SMC in action!

[Upt' North]

Thanks for the welcome Upt' North, i'm finding the site really helpful, lots of good info.
It just so happens i lived up your end of the world, for over 5 years, back in 2005, a tiny village called Lowick.
If anybody's in the York/selby area there more than welcome to give a shout out.

Small world, the metropolis of Wooler, behind the Tanky.

 

[Jambriwal]

Among the things I didn't think would be an issue on my pristine 2012 ST1300A with 3,600 miles on it when I bought it in the summer of 2020 would be a non-functional SMC the likes of which seemed limited to those bikes with more years and certainly more miles than my new-to-me bike had experienced.

I was quickly schooled by reading the posts by the members of this site. And my first conversation over the White Courtesy Phone and the remote tour of my bike that ensued would reveal that my SMC was indeed frozen and in need of replacement. I performed a full hydraulic service on my bike short of rebuilding my clutch slave cylinder this past July and the improved response of the braking system is quite noticeable... from the saddle.

But in all the numerous threads, and how-to articles, no one to my knowledge has ever actually observed the SMC functioning as intended. Yeah, you can get down on your knees and squeeze the SMC in toward the fork leg to check for free movement, and you can lay beside the bike, spin the rear wheel and test that the rear brake is applied when the SMC is compressed, but I'd never seen it working during actual braking on the road.

I set out to fix that.

I scavenged a RAM® 9mm Angled Bolt Head Adapter Ball Base from my ST1100 and attached it to the bracket that normally holds the reflector on the left fork. Then with a short arm and a RAM to GoPro adapter I mounted my GoPro Hero 8 to the fork leg and set off to collect some data.

Behold! The SMC in action.

For those that will insist on seeing how this was rigged, here's that too.

Enjoy,

Tom

Now we can believe. Thanks

 

[Igofar]

Now if we can just get folks to believe and service their clutch slave cylinders.

 

[jfheath]

Heaven's no John, nobody was implying that you were providing incorrect information.
Your video's and articles are among the very best on the forum!
I've myself explained to many folks that the system, (while pressurized) should only move a couple millimeters as well.

I didn't think that you were, Larry ! I was amused by the notion that popped into my head that people. might think that zero movement is ok simply because just 1mm is good.

I have often recommend pumping the SMC during brake bleeding simply to help get rid of the fluid from the part of the SMC that is out of the normal flow and to 'clean' the SMC bore by allowing the seals to 'wipe' the parts of the bore that are not normally passed. Having seen the excellent video, perhaps that isn't necessary. It won't stop me doing it though !

 

[Igofar]

Since the foot pedal is married to the SMC piston, I have folks do the following:
The PCV nipple needs to be open, once clear fluid is moving, have a helper push the SMC piston all the way in by hand, then while gently Resisting, allowing the pressure to push it back outward, the foot pedal pump(s) it up and extends it outward until it’s fully extended.
The 1st attempt may take 3 strokes of the foot pedal, the he pushes it in fully again, this time it may only take two pumps to fully extend it.
When one pump fully extends the piston, you can then move on to the #4 bleeder etc.

 

[ST Gui]

Well done! I've never seen a video or reference to one showing the SMC in action. Thanks for that!

 

[ksalam]

Well done !

Haaa!! Finger-fumblery... 2012. Will edit to fix. Thanks Gus

Hello I was trying to see if anyone can tell from this picture if my sms is stuck shut

 

[ksalam]

When I was bleeding the breaks the guy said when I was doing the back I could bleed from front brake or back lever but when I did front nothing happened so I used back and fluid flushed from bleeder

 

[Obo]

Hello I was trying to see if anyone can tell from this picture if my sms is stuck shut

Looks like yes as I can't see the hex nut between the rubber boot and the U connector to the fork.

Those are some nasty oily looking lines, forks etc...

 

[Obo]

When I was bleeding the breaks the guy said when I was doing the back I could bleed from front brake or back lever but when I did front nothing happened so I used back and fluid flushed from bleeder

There's a process for bleeding, including tilting the SMC and a bleeder that's under the fairing by the gas tank on the throttle side.

See this article:

Article [13] - ST1300 - Brake Fluid Replacement | ST1300 Articles

Update, 11-2009 This article and related pictures where performed on a 2006 ST1300, non ABS. Fluid replacement for ABS models is exactly the same. This article is for fluid replacement only. If you need to replace brake pads or have additional braking problems, those should be be taken care...

www.st-owners.com

You can also call/email @Igofar on the white courtesy phone.

