Anyone de-linked the brakes?

If it were me, and I was told the bike I just purchased had a REBUILT SMC, and had brake issues prior to me purchasing it, and the rebuild was an attempt to fix/correct the brake issues, I would Replace the SMC as an entire unit, service the brake system properly, including a complete flush and bleed. But that's just me, since I know that "rebuilding" it is just a temporary fix, and often does not correct the problem.
I don't like surprises that leave me stranded on the side of the road or worse.

jfheath said:

The test is whether or not the brakes release by themselves AFTER they have been applied by the SMC. The problem is that if the pressure cannot escape through the tiny compensation port efficiently then they cannot release when extra pressure builds up due to heat expansion in the fluid.

So no. Just spinning the back wheel is a start, but it doesn't prove anything of any significance.

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So simply check it after you’ve ridden it and pumped the rear pedal?

Igofar said:

If it were me, and I was told the bike I just purchased had a REBUILT SMC, and had brake issues prior to me purchasing it, and the rebuild was an attempt to fix/correct the brake issues, I would Replace the SMC as an entire unit, service the brake system properly, including a complete flush and bleed. But that's just me, since I know that "rebuilding" it is just a temporary fix, and often does not correct the problem.
I don't like surprises that leave me stranded on the side of the road or worse.

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If I decided to do that, what other that else (other than #18) would I need?

#18 is the delay valve. Not the SMC.

2007 Honda ST1300A A LEFT FRONT BRAKE CALIPER ('07) | Ron Ayers

The SMC would be part #2 in the above link to the left front brake caliper fiche.

You would also need part numbers 23 and 24. These are the pivot bolts which accoording to Honda have to be replaced every time they are removed. Some people use loctite and re-use them, but since you ddon't know anything about the bike's history, I would get new.

You also need a handful of copper/aluminium washers for the brake hose banjo unions. 2 per joint. I think that makes 6.

Check the year of your bike from the label under the seat. The design of the SMC changed after 2007.
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Edited version of the image on the fiche showing parts #2, 23 and 24.



Part #2 comes pre-assembled - like this 2009 version. Beware the different part numbers. Before 2008 has the number 06454-MCS-G03. 2008 and later, the SMC ends R02.
They are very different, but it is difficult to spot in a photo. The pre 2008 versions have a small hole in the casting on the side, just below the rubber boot.



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Part #18 on your link is the delay valve - is located behind the right fork leg just above mudguard height. It is a device that stoped the rear pedal applying the centre piston on the front right brake caliper at 'normal' pedal pressure. It opens up to add extra braking force when the pedal is pressed harder.

This has nothing to do with the SMC.

And yes, you can also de-link, as described elsewhere in these forums, which will eliminate SMC malfunctions, but it won't cure any hardware problems with the calipers or bracketry. If your rear brake has been dragging, for instance, there's an excellent chance it needs as rebuild or a piston cleaning.

Where can I get more good tubing for bleeding? The crap I get from hardware store doesn’t stay on the nipple very well

Auron said:

Where can I get more good tubing for bleeding? The crap I get from hardware store doesn’t stay on the nipple very well

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Tygon fuel line from an auto parts store or small engine repair shop or possibly from a lawn equipment dealer with a good parts department. The latter is where I get it.

Are you using the clear 3/16 X 5/16 tubing from the hardware store?
I've never had an issue with it, however, some batches of it tend to run tighter than others depending on vender.
If yours is tight and hard to press on the nipple, you could gently use a heat gun, or hair dryer so soften it up a bit, push it on, then when it cools its a tight/snug fit.
We're just talking a few seconds of heat.

A tip for keeping your bleed hose line on the bleed nipple...... use these spring clamps over the end, it helps keep it attached.. less frustration.
Been doing for years.... Amazon has various sizes. I keep a stash of different sizes handy for whatever work I am doing...

Here in Coquitlam I go to Lordco Auto Parts and get the braided black fuel line, it comes in every ID / OD. Then you want to get the clear vinyl tubing, thin wall also in various IDs, then you want to go to Pacific Controls and get some proper pneumatic barb fittings, not those arrow ones, but the old controls style type. Then, with a barb coupling or reducing coupling, you can make a nice short braided black to clear vinyl adapter so you can obtain a seal on the bleed fitting and still see the fluid. It's a complete PITA, but then you've got it as a kit.

Igofar said:

Are you using the clear 3/16 X 5/16 tubing from the hardware store?
I've never had an issue with it, however, some batches of it tend to run tighter than others depending on vender.
If yours is tight and hard to press on the nipple, you could gently use a heat gun, or hair dryer so soften it up a bit, push it on, then when it cools its a tight/snug fit.
We're just talking a few seconds of heat.

Click to expand...

Is tygon fuel tubing more stretchy? The stuff from the hardware store seems really stiff. But I also haven’t tried heating it up like you said

Auron said:

Is tygon fuel tubing more stretchy? The stuff from the hardware store seems really stiff. But I also haven’t tried heating it up like you said

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Tygon fuel line is more like silicone rubber than vinyl plastic.