slave cylinder

[Rich06FJR1300]

hopefully will get my bike back today. Service manager at CC BMW said it was a slave cylinder he replaced and also a seal for the crown bearing in the final drive. He asked me what oil i was using in the final drive (Redline shockproof) and said it was way too thick...so he put in the bmw synthetic...i've had problems where the oil was spewing out of the vent in the final drive even after i measured the amount to put in (0.75 quarts). So i guess its back to bmw synthetic. I thought the extra viscosity would help lube that bearing that is so known to fail.

Anyway, they still have to test ride it to see that the clutch is not slipping (possible as some fluid may have reached it) but will know later today.

The slave cylinder failed on my way back from the RA rally in shelbyville. Talk about a stressful trip home, it didn't fail altogether but you had to pump the lever several times to get any clutch engagement.

[Les is more]

Jamie and I kept the Redline in the tranny where it seems to smooth things out a bit but went back to the BMW gear oil in the final drive. The Redline does have a tendency to foam up and bubble out the vent and get all over the rear wheel. Not a good thing!

 

Hope the bike checks out and comes home soon .

[Rich06FJR1300]

just got the bill...$1,100.00!!!! minus 75.00 for towing which i can hopefully be reimbursed. They replaced the slave cylinder along with the seal on the final drive, being the brake pads were saturated with oil, they replaced them too. And a headlight....so i counted about 200 bucks for parts and the rest labor? ouch, but didn't see the bill yet.

[RFW]

just got the bill...$1,100.00!!!! minus 75.00 for towing which i can hopefully be reimbursed. They replaced the slave cylinder along with the seal on the final drive, being the brake pads were saturated with oil, they replaced them too. And a headlight....so i counted about 200 bucks for parts and the rest labor? ouch, but didn't see the bill yet.

 

Now I know why I do all my work (both major, and minor like your work) myself! By the way, there is nothing magic about BMW oil regarding how "way too thick" you other oil was. Viscosity is viscosity! If BMW requires SAE80, or 80w90 or whatever, then ANY suitable GL-series oil with that viscosity will not be "way too thick". I'm assuming you didn't ignore the required viscosity and put something of higher viscosity in there. It is also not possible for a higher viscosity oil to blow out the rear angle drive seal. Someone is giving you a snow job.

 

Bob.

[Stan Walker]

i've had problems where the oil was spewing out of the vent in the final drive even after i measured the amount to put in (0.75 quarts).

 

If you somehow were able to actually put 0.75 quarts of oil in the final drive you probably would have some interesting problems. The correct amount is 0.23 litre (0.24 quarts).

 

Stan

[Stan Walker]

And a headlight....

 

Headlight bulb (fairly cheap) or headlight assembly (very expensive)?

[Rich06FJR1300]

oops...got me on the fluid...it was 1/4 qt. Doh! Headlight bulb only. But like Les said i just had a problem with that oil foaming and it was constantly coming out of the vent. So from now i'll just use the bmw oil. That is until I sell this damn thing before i go broke!

[ShovelStrokeEd]

Am I missing something here?

On an 1150RT you shouldn't have to pull the swing arm to change the slave cylinder.

Where is the labor cost?

Headlight bulb takes about 10 minutes, Oil seal for the rear drive can be done on the bike, as stated earlier, slace cylinder is 3 bolts once the rear wheel is off and the swing arm propped up.

Sounds to me like they did a whole bunch of unnecessary work, or at least billed for it.

[Stan Walker]

slace cylinder is 3 bolts once the rear wheel is off and the swing arm propped up.

 

The shop manual, and probably the book rates reflects this, call for raising the rear sub-frame about 1/2 inch. This adds considerable work to your list to replace the slave unit.

 

At $80-90 dollars an hour it adds up really fast!!! I wish I got paid that much at my work.

 

The easy answer for me is to do all my own work. That doesn't work for some people. With 4 BMW's in my stable I couldn't afford the shop to do it all my servicing. None of my bikes has seen the inside of a BMW repair facility in many years, not even for tires.

 

Stan

[Paul Mihalka]

At $80-90 dollars an hour it adds up really fast!!! I wish I got paid that much at my work.

Stan

The technician working on the bike does not get that either...

[Stan Walker]

The technician working on the bike does not get that either

 

 

I know that!!! I've even seen what companies I've worked for charge for my time...... <sigh>

 

Stan

[Jezzer]

Am I missing something here?

On an 1150RT you shouldn't have to pull the swing arm to change the slave cylinder.

