Article [13] ST1300 - Clutch Slave Cylinder Replacement

[edward]

Another big thankyou from me. Just changed the slave cylinder, no apparent fluid loss but lost all resistance at lever when hot. Did the usual bleed etc and lever felt normal once cooled off. Problem returned when engine hot. Only when I removed the unit could I see the problem. The cylinder was a mess of encrusted old fluid from I suspect a very slight leak, this had blocked the drain hole and so there was no signs of a leak. I don't do many miles and have changed the fluid every two years. I suspect it never leaked enough between changes to cause a level problem but eventually gave up. I have no idea why the workshop manual requires engine removal, that in its self is enough to put people off doing it themselves. Once again thanks for taking the time to take great pictures and share your knowledge, Ed

 

[MaxPete]

Thanks for the kind words Ed - glad you were able to get the job done.

I completely agree with your assessment of the “Honda-approved” method - totally silly and unnecessarily expensive, complex, risky and ill advised. I cannot imagine why a fine engineering firm like Honda would make such a stupid recommendation.
Pete

 

[edward]

Pete, me neither, considering the expense of the genuine manual I would have expected more accurate information, I would like to think the engineers left just enough room to remove the cylinder instead of it just being good fortune that it can be removed in situe. Guess we will never know.
Ed

 

[JackinFL]

My clutch just started acting like you describe and when I looked on here for possible causes I found this article. Thanks @MaxPete for the great write up and letting me believe I can do this without much hassle!
I'm starting to gather up the parts to do this now so hopefully I'll not be off the road for too long.

 

[MaxPete]

Cool - have at it.

 

[accordvtec77]

Hey guys...so it seems like it'll be my turn soon, to tackle this job. And I apologize in advance if this has been mentioned, I tried as best as I could to read through the entire thread. Has anyone attempted to remove the oil cooler ITSELF in an attempt to make more room? I've got a LOT of maintenance I need to do on my bike, coolant included And seeing as the oil filter has to come off anyways...maybe the cooler itself might give me more space. So has anyone tried this?

 

[Andrew Shadow]

Has anyone attempted to remove the oil cooler ITSELF in an attempt to make more room?

A word of caution if you decide to go this route.
Several years ago several of us attempted to find a P/N for the O-ring that goes between the oil cooler and the engine block. We have never been able to find one. I have not read that anyone has found it since then. The parts lists do not even state if a new oil cooler comes with the O-ring or not.
If you remove the oil cooler, be careful not to damage the O-ring as you will have to re-use it.

 

[Fred Primmer]

I did mine on the side stand with only removing shifter linkage and oil filter. I also changed the coolant and engine oil at the same time so I had some fairings off as well. I wouldn't remove the oiler cooler. I didn't find that the three bolts on the CSC were difficult to access with a 1/4 in drive ratchet. I found the most difficult part was getting the banjo fitting bolt started in the new CSC. My bleed line banjo fitting was cocked at an angle and wouldn't let the bolt align correctly. I had to remove the bolt on the bleed line bracket on the left side of the bike by the bleeder valve. With the bleed line completely free the banjo fitting bolt installed easily. I then reattached the bracket by the bleeder valve. Be very careful not to cross thread the banjo fitting bolt into the aluminium casting of your nice new CSC!

 

[MaxPete]

I wrote the article on the clutch slave cylinder replacement and I found no need to remove the oil cooler. Quite a few (20?, 30? or more) other folks have also done this task and nobody has mentioned removing the oil cooler - so it seems unnecessary and as Andrew points out, risky.

 

[Igofar]

Hey guys...so it seems like it'll be my turn soon, to tackle this job. And I apologize in advance if this has been mentioned, I tried as best as I could to read through the entire thread. Has anyone attempted to remove the oil cooler ITSELF in an attempt to make more room? I've got a LOT of maintenance I need to do on my bike, coolant included And seeing as the oil filter has to come off anyways...maybe the cooler itself might give me more space. So has anyone tried this?

No need to remove the oil cooler housing.
You have plenty of room with a simple K&L center jack lifting the bike up just enough to deploy & raise the center stand.
With a few special hand tools you can remove and replace the CSC easily.
Standing by the white courtesy phone if needed.

 

[accordvtec77]

A word of caution if you decide to go this route.
Several years ago several of us attempted to find a P/N for the O-ring that goes between the oil cooler and the engine block. We have never been able to find one. I have not read that anyone has found it since then. The parts lists do not even state if a new oil cooler comes with the O-ring or not.
If you remove the oil cooler, be careful not to damage the O-ring as you will have to re-use it.

