Pre-Purchase Inspections Are IMPORTANT!!

[Igofar]

Don't be surprised if your victory is short lived.
You should spend some time reading Mr. Heaths write ups on avoiding the pitfalls etc.
Several things wrong with what you did, and a couple quick explanations of why it was probably not a long term fix.
1. The factory service manual warns you not to take your SMC apart, the reason being, is that it is measured and set at the factory to work correctly.
The small return port hole rests between the two seals, and its possible to get the length wrong and block the flow of fluid.
2. The small screen cartridge on the back side of the SMC inlet has an O-ring (not supported by Honda) and a nylon mesh type filter system that is easily torn or damaged, and between the
screens of this cartridge, there is a very small hole, that clogs and blocks the return port flow etc.
3. Unless you removed this cartridge, the HP seal, O-ring, and cleaned it with an ultrasonic cleaner (which still only works about 50% of the time) you more than likely simply moved the dirt inside
the screen cartridge around, and as soon as it settles, your problem will return again.
There have been other members who have tried to clean and rebuild these units only to have the SMC fail again a short time later.
If the SMC shows signs of failure, its best to replace it with a complete, measured, correctly put together assembly, rather than hope you got it back together correctly etc.

 

[Sadlsor]

Hard. Normally you need tools to remove it.

For sure.
If it was assembled correctly, your fingernails just won't do.
Unless you're Chuck Norris, which you aren't.

 

[Weaselinsuit]

I guess that works, if you don't have a fiddle or a guitar strapped to the back...

You gotta have a fiddle in the band…..

 

[SupraSabre]

Well, with all the luck people have not had at rebuilding a SMC, I guess @Byron and I did okay!

Rebuilding the SMC, and other rear components

That was almost 9 years back and over 70,000 miles ago.

And with regular maintenance, it's running great!

 

[jfheath]

The other thing about that nylon cartridge is that it has a one way valve. It is possible to put it back the wrong way round. This will probably affect the braking performance a little bit. Don't ask me which way it fits. I could work it out, but I might be wrong. Anyway I wrote it all down so that when my memory fails, everyone else will have read it, and they can tell me.

There are 3 of them in this filtered article search

ST1300 Articles

www.st-owners.com

Well worth considering is the boot replacement - a possible cause of failure.

If you ever have your SMC apart then practice this. Now I know what it feels like when the boot seals properly, I reckon that there will be many boots that have not - based entirely on a statistically unrepresentative sample of one. But I tried many ways of doing it and failed each time. Until I finally got it right.

 

[SMSW]

How hard would it be to pull the rear caliper off the bike?

Don't you have to pull the rear wheel? It's been a long time since I looked at an ST (sold mine). Quite a job on the side of the road. No doubt our bike whisperer could do it with the tools he carries on his belt, but the rest of us?

 

[Larry Fine]

Hard. Normally you need tools to remove it.

I meant with tools.

 

[MattSTlouis]

Don't be surprised if your victory is short lived.
You should spend some time reading Mr. Heaths write ups on avoiding the pitfalls etc.
Several things wrong with what you did, and a couple quick explanations of why it was probably not a long term fix.
1. The factory service manual warns you not to take your SMC apart, the reason being, is that it is measured and set at the factory to work correctly.
The small return port hole rests between the two seals, and its possible to get the length wrong and block the flow of fluid.
2. The small screen cartridge on the back side of the SMC inlet has an O-ring (not supported by Honda) and a nylon mesh type filter system that is easily torn or damaged, and between the
screens of this cartridge, there is a very small hole, that clogs and blocks the return port flow etc.
3. Unless you removed this cartridge, the HP seal, O-ring, and cleaned it with an ultrasonic cleaner (which still only works about 50% of the time) you more than likely simply moved the dirt inside
the screen cartridge around, and as soon as it settles, your problem will return again.
There have been other members who have tried to clean and rebuild these units only to have the SMC fail again a short time later.
If the SMC shows signs of failure, its best to replace it with a complete, measured, correctly put together assembly, rather than hope you got it back together correctly etc.

Fine then, new SMC installed and another ordered. My 2004 Harley is really looking good and cheap to own right now.

 

[Igofar]

Now remove those two 8 mm bolts on the inlet port, and used compressed air to blow the cartridge out and see what it looks like.

 

[970mike]

Fine then, new SMC installed and another ordered. My 2004 Harley is really looking good and cheap to own right now.

You might want to tighten those bolts on the brake caliper!

