Article [13] ST1300 - Clutch Slave Cylinder Replacement

[Andrew Shadow]

That is why master-slave hydraulics need to be carefully designed to permit clean fluid to periodically be flushed in to the entire system - which our good friends at Honda did not do.

I have never seen the inside of the slave cylinder, so you have answered my question about the path that the fluid takes. This is what I suspected from looking at the exterior of the slave and from the pictures that people have posted here showing all of the crud inside of them.

I find it surprising that Honda would do this. Hydraulic systems on vehicles are hardly a new technology. They should have known better. It would not have been very difficult to design the slave cylinder so that the hydraulic line connects on the bottom. This would allow fluid to be pumped through it and out the top through the bleed nipple. It would provide for much better flushing of the system. If there is some technical reason preventing this, they could have designed the slave with a hydraulic passage, be it internal or external, that would carry the fluid from the connection point at the top to an entry point at the bottom of the cylinder. This would achieve the same thing.

 

[Sadlsor]

Also, as pointed out above, a substantial portion of the lower part of the hydraulic circuit has a “dead end” around the bleeder nipple in addition to the dead fluid that sits in the slave cylinder itself.

Thanks, @MaxPete I had already realized I must be in constant prayer that I never have need to replace my CSC.
You are less than encouraging.

 

[Igofar]

Why would they want to build a vehicle that requires very little maintenance, and would last a very long time?
That would keep folks from buying new vehicles every couple of years
Rumor has it that Jeep discontinued its Standard Cherokee because nobody every brought them back for service work because they were so reliable, they morphed into the Liberty models that require much more frequent service etc.

 

[MaxPete]

Thanks, @MaxPete I had already realized I must be in constant prayer that I never have need to replace my CSC.
You are less than encouraging.

Hi Sadlsor:

I certainly don’t intend to discourage anyone. Replacing the CSC really isn’t that big a deal.

There are a couple of slightly fiddley steps and the working position is somewhat awkward (on your back, under the bike, looking up into the murky area between the front of the swing arm and the back of the engine) but it isn’t expensive and you are unlikely to run into rusty or broken fasteners.

As I said, follow the article, assemble the tools, and be sure to have your little jar of Vaseline ready to go.

Pete

 

[Igofar]

i certainly don’t intend to discourage anyone. Replacing the CSC really isn’t that big a deal.

There are a couple of slightly fiddley steps and the working position is somewhat awkward (on your back, under the bike, looking up into the murky area between the fron of the swing arm and the back of the engine) but it isn’t expensive and you are unlikely to run into Rusty or broken fasteners.

As I said, follow the article, assemble the tools and be sure to have your little jar of Vaseline ready to go.

Pete

Your starting to sound like a Genuine Honda Service Department with your....."have your little jar of Vaseline ready to go"

 

[Sadlsor]

Huh.
I see what you did there, @Igofar .

 

[MaxPete]

Your starting to sound like a Genuine Honda Service Department with your....."have your little jar of Vaseline ready to go"

hehehhee....yeah, I guess so.

The nearest dealer to me (200+km away in London, ON) which shall remain nameless, is very large and well equipped, but sadly, they have a reputation for screwing over just about everyone who walks through their door.

I have bought two bikes from them - but there not ever be a third.

NOTE: for those who are not in on the joke....the real purpose of the Vaseline is to help stick the three crush washers into the sandwich made up of the clutch hydraulic line (which comes down from the handlebar-mounted master cylinder) and the short line which runs out to the bleeder nipple above the rider's left foot peg.

These two hydraulic fittings are in an assembly (from bottom to top):

1. a copper crush washer is on the bottom next to the slave cylinder body;
2. then the bleeder line fitting;
3. then another crush washer;
4. then the line from the master cylinder;
5. then another crush washer which seals under the head of the banjo bolt;

....and the whole thing is secured with a double banjo bolt. BE SURE to use new crush washers. They are cheap and easy to find - and if you use an old one and it leaks, there will be tears and much use of the "extended vocabulary" and all your hard work will have been for naught and you will have the fun of doing it all over again.

The problem is that the working position is a tad awkward and when I wrote the article, we found that sticking all those fittings and copper crush washers together with Vaseline makes the job much easier. When you bleed the system, the Vaseline just gets washed out the bleeder nipple and if any residue is left, it will just blend-in with the brake fluid/hydraulic oil.