 

Ed, this is a case of BMW screwing up twice on the same component (or maybe it was part of the plan?). They made a poor design of slave cylinder with a graphite like seal that fails, then stuck the thing where you have to pull the bike apart to get to it.

 

I had mine changed earlier this year (search my posts - there aren't many). Re: your earlier comment about 3 references not indicating a major design fault is not necessarily correct. Peole who post on this site do not represent teh majority of bike owners. The mechanic who repaired my bike is an ex BMW guy now working for himself. He said this was one of his more common repair jobs, and showed me a number of failed slave cylinders around his workshop - all covered in grey slime. As soon as he saw the grey coloured fluid at the master cylinder he advised me not to rise it as unpredictable instant failure of teh salve cylinder was a possibility. The dealer actually spotted it when I went for a service earler and told me knew I needed a new cylinder - said he'd "tested" it and was certain, but wouldn't tell me how - which is why I went elsewhere. I now know he saw the grey liquid at the top! I am sure it's a very common problem.

[ShovelStrokeEd]

Jezzer,

No offense but there are some 10,000 members on this site and probalby 6,000 of them pretty active. That is more than enough to form a representative sample and the problem is not that large. I agree on the BMW screw up.

 

I also distinctly remember Jamie and maybe Ken H., both quite knowledgable about things BMW, telling me that the slave cyclinder could be changed without taking apart the bike. As a matter of fact, when the transmission blew on my GS ADventure the dealer changed the slave cylinder without pulling the swing arm so I know it can be done. I'm pretty sure all the transmission cases are the same on the 6 speed bikes so they should be able to do it on an RT.

[Ken H.]

The slave cylinder on the 1150 series most certainly can be changed with the swing arm firmly in place. I've done several. It's a bit tricky to get to one of the three allen-head bolts, but with a long ball-end allen key it can be done. Beats pulling the swing arm that's for sure!

 

To give the dealer a little bit of credit, the factory manual probably says to pull the swing arm like with the 1100 series. But someone doing more than 'reading the directions' should easily be able to see how to do it without doing so. But then again maybe I'm expecting too much... Sigh...

[Rich06FJR1300]

Now i got more info. They replaced the master cylinder as well (termed the handle unit) and that constituted of about 330 bucks. So that is why there is so much more on this. Its kind of suspicious on there part why they did this when it couldn't be cleaned out but probably to be on the safe side, they replaced the entire circuit. So i'm still pissed and sent the bill off to BMW NA.

[RFW]

Now i got more info. They replaced the master cylinder as well (termed the handle unit) and that constituted of about 330 bucks. So that is why there is so much more on this. Its kind of suspicious on there part why they did this when it couldn't be cleaned out but probably to be on the safe side, they replaced the entire circuit. So i'm still pissed and sent the bill off to BMW NA.

 

This sounds bloody suspicious. Replacing BOTH the master and the slave cylinders?? The chances that both were defective are very slim indeed.

 

Bob.

[Rich06FJR1300]

I'm just guessing but maybe they're thinking is that the fluid was contaminated and that if I didn't replace the master cylinder now, that would probably fail next. But you're right, it is kind of strange.

[RFW]

I'm just guessing but maybe they're thinking is that the fluid was contaminated and that if I didn't replace the master cylinder now, that would probably fail next. But you're right, it is kind of strange.

 

Funny, isn't it, how service departments (car AND bike) are so cavalier in their replacement of expensive parts "just in case". They seem completely unconcerned that the part they are replacing that has only a minor likelihood of really being a problem, is really expensive.

 

I'll bet someone, somewhere, has run up against something like... "We heard a faint noise, so "just to be safe" we replaced the transmission". (of course, the noise will likely be there still!).

 

Sarcasm will get the best of me yet!

 

Bob.

[RickC]

They made a poor design of slave cylinder with a graphite like seal that fails,

 

Do you know if there has been any improvement with the design or the material used dealing with the seal failing? I am new and seeking out information.

[Rich06FJR1300]

have no idea, all i know is its one issue after another on the RT. Do i really have to put up with this crap with other manufacturers?

[RFW]

hey made a poor design of slave cylinder with a graphite like seal that fails,

 

What is this "graphite seal" thing? Every slave cylinder I have ever seen and rebuilt (and there were many, albeit in cars, not bikes) used a standard butyl rubber piston seal. What is BMW doing with graphite here? Sounds more like a waterpump seal than a slave cylinder seal!