Yeah...I came to that same realization about that o-ring when I took another good look at the parts catalog. Well alrighty then...I will scratch that idea. But thanks for the advice everyone! It's appreciated!

 

[JackinFL]

Thanks to MaxPete and Igofar I was able to finally do this!
Igofar gave me detailed instructions over the phone and the pics that MaxPete really helped me understand what Igofar was talking about.
One tip...
Pay attention to the reservoir between the bleed nipple and the vacuum pump. If it happens to fall on its side and you don't notice, you will very quickly be pumping brake fluid into the pump and all over your hands.

 

[sturge]

Just did this on my 2005, 103000 mile machine. Thanks everyone for the write-up, it is a straightforward job just on the side stand, albeit a little fiddly at times.
It would have been much easier if I hadn't had to rebuild my vacuum bleeder that had seized since last used last year (just a strip, clean and grease with silicone grease needed). And if I hadn't left my 1/4 drive socket set on my desk at work. Gave me an excuse to buy a tiny 1/4 ratchet from Amazon, which will come in useful I'm sure. Only the bolt between the CSC and the oil filter really needed 1/4, I did the others with my 3/8 set.

Another satisfying job done on the old girl. Next to sort out some small leaks on the half moons of the rocker cover gaskets. About due for a valve check anyway.

 

[Cajun T-roy]

I to had to replace my clutch slave cylinder. Check out my pictures. https://www.st-owners.com/forums/threads/why-you-should-flush-clutch-fluid-once-a-year.180357/

 

[Andrew Shadow]

So continued flushing will not necessarily get rid of potential sludge in the CSC. Only way then is to remove and clean or remove and replace?

I don't have the answer to that question. Because the fluid inlet and outlet ports are both in the upper part of the casting, several people on this site have speculated that the fluid is taking a short-circuited route between the two. While this won't affect the ability to bleed any air out, it is assumed that this fluid route prevents the ability to efficiently flush out any sludge from the bottom half of fluid cavity, and is mostly flushing the upper part only. These seems to be supported by the fact that most people who have taken it apart have always found it to be quite messy and full of sludge in there.

With enough bleeding, the fluid will eventually all get replaced. If there is a direct route between the inlet and the outlet ports, whether or not there is enough fluid volume going through the bottom part of the cylinder to flush out accumulated sludge is the question.

I haven't taken one apart myself so I can't say whether there is a direct route between the two ports or not. It is possible that there is an internal passage that routes the incoming fluid to the bottom before it enters the cylinder, which would allow for a more thorough flush. Nor have I read on here that anyone has reported what the actual internal fluid path is between the inlet and the bleeder nipple.

Maybe someone who has an old one hanging around can open it up and have a good look and let us all know what the fluid path is. If the fluid path does take a direct route between the inlet and outlet ports as speculated, this would be a good incentive to decrease the interval between flushes to prevent sludge build up as much as is reasonably possible.

 

[mjc506]

The line from the master cylinder to the CSC and the line from the CSC to the bleed port are both fitted to the top of the CSC with a double banjo bolt. Fluid can flow from the master and out of the bleed port without passing through the CSC.

Internally, fluid flows straight from the banjo on top of the CSC straight into the piston bore. Nothing clever in there unfortunately!

'Best' you can do without removal is probably squeezing the clutch lever (extending the CSC piston slightly) then opening the bleed port (the piston returning pushes some fluid out). I can't imagine much fluid moves though!

 

[Esti1300]

'Best' you can do without removal is probably squeezing the clutch lever (extending the CSC piston slightly) then opening the bleed port (the piston returning pushes some fluid out). I can't imagine much fluid moves though!

I did just that hoping the pressure build up and release might move some of the sludge out the bleed port but I just got more clean fluid being pushed out faster . What can I tell ya, guess I will keep a close eye on it and if it means flushing twice a season, so be it.

 

[Sadlsor]

Has @Igofar weighed in yet?
Lazy me -- I don't have time to reread all 13 pages...

 

[Igofar]

Several times....try to keep up
I've replaced a couple dozen units in the past few months, and have a slightly different method of doing them.
I've got it down to about an hour.
Since this is an Article, and a very good one, I didn't want to take away from the gist of it.

 

[Sadlsor]

Several times....try to keep up

Try to keep up?!
I wish!
Just got back after being out for FIVE months, and have 9299 posts I haven't read.
Won't catch up for another 7 years!
Maybe I'll get to read the 13 pages in this thread, in 2 or 3 months...