 

[MattSTlouis]

Now remove those two 8 mm bolts on the inlet port, and used compressed air to blow the cartridge out and see what it looks like.

It looked fine when I had it out 2 days ago

 

[Igofar]

The picture with the red circle is NOT the wire strand going through the small hole in the cartridge, but the solid VARNISH that blocked the hole in the cartridge etc.
And as John pointed out, IF you removed the spring and the seat, it can be put in backwards if you’re not paying attention.
The pictures below are from a professional mechanic who cleaned and said his cartridge looked perfect, and put it back together for the customer, my screen is next to it.
So tell us….did you clean and inspect it this thoroughly, and just take a Quick Look at it?
I find there is often a difference between looking at something and inspecting something.

 

[Igofar]

Fine then, new SMC installed and another ordered. My 2004 Harley is really looking good and cheap to own right now.

That depends if you replaced your cam chain adjusters, bearings, and upgraded your fuel pump to the 07 and newer style models
My 03 CVO is a keeper!

 

[MattSTlouis]

That depends if you replaced your cam chain adjusters, bearings, and upgraded your fuel pump to the 07 and newer style models
My 03 CVO is a keeper!

Mine is carburetor, so no fancy fuel pump but I am actually going to the Harley dealer tomorrow to buy a timing cover gasket to look at the tensioner shoes. I will just put stock shoes back in if they are bad. I have read the second set last longer than the first because the first wear the ruff edges off the timing chain. I bought a new softtail in 03 and put 55k miles on it and never knew this was an issue. Way easier to bleed the breaks on that old technology jalopy too.

 

[MattSTlouis]

Picture's of the filter

 

[Igofar]

Picture's of the filter

You need a picture of the small port to know if fluid was even passing through it, or just bypassing around it.

 

[Igofar]

Mine is carburetor, so no fancy fuel pump but I am actually going to the Harley dealer tomorrow to buy a timing cover gasket to look at the tensioner shoes. I will just put stock shoes back in if they are bad. I have read the second set last longer than the first because the first wear the ruff edges off the timing chain. I bought a new softtail in 03 and put 55k miles on it and never knew this was an issue. Way easier to bleed the breaks on that old technology jalopy too.

Pretty Fat Boy, wrong color though
My last 07 Roadking classic turned 342000 miles when I finally sold it.

 

[sTaylor]

All your brute strength and ……….won’t do anything but Maybe push the pistons off the rotor, which would free up the rear wheel enough to push it off the road to a safe place.
However, it would NOT free up the piston, which would more than likely remain stuck where it is.
And as soon as you pressurized either brake, your starting over.
I’ve seen several rear rotors, brake lines, rear caliper mounting brackets damaged by prying of stuff like a fool.
It it were me….and I didn’t want to damage anything further….and needed to escape the guy with a banjo….of course being a guitarist, I’d probably hang for a while and play a bit….
A much simpler method would be to remove my 8mm box end wrench from the toaster oven, crack the rearmost bleeder, to release the pressure, hop on the bike and ride way to a safe location without Touching either brake….remember your escaping your banjo player, not continuing to ride…
So let’s see…pry stuff and damage more stuff…or loosen one bleeder and don’t touch the brakes till your at a safe spot…
I’ll have to think about this more
But seriously, I would suggest to anyone who had this happen, don’t risk riding the bike, or try to jury rig the brake system.
I’ve opened up more of these units than probably anybody you will ever meet in your lifetime, and have seen them so jammed up that they had to be drilled, tapped, and use a puller to remove the piston.
I doubt you and your friends fingers are that strong.
Be safe, not foolish, I’ve seen more than a couple riders die due to brake issues.

Thank you for the tip on cracking loose the rearmost bleeder. Quick Q: Would you snug the bleeder taught again before heading for/to some semblance of safety? Thanks, Mike G.

 

[MidLife]

Thank you for the tip on cracking loose the rearmost bleeder. Quick Q: Would you snug the bleeder taught again before heading for/to some semblance of safety? Thanks, Mike G.

Depending where you are trying to escape from, not touching the brakes may be difficult.

So it may help to have some options ready...like the hose clamp! Or a fitting to cap the hose.

Or in a pinch....a hose pincher (but you may have to replace the hose afterwards)




You can also consider "starving" the rear, bleed as much as you can out of it. The front reservoir feeds a completely hydraulically isolated brake circuit and you will still have control on 4 pistons on the front if the rear reservoir is empty. The two circuits are hydraulically independent, fluid cannot migrate from the front reservoir to the rear.