 

[Sadlsor]

Looks like yes as I can't see the hex nut between the rubber boot and the U connector to the fork.

Those are some nasty oily looking lines, forks etc...

My thoughts exactly.
Would not hurt to clean up and dry that area. Lots of sandy, gritty-looking sediment all over it.

 

[W0QNX]

Among the things I didn't think would be an issue on my pristine 2012 ST1300A with 3,600 miles on it when I bought it in the summer of 2020 would be a non-functional SMC the likes of which seemed limited to those bikes with more years and certainly more miles than my new-to-me bike had experienced.

I was quickly schooled by reading the posts by the members of this site. And my first conversation over the White Courtesy Phone and the remote tour of my bike that ensued would reveal that my SMC was indeed frozen and in need of replacement. I performed a full hydraulic service on my bike short of rebuilding my clutch slave cylinder this past July and the improved response of the braking system is quite noticeable... from the saddle.

But in all the numerous threads, and how-to articles, no one to my knowledge has ever actually observed the SMC functioning as intended. Yeah, you can get down on your knees and squeeze the SMC in toward the fork leg to check for free movement, and you can lay beside the bike, spin the rear wheel and test that the rear brake is applied when the SMC is compressed, but I'd never seen it working during actual braking on the road.

I set out to fix that.

I scavenged a RAM® 9mm Angled Bolt Head Adapter Ball Base from my ST1100 and attached it to the bracket that normally holds the reflector on the left fork. Then with a short arm and a RAM to GoPro adapter I mounted my GoPro Hero 8 to the fork leg and set off to collect some data.

Behold! The SMC in action.

For those that will insist on seeing how this was rigged, here's that too.

Enjoy,

Tom

First time I've seen this video. Nice work.

 

[ksalam]

Looks like yes as I can't see the hex nut between the rubber boot and the U connector to the fork.

Those are some nasty oily looking lines, forks etc...

Yes I'm not seeing we're it's coming from I was going to clean it and see I'm not loosing any fluid that I can tell but it's smells like break fluid. So if this is stuck if I fix this will it let bike change gears properly I wasn't having any problem to my back breaks locked up

 

[ksalam]

Yes I'm not seeing we're it's coming from I was going to clean it and see I'm not loosing any fluid that I can tell but it's smells like break fluid. So if this is stuck if I fix this will it let bike change gears properly I wasn't having any problem to my back breaks locked up

Thanks for all the help

 

[Obo]

Yes I'm not seeing we're it's coming from I was going to clean it and see I'm not loosing any fluid that I can tell but it's smells like break fluid. So if this is stuck if I fix this will it let bike change gears properly I wasn't having any problem to my back breaks locked up

That mess might be fork oil from a bad for seal.

 

[Igofar]

Am I the only one that sees the upper mounting bolt chewed up from pliers or vice grips?
Or the brake caliper rubber grommet sticking out, and appears to be torn and damaged?
Or the damage on the rotor from the alignment of the pads perhaps?
Or the rounded off and damaged non-OEM bleeder?
Or the odd and strange angle of the brake caliper housing?
And.....I seriously hope I'm wrong.....but all that debris on the caliper appears to be aluminum shavings from where the rotor may have been digging into the SMC bracket!
My first thought is someone put the left side wheel spacer in backwards, which moved the caliper over, and then the rotor cuts a path through the SMC bracket.
I have no words.....
Maybe Aniwack can reach out and help him since he's closer than I am

 

[Chris09]

not to sound like Chief Dan George, but usually when you have no words...

 

[Igofar]

That picture scared me .

 

[Igofar]

Can’t see well enough on my phone, but is the the SMC piston retaining C clip on the bottom of the outer brake line?
This may explain all the brake fluid being sprayed everywhere.
I strongly urge the owner of this bike NOT to move or try to Ride this bike until someone who is familiar with the brake system to inspect this bike.

 

[Sadlsor]

I noticed the sandy / gritty stuff, but it didn't occur to me that could be aluminum... but it looks like it could be.
Certainly did not observe it's a non-OEM bleeder, or the angle of the brake caliper. I also assumed it to be fork oil, as that much brake fluid suggests there's not a lot of braking power up front.