Article [13] ST1300 - Brake Maintenance - Photos of dismantled SMC

[jfheath]

The point was - we knew that it was tiny. But my 0.012 E string went through the hole in my last SMC (30,000 miles), but the exact same string did not go through my current (37,000) mile hole.
Larry said it was a light electric guitar string - really tiny - that he used.
I really can't say whether there was a hole there or whether it was blocked. It wasn't blocked by crud - nothing came out, but there is definitely a 0.012 hole there now !!

[edit]

And did it make a difference to being able to push in the two rear outer pistons by hand ? Yes. Marginally. It is now possible using only two thumb pressure. Before it needed the assistance of a gently twist/pry an oval shaped 'tool'. (A screwdriver handle). This applies pressure to all sides of the piston equally. But I did notice the the front centre piston was difficult to push in by hand too - so that suggest (maybe) an issue with the rear master cylinder compensation port. That can wait for a while. Everything else is very clean - including behind the front caliper pistons.​

 

[GitSum]

Well, tonight after reading this and a number of other posts on the SMC, I decided to take mine apart on my 'new to me' 2012 that I have ridden for less than 10 miles. I was shocked to see the condition it was in. (This bike was really clean and well maintained - only 18k miles on it and I have really gone through it)



Ended up ordering a new one from Web Bike World - $112 including shipping. Their website indicated they had 3 left and I did confirm the part number for my 2012 - (they make it clear no cancellation/refund)

HONDA OEM Motorcycle parts : Bracket Sub-Assy., L. Fr [06454MCSR02]

Product Description: HONDA OEM Motorcycle parts Bracket Sub-Assy., L. Fr [06454MCSR02] : Fits:HONDA ST1300PA AC 17 LEFT FRONT BRAKE CALIPER : HONDA ST1300PA AC ... - Webike

japan.webike.net

Thanks for the info and all the work you put into this

 

[Igofar]

Well, tonight after reading this and a number of other posts on the SMC, I decided to take mine apart on my 'new to me' 2012 that I have ridden for less than 10 miles. I was shocked to see the condition it was in. (This bike was really clean and well maintained - only 18k miles on it and I have really gone through it)



Ended up ordering a new one from Web Bike World - $112 including shipping. Their website indicated they had 3 left and I did confirm the part number for my 2012 - (they make it clear no cancellation/refund)

HONDA OEM Motorcycle parts : Bracket Sub-Assy., L. Fr [06454MCSR02]

Product Description: HONDA OEM Motorcycle parts Bracket Sub-Assy., L. Fr [06454MCSR02] : Fits:HONDA ST1300PA AC 17 LEFT FRONT BRAKE CALIPER : HONDA ST1300PA AC ... - Webike

japan.webike.net

Thanks for the info and all the work you put into this

You'll need part number #12 (grommet) also, and 4 new crush washers.
makes me wonder what condition your clutch slave cylinder is in?
If you want to spend a few minutes on the white courtesy phone, give me a call, and I'll walk you through some inspections, and stuff to check, that you probably had/have no idea that its wrong/damage/needs to be replaced

 

[Sadlsor]

One thing we learn around here (if not already known) is motorbikes need to be ridden, to preserve their youth.

Museum pieces and garage queens, counter-intuitively, die an early death due to neglect. Like us, they need regular exercise to stay in good shape. Now shut up and pass the jelly doughnuts.

 

[W0QNX]

the set I bought is not there now but Amazzzzz has small bits cheap.

https://www.amazon.com/dp/B09XXFWGXM/ref=sspa_dk_detail_1?psc=1&pd_rd_i=B09XXFWGXM&pd_rd_w=AJH2f&content-id=amzn1.sym.386c274b-4bfe-4421-9052-a1a56db557ab&pf_rd_p=386c274b-4bfe-4421-9052-a1a56db557ab&pf_rd_r=4KQ7XAC3AED2YZSKEV96&pd_rd_wg=P3rD9&pd_rd_r=7a245632-19c8-4114-a40a-f81796db7b3a&s=industrial&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWxfdGhlbWF0aWM

 

[Andrew Shadow]

For as well as the brakes on the ST1300 work when they are working properly, and I do find them to have a very efficient braking system, I do think that Honda really screwed up on this SMC design. There are hardly ever any troubles with the SMC on the ST1100. They had already learned the design lessons with it, why did they feel the need to redesign and improve it?

 

[GitSum]

I am not seeing how to get the top white screen off the cartridge?

And to confirm, when it goes back together, the larger hole goes over the smaller hole in the casting?




edited to add - I was able to get a strand of copper wire (.009") up through the small hole using some forceps to keep it from bending over

 

[jfheath]

It doesn't matter - although it would be logical. But the tiny port emerges into the bottom of the inlet port - not as a hole, but as a hollow with a hole in the middle of it. It is countersunk.
The blue spars that hold the spring and non return valve in place are narrower than the width of that hollow. So whichever way you put it in, the fluid emerging from a 0.009 inch hole is going to find a way through.

Getting the white screen off - I use a couple of pins. There is a bit of a recess between the white nylon body and the ring that holds the gauze. With a pin you can poke into the side, and lift it a bit. With two pins, you can stop one side going back down while to do the same on the opposite side.

When replacing the assembled cartridge, the blue bit goes in first - so you cannot see it.

I've modified the image to show a representation of the recess.

 

[GitSum]

It doesn't matter - although it would be logical. But the tiny port emerges into the bottom of the inlet port - not as a hole, but as a hollow with a hole in the middle of it. It is countersunk.
The blue spars that hold the spring and non return valve in place are narrower than the width of that hollow. So whichever way you put it in, the fluid emerging from a 0.009 inch hole is going to find a way through.

