or will the replacement slave cylinder also have the same short lifespan? After replacing the OEM slave cylinder should things be good for the rest of the life of the bike? Or should I be looking at replacing it every 60000 miles?

 

Morning  RogerC60

 

When it comes to slave cylinders it is basically a crap shoot. 

 

Some fail early, some go life-of-motorcycle, others start to seep a little long before they fully fail.

 

One of the big failure points is the pushrod bearing (basically a throwout bearing), when that part starts to go bad it pollutes the piston bore with old grease so that then ruins the actual clutch fluid seal.

 

That bearing basically spins most of the time that the engine is running  but unless the clutch lever is pulled in it rotates under almost no load.

 

Lots of stop & go riding, sitting at stop lights,  lots of clutch lever pulled in time is definitely harder on that bearing. 

 

Plus a lot of slave cylinder failures are due to not flushing/bleeding the clutch hydraulic circuit on a regular basis. 

 

Long motorcycle storage with older (moisture containing) clutch (brake) fluid also tends to shorten the slave cylinder life.

 

A good place to start is to replace the slave cylinder,  then slot the slave cylinder gasket on the bottom (or drill a drain hole in the transmission  case), then go to a once a year clutch system bleed doing it just before motorcycle storage if you live in an area that requires motorcycle storage through the cold winters. 

 

Once you replace the slave cylinder, then slot the gasket (or drill the drain hole) you then need get in the habit of looking for any signs of seepage at the drain location every time that you check your oil sight glass (or on a regular basis anyhow).

 

If you see signs of seepage then you can rectify the slave problem well before it becomes serious.  

 

    

 

 

[Lowndes]

RogerC60,

 

To add my 2¢ to what Dirtrider said above.  Maybe closer to 0.01¢ worth.

 

Please, think about it this way: it is WAAAAAY less trouble AND money to replace just the slave cylinder than the slave cylinder AND the CLUTCH.  AMHIK.  (or see pics: https://goo.gl/photos/QEN3xyQVWXW1jraT6).  Hey, go ahead and replace it.

 

I believe said Slave Cylinder can be replaced on most oilheads by removing the rear tire (mostly for ease of access).  Dirtrider will know about that.  Three fillister-head screws on the cylinder base and two banjo bolts should set it free.  Might as well replace the flexible OEM hydraulic lines with Spiegler or Galfer PTFE lines (including the bleeder extension) because DOT4 and TIME eats them, too, and 18 years is past their sell-by date.

 

This weep hole is very similar to in form and function to the water pump weep hole on your '87 Buick (or any other car of that era): It lets you know there is a problem before it gets real.

 

My slave cylinder failed at about  35K.  No weep hole yet.  Had to replace the clutch.  '99 R1100S, 6 speed  (it's similar to your R1150 as I understand it).

 

On opening:

 

 

1/16" hole installed (hard to see, 8 o'clock at back of housing - should have entered closer to bottom and been 1/8" dia, I think):

 

 

 

Outside view, out of focus unfortunately, but you get the idea, black spot almost dead center:

 

[fatbob]

Don’t gamble on the slave cylinder.   Replace it.   I’ll replace my BBY slave at 103K, which will be 50K on the second one.   My original failed at 53K and trash the clutch.    

[RogerC60]

Thank you all for the advice!

[RT1150Ted]

Is there a “better” than other Slave replacement? I bought one from beemer boneyard two years ago and plan on replacing it this winter. My 2004 r1150rt has only 35k miles …fluid looks clean and I changed clutch fluid every 2 yrs…. Bike is stored in dry garage not fully heated.

 

the other slave cylinders I’ve seen have different looking bearing inserts… as well I can’t see on this one if adding bearing grease can get to the bearings?

 

I don’t believe previous owner ever replaced it … no record of it.

 

Thoughts?

 

Thanks

T

[dirtrider]

3 minutes ago, RT1150Ted said:

Is there a “better” than other Slave replacement? I bought one from beemer boneyard two years ago and plan on replacing it this winter. My 2004 r1150rt has only 35k miles …fluid looks clean and I changed clutch fluid every 2 yrs…. Bike is stored in dry garage not fully heated.

 

the other slave cylinders I’ve seen have different looking bearing inserts… as well I can’t see on this one if adding bearing grease can get to the bearings?

 

Thoughts?

 

AfternoonTed

 

That bearing does look pretty tightly sealed so you will probably have to disassemble to get any additional lube into it. 

[RT1150Ted]

Thanks Dirt rider…that was my thought….some posts have implied forcing grease into the opening but looking into it I don’t see open bearings.

 

This might sound a bit out there, but as a cyclist the big rave is ceramic bearings these days.. I wonder if replacing these with ceramic bearings with bearing grease would be added insurance … they seem to last on high end bicycle hubs….

 

T

[dirtrider]

3 minutes ago, RT1150Ted said:

Thanks Dirt rider…that was my thought….some posts have implied forcing grease into the opening but looking into it I don’t see open bearings.