 

Bob.

[Ken H.]

What is this "graphite seal" thing? Every slave cylinder I have ever seen and rebuilt (and there were many, albeit in cars, not bikes) used a standard butyl rubber piston seal.

I'm not sure where that idea is coming from. Every one I've had apart looked like a plain old butyl rubber seal to me. But then I'm no compound expert either.

[Ken H.]

I hypothesis that the root cause of failure of the slave cylinder has more to do with the design of the clutch rod to diaphragm spring contact point, than the cylinder itself.

 

The rod is suppose to only spin when the clutch is pulled and the rod is pushing the diaphragm spring. The small bearing in the rear clutch cylinder should be easily up to the duty cycle of that.

 

But if you ever have the clutch on a R bike apart, and see the rod end that contacts the diaphragm, they all show signs of wear. Some to the point where it looks like the rod is wearing through the center hole in the diaphragm spring. There is very little lube (and it drys up) on that point from the factory. Theoretically the rod and the diaphragm spring should rotate at the same rate (the rod rotating in the bearing at the rear) when the clutch is pulled. But yet they all show signs of wear indicating to me that they are not. It is easy to envision a condition developing, especially on a self-adjusting, self-advancing hydraulic clutch, where the friction between the diaphragm spring and the rod becomes such that the clutch rod spins all the time. And the bearing in the slave cylinder is clearly not up to that. It overheats and in turn takes out the seal. Remember too that as the clutch plate wears the clearance between the diaphragm spring and the clutch rod decreases, exasperating the situation.

 

When doing a slave cylinder replacement the prudent tech IMHO will pull out the clutch rod at the same time and at the very lease lube the tip to possibly help, but certainly not hurt, the future reliability of the design. Which unfortunately we are stuck with.

 

At least that's my theory today!

[steve.foote]

When doing a slave cylinder replacement the prudent tech IMHO will pull out the clutch rod at the same time and at the very lease lube the tip to possibly help, but certainly not hurt, the future reliability of the design.

 

And, considering that the clutch rod is only about $15, why not just replace it at the same time?

[Cali Kid]

The rod is suppose to only spin when the clutch is pulled ...

 

Where the hell did you get that idea ken?

I'm not being sarcastic, cause I'm sure you've seen the inside of a clutch slave cylinder. There is a spring that applies constant pressure to the bearing/rod/diaphram. The rod would flop all about if it didn't have pressure. The rod will always spin with the cluch disengaged. It wears the diaphram when it doesn't, as you stated.

The reason it does wear is because the contact point at the diaphram is insufficient to provide the necessary friction to rotate the bearing in the slave at the same speed. So the rod doesn't keep up with the clutch and it wears. But the bearing is always under pressure and spinning. There would be no way to avoid it unless there were complete disengagement of the rod from the clutch, which there isn't.

Bad design in my opinion, which could be solved with a bit larger bearing and a rod that keys into the diaphram.

 

[Jezzer]

What is this "graphite seal" thing? Every slave cylinder I have ever seen and rebuilt (and there were many, albeit in cars, not bikes) used a standard butyl rubber piston seal.

I'm not sure where that idea is coming from. Every one I've had apart looked like a plain old butyl rubber seal to me. But then I'm no compound expert either.

 

Allow me to explain the source of the comment. Firstly I have not seen a disassembled slave cylinder, but I have seen several three failed units sitting on the bench, and I've seen the colour of the clutch fluid in a system with a failed cylinder. The fluid is grey in colour, not clear or green - i.e. dirty. The failed cylinders wre covered all over in a greyish, graphite looking(!) paste which is most obviously a mixture of clutch fluid and something from INSIDE the unit. This is supported by the fact that the grey liquid is visible in the master reservoir at the handlebars. The mechanic claimed the seal assembly was the time that was failing, and he described it as a graphite like component. I have seen butyl rubber, and I agree it is hard to imagine a breakdown product that looks like what I have seen as a paste. He did say that after replacing units he has not seen any further failures. Maybe there is a problem with just one batch of slave cylinders sourced from one manufacturer, or made at one perticular time, and sold predominately in one market area (Europe?) with some ending up in the USA... I think it is the type of problem that a good sub-supplier would modify immediately once aware of the root cause of failure if it did not significantly affect the price - and changing a seal would fit this criterion. Not sure BMW engineers think this way - but the slave cylinder manufacturer might.

 

I can't be certain, but the issue of the push rod lubrication sounds like it might be a totally separate problem.