...of course, if you choose to go and have this work done at your friendly local Honda dealer using their ridiculous and expensive: "Step 1 - remove engine from bike" method, you will need the Vaseline for an entirely difference purpose.

Pete

 

[mjc506]

Does the vaseline need a particular moly content? My Honda dealer never uses any...

 

[MaxPete]

Does the vaseline need a particular moly content? My Honda dealer never uses any...

Your Honda dealer almost certainly doesn't care how easily it slips in......

 

[Igofar]

And no reach around or anything

 

[mjc506]

Yup, they don't even offer to polish my helmet or anything!

...I'll stop... hahah

 

[bkra13]

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

Having just completed this job (this thread was invaluable!!!), my guess on this Honda process is that they can't get torque wrenches on the bolts with the engine in the frame. I'm betting they did this to ensure that they can properly torque all the fittings for the csc.

Also - wth was that gasket made of! Getting that off took by FAR the longest of the entire process!! Absolutely baked on and turned to steel (03 ST, 96k miles). half way through I was grumbling that I shouldn't even have started removing it - it came off the csc cleanly but stuck hard to the block. grrr....

 

[Igofar]

So much for your theory about torque wrenches, as my 1/4 inch drive inch pound snap on fits in there easily.
Spray on gasket removal stuff, or even soaking it with WD40 helps soften the gasket up.

 

[bkra13]

So much for your theory about torque wrenches, as my 1/4 inch drive inch pound snap on fits in there easily.
Spray on gasket removal stuff, or even soaking it with WD40 helps soften the gasket up.

Your torque wrench fit even on the Banjo bolt? As for that#$*&(##$ gasket, I sprayed gasket remover, wd40, nothing touched that thing.

 

[Igofar]

Another trick to removing the gasket is what you use.
Wire brushes, razor blades, exacto knives dig into the gasket, braking it apart in many places, making it almost impossible to remove.
I have found the safest and easiest method for
me is to use a 3/4 inch wide wood chisel.
It’s thick so it does not flex and damage the aluminum housing, and the trick is where to start…
I come straight up from the bottom, on the right side of the housing, half of the chisel rests flat against the flat surface of the rear cover, keeping it true, and half pushes up the right side of the gasket, causing it to tilt, without breaking it, so your spray and oil can get behind it to loosen it up.
When using a thick/strong chisel, the gasket usually comes completely off the three pushes etc.
Patience is your friend here.

 

[Igofar]

And yes a torque wrench will work on the banjo fitting if you know how to think outside the box.
For the ST banjo fitting a 15 inch flex head ratcheting wrench, an Allen socket in the user end, then knowing how to calculate the correct formula

 

[Sadlsor]

Daaaaammn!
A Norton manual!
I have the manual, but ain't got no Norton no more. Servicing the bike constantly was more than my lame 20-year-old skills could deal with.
I'm a sad kind of excuse for a klutz mechanic today, but was even more pitiful back 40 years ago.

 

[MaxPete]

All the heartburn over that gasket - and if you stare at it - the danged thing doesn't even seal anything.

The weep-hole runs right past it. The gasket is essentially a little soft spacer for the CSC mounting screws.

Anyhow - glad it worked out for you - and #Igofar is definitely the man for working on STs.

Pete

 

[Andrew Shadow]

does even seal anything.

Presumed to be doesn't.

 

[bkra13]

Another trick to removing the gasket is what you use.
Wire brushes, razor blades, exacto knives dig into the gasket, braking it apart in many places, making it almost impossible to remove.
I have found the safest and easiest method for
me is to use a 3/4 inch wide wood chisel.
It’s thick so it does not flex and damage the aluminum housing, and the trick is where to start…
I come straight up from the bottom, on the right side of the housing, half of the chisel rests flat against the flat surface of the rear cover, keeping it true, and half pushes up the right side of the gasket, causing it to tilt, without breaking it, so your spray and oil can get behind it to loosen it up.
When using a thick/strong chisel, the gasket usually comes completely off the three pushes etc.
Patience is your friend here.

Yeah, that was ultimately what I ended up using but even that had a difficult time with this gasket. I was really hoping not to nick the housing and this time I got lucky. The gasket simply would NOT lift off in any place, there was nothing that popped off. Ah well, it's done, hopefully never again. oops.......