 

This might sound a bit out there, but as a cyclist the big rave is ceramic bearings these days.. I wonder if replacing these with ceramic bearings with bearing grease would be added insurance … they seem to last on high end bicycle hubs….

 

T

Afternoon Ted

 

You might be able to force some grease in through the rear but you probably couldn't tell if any actually got in there unless you took it apart to verify after trying to grease. 

 

I would be hesitant to try any other type of bearing without running prolonged (many miles on multiple motorcycles) durability testing, big difference between a low RPM smooth power input bicycle & a high RPM harsh impulse boxer twin hammering on that bearing. 

[Mike279]

Bearings should not be filled with grease.  The standard is 25 to 35 % of the open area.   Checking a new bearing there should be some grease.  Reusing a older bearing it may need a bit more grease.  Overfilling can cause excessive heat, grease leakage and other issues.  

[MichiganBob]

The slave cylinder on my 02RT failed in the 40K range. It was a total pita to replace the clutch (which was ruined). As the song goes. "I wish I knew what I know now, when I was younger." If I had been on the forum back then, I would have taken heed on the warnings and at the least drilled the weep hole and placed the bike in neutral at stoplights. I would not take the chance on it being okay and would get a replacement. Avoid the nightmare. I did the clutch and slave cylinder replacements myself with a lot of good tutorial help from this forum, especially Dirt Rider. Not sure what it would have cost me at the dealer to replace clutch and slave, probably close to a $1,000 dollars  in labor and parts. The only upside was that I got a very intimate look at all my bike components and how they meshed. But I just have soon been out riding instead. Good luck.

[dirtrider]

40 minutes ago, Mike279 said:

Bearings should not be filled with grease.  The standard is 25 to 35 % of the open area.   Checking a new bearing there should be some grease.  Reusing a older bearing it may need a bit more grease.  Overfilling can cause excessive heat, grease leakage and other issues.  

Morning Mike

 

If the rear of the bearing is open (no seal) then it won't completely fill as there is a seal on the front side so it will air lock then push most on the forced-in grease back out.  (or if too much grease is forced in it will probably unseat the seal)

 

The big question is (IF)  the rear of that bearing is sealed or open to the push rod hole. 

[Mike279]

I usually use a small jewelers screwdriver and slide it between the seal and the inner edge of the bearing. That gives me enough room to insert the needle grease adapter without damaging the seal. It also gives you the option of possibly prying a rubber seal out to look inside.  That would let you verify exactly you are looking at. Rubber seals are easily put back in with finger pressure along the outside edge.  Metal covers are much harder to get out without damage. I usually drill a small hole in those to re grease and then use a dab of silicone sealer over the hole.  A little bit of the right grease goes a long ways.  

[dirtrider]

55 minutes ago, Mike279 said:

I usually use a small jewelers screwdriver and slide it between the seal and the inner edge of the bearing. That gives me enough room to insert the needle grease adapter without damaging the seal. It also gives you the option of possibly prying a rubber seal out to look inside.  That would let you verify exactly you are looking at. Rubber seals are easily put back in with finger pressure along the outside edge.  Metal covers are much harder to get out without damage. I usually drill a small hole in those to re grease and then use a dab of silicone sealer over the hole.  A little bit of the right grease goes a long ways.  

Morning Mike 

 

As long as you have the correct type of grease in your needle grease gun then that should work OK  on the aftermarket slave cylinders with a regular seal but the BMW OEM slave is different so I can't see how that work work on the OEM slave. 

 

The OEM has a small stamped metal area so I'm not sure drilling that would work without fear of getting metal particles into the bearing under it. 

 

 

 

 

[Lowndes]

This is the slave cyl piston (OEM I believe) that failed on my '99 R1100S.  Not a great shot of the rear of the piston (facing 1 o'clock) but I don't believe it is open to the pressure of the DOT4 in the cyl.  I may still have it somewhere.

 

 

 

Below is the front face of the piston with the bearing - the shiney ring is where the push rod seats on the inner race.

 

It doesn't look like a sealed bearing on the front side anyway.  THAT might be part of the problem.  I need to go find it!!

 

[dirtrider]

 

Quote

 

Below is the front face of the piston with the bearing - the shiney ring is where the push rod seats on the inner race.

 

It doesn't look like a sealed bearing on the front side anyway.  THAT might be part of the problem.  I need to go find it!

 

 

 

Morning Lowndes

 

The front of the bearing must be sealed or it would throw grease all over that could migrate along the pushrod into the clutch assembly. The seal is part of the front stamped metal cover.

 

It's the rear of bearing that is of concern to us, if that is open then then conceivably grease could be forced in through the push rod hole into the rear of the bearing. 

 

[RT1150Ted]

Anyone have an opinion between the EnduraLast Oilhead Slave cylinder or the European Slave cylinder from beemer boneyard?

 

looking at the work of replacing and curious if one is better than the other?

 

Thanks

Ted