Getting the white screen off - I use a couple of pins. There is a bit of a recess between the white nylon body and the ring that holds the gauze. Wiht a pin you can poke into the side, and lift it a bit. With two pins, you can stop one side going back down while to do the same ont he opposite side.

When replacing the assembled cartridge, the blue bit goes in first - so you cannot see it.

I've modified the image to show a representation of the recess.

Thanks, I am pretty sure that is how the cartridge was placed when I took it apart, but the photo didn't come out... Removing the white screen took more effort than I expected, definitely need two things to get the screen part straight up and out.

I think I am going to clean everything up and just run with it - making sure I have a 8mm 'emergency wrench' on hand for a bleed screw, if needed.

This bike exhibited no actual symptoms, the rear brake pads were worn pretty uniformly and everything else appears to be in good condition.
I used some 3000 grit Trizact wet sandpaper, it has a foam backing, to gently clean everything up and I will have the new SMC (at a decent price) to fall back on if needed

 

[jfheath]

I would do it the other way round. Fit the new one, use the old one as a backup. SMCs do not fail by themselves, they need help - like not having fluid changed; thinking that putting grease behind the boot and then failing to refit it correctly; some previous owner messing with it; bike falling over and knocking the bore out of shape. Your old one failed badly - otherwise it wouldn't look like that.

But now you know what it looks like when it is neglected, you will not let it. All it needs is a good flush of new fluid from a brand new sealed container every year or 18 months, using the correct procedure.

If you ever lift that boot on the SMC, make absolutely certain that it is placed correctly and that it seals. There's another of my posts in the article section about that. I reckon that your seal has not been fitted properly. Ask if you don't know. Link

Mine have never looked like that, nor have they ever failed. The photos at the start of this thread were reporting on a friend's SMC that did fail, so he gave me it to cut open. It was a learning process. My recent post was a result of needing to remove the left caliper to investigate why the caliper didn't seem to be sliding properly. So I took the opportunity to take a look at what mine was like after 37000 miles, see what, if anything, was going on. I was curious !

 

[GitSum]

I will keep in mind, but part of me wants to find out why this can't be just a simple fix? None of the parts actually appear to be damaged or corroded enough to actually affect their operation, but there was definitely some water intrusion. The rust marks appear to have been from the little metal washer that sits on top of the spring. For the most part, they washed right off.

I agree that making sure the rubber boot is full of grease should be a regular/annual maintenance item

 

[OhioDeere]

Some explanation. DOT 4 is very Hygroscopic vs DOT 3.. "absorbs more water".
DOT 3 vs DOT 4

 

[GitSum]

I am well aware of that, but this is more of a case of 'water intrusion' along with dirt and other 'road grime'. I took apart all (3) calipers for inspection and cleaning and they all looked good - no signs of corrosion on any of the pistons, or fluid contamination behind them.

I think keeping that rubber boot filled with grease would go a long way in preventing this from happening (along with routine brake fluid flush. Not the best design by Honda, but it is what it is.

 

[STRider]

Thanks, I am pretty sure that is how the cartridge was placed when I took it apart, but the photo didn't come out... Removing the white screen took more effort than I expected, definitely need two things to get the screen part straight up and out.

I think I am going to clean everything up and just run with it - making sure I have a 8mm 'emergency wrench' on hand for a bleed screw, if needed.

This bike exhibited no actual symptoms, the rear brake pads were worn pretty uniformly and everything else appears to be in good condition.
I used some 3000 grit Trizact wet sandpaper, it has a foam backing, to gently clean everything up and I will have the new SMC (at a decent price) to fall back on if needed

Since I had a photo of the part in question in the state in question...

Here's the cartridge in the SMC before I removed it. Nuf said.

 

[GitSum]

Just for info, the SMC I ordered from WebBikeWorld in Japan was delivered today. I ordered it on March 17th, so just about 10 days total, which I thought was pretty reasonable, especially at this price point. Well packaged, and factory sealed.

I thought it would take a lot longer (up to a month), so I went ahead and changed it out.

 

[eyrepb]

Hello all. In the middle of brake bleed after rebuilding about the entire brake system. I installed a SMC service kit. I've got a leak at the SMC "Lozenge" part when pumping rear pedal. I could not find a good parts diagram, ,torque spec for same. Did I forget a seal? I also did the thing I wasn't supposed to do (disassemble the plunger, without pre-measure.). Does anyone know the precise measurement, as I was unable to find it. Trying to salvage my $200 mistake.
TYIA

 

[jfheath]

Previous posts above yours from @STRider - there's a rubber 'O' ring. Did you miss that ? Is that the lozenge that you mean ?

What year bike. I have a vernier caliper measurement for a brand new 2008 and later SMC. But 2007 and earlier are a different design - I do not know whether the measurement is different.

 

[eyrepb]

I missed the above pic. Bike is A6. Thank you!
This helps!! Installed orphan o-ring. still leaks. With that plus unknown dimension, Gonna order a new SMC.
Thank you

 

[jfheath]

Good plan. I'll remove the link to the measurement photo in case it is used out of context. It's still available elsewhere on these pages. Buying a new SMC for a 19 year old bike can never be the wrong thing to do.

Do not be tempted to check behind the rubber boot of your new one. It is extremely difficult to be certain that it has been refitted properly.

 

[eyrepb]

I just received my new SMC. Waiting on more crush washers. I intend to hang the brake components loosely, dry, and see if @Igofar will take a call to advise next steps. In case anyone has done "what they shouldn't have done" and wants to spitball SMC reassembly here's pics of the new SMC: