Yet another SMC question/theory

beeker · Apr 9, 2016

Jethro77 said:
Ordered a replacement SMC bracket today from HondaPartsDirect.com today $146 plus shipping $20 was the cheapest I could find but the delivery is going to take a week +.... I might have been better served to order it from someone else... but hard to say if anyone would have gotten it to me earlier... well apparently I'll be down 2-3 weeks with this issue, I'm already going through motorcycling withdraw...

Hi Jethro77,
I finished last season with dragging rear brake and rebuilt the SMC over the winter. My bike is an '04 and I had a hard time deciding whether to upgrade the entire SMC cylinder or just buy a rebuild kit. In the end I purchased a kit as I could not find anyone who could tell me if the latest evolution of the SMC cylinder is any different than the original. This is a pic of my original cylinder after clean up. Part suffix would have been G01. Could you post photo of the new cylinder when you receive it (although it might come assembled) along with the part number for comparison?
Thanks
Dennis

Kiltrochan2 · Apr 10, 2016

Hi Guys
Looking to see if anyone can answer my query about the SMC and bleeding the system.
Everything that I’ve read says that when bleeding the linked brake to the rear, the SMC / front left caliper should be unbolted from the wheel and tilted at an angle of 15 degrees. My understanding is that this replicates the piston movement in the SMC and allows fluid to flow to the rear caliper.
Today I wanted to check that the SMC was working and used a “G” clamp to compress the SMC bracket (still attached) towards the front fork which compressed the plunger / piston in the SMC.
The rear wheel locked solid and on release of the “G” clamp the rear wheel turned freely.
This seemed a whole lot quicker and simpler than removing the SMC to tilt it.
Before I bleed the brakes, is there something I’ve missed which requires it to be removed to carry out this procedure or would it work as I described.
Thanks

David

dduelin · Apr 10, 2016

Kiltrochan2 said:
Hi Guys
Looking to see if anyone can answer my query about the SMC and bleeding the system.
Everything that I’ve read says that when bleeding the linked brake to the rear, the SMC / front left caliper should be unbolted from the wheel and tilted at an angle of 15 degrees. My understanding is that this replicates the piston movement in the SMC and allows fluid to flow to the rear caliper.
Today I wanted to check that the SMC was working and used a “G” clamp to compress the SMC bracket (still attached) towards the front fork which compressed the plunger / piston in the SMC.
The rear wheel locked solid and on release of the “G” clamp the rear wheel turned freely.
This seemed a whole lot quicker and simpler than removing the SMC to tilt it.
Before I bleed the brakes, is there something I’ve missed which requires it to be removed to carry out this procedure or would it work as I described.
Thanks

David

The procedure to tilt the SMC moves its fluid outlet to the rear wheel higher than the inlet so that flushing the system completely removes accumulated moisture or debris from the SMC bore where it accumulates over time. It has nothing to do with replicating piston movement. In fact you want the SMC inlet and outlet open so that new clean fluid moves unhindered through the SMC - you don't want the SMC compressed during this effort.

sky.high · Apr 10, 2016

dduelin said:
My Mityvac has bled my ST about 14 times and I never have any help on levers or pedals. I do use a three foot long piece of broom stick to pump the foot brake from the left side of the bike. Just saying more than one way to skin a cat.

, not quite 14 times though but just done mine with Mityvac and it worked fine, works perfectly on all my other bikes and vehicles, just replaced the front callipers on my 2500HD Chev, what's not like

Kiltrochan2 · Apr 11, 2016

dduelin said:
The procedure to tilt the SMC moves its fluid outlet to the rear wheel higher than the inlet so that flushing the system completely removes accumulated moisture or debris from the SMC bore where it accumulates over time. It has nothing to do with replicating piston movement. In fact you want the SMC inlet and outlet open so that new clean fluid moves unhindered through the SMC - you don't want the SMC compressed during this effort.

Thanks for the info dduelin. I should have known it would be too good to be true.

David

Igofar · Apr 11, 2016

sky.high said:
, not quite 14 times though but just done mine with Mityvac and it worked fine, works perfectly on all my other bikes and vehicles, just replaced the front callipers on my 2500HD Chev, what's not like

Wait a couple days then bleed the system manually with a motion pro tool and you may be surprised at the air left in your system by your misty vac.
.02

dduelin · Apr 11, 2016

If the brakes are good and firm after being flushed and bled with a vacuum device why would you see the need to go back and bleed the brakes again to check for air? Air in the system would be apparent by feel at the lever or pedal. In the case of the ST1300 with the rear caliper fed by two subsystems out of one reservoir the brake pedal feel alone will tell you if one of these circuits has air in it.

Vacuum pumps often pull tiny amounts of air through the bleeder threads right at the fitting and it looks like it's pulling air out of the system from further back upstream when it's not. Teflon tape on the bleeder threads will stop or reduce it or just know this occurs and don't worry about it when the end results are good.

Igofar · Apr 11, 2016

I am not suggesting that it is needed, and I agree that you should be able to feel air in the system at the lever etc. However, I have had several members bring their bikes to me after a dealer or friend bled the system with a mity vac telling me their brakes felt fine, only to be shown that there was still air in the system and that the brakes felt even better after this was removed.
I have used many types of bleeding system tools over the years and I personally feel you get a better bleed with a check valve.
This is just my personal choice.

dduelin · Apr 11, 2016

I think that if a dealership is held up as a paragon of service excellence the reality in too many cases is bitter disappointment. Not just on motorcycles but many fields.

I know the mechanic that works on my bike and he knows how to use a vacuum pump. If the dealership didn't know how to properly use one and properly service the ST1300 LBS system ( two separate and discrete processes ) the outcome would be less than optimal.

However, that has nothing to do with a MityVac leaving air in the system. Used properly it will not.

Igofar · Apr 11, 2016

Lets agree to disagree on this point....
ok folks lets move on there is nothing to see here :rofl1:

RaYzerman · Apr 11, 2016

Igofar said:
Lets agree to disagree on this point....
ok folks lets move on there is nothing to see here

I'm OK with that. I think all three methods are fine in competent hands.

Jethro77 · Apr 17, 2016

Thank you all for your help and sggestions, I have just installed and successfully tested my new SMC assembly (06454-MCS-R02). Went on without a hitch and re bled the system...

Bleeding went much faster and easier this time since I had just done it 2 weeks ago with the help of Igofar and I now had a new motion pro bleeder and the help of a freind....

Unfortunately the rear brake is soft and I will have to bleed the it again, I expect the next attempt to go perfectly...

Jethro77 · Apr 18, 2016

I re bled the system last night and all went well, it seems that I underestimated the amount of air the new SMC put in the brake lines.... I even ended up swapping out a bleeder valve thinking that it was suckling air from somewhere... naive thought...

Anyway I now have a firm rear brake pedal and I'm a happy man again... unfortunately the test ride will have to wait until later since I got conned into helping my brother in law do farm work the next couple days....

Thanks to this wonderful site and especially Igofar for all the assistance!

jonjonboo · Apr 18, 2016

dduelin said:
I think that if a dealership is held up as a paragon of service excellence the reality in too many cases is bitter disappointment. Not just on motorcycles but many fields.

I know the mechanic that works on my bike and he knows how to use a vacuum pump. If the dealership didn't know how to properly use one and properly service the ST1300 LBS system ( two separate and discrete processes ) the outcome would be less than optimal.

However, that has nothing to do with a MityVac leaving air in the system. Used properly it will not.

MiteyVac has several different types of brake tools and of course the more expensive air compressor driven models are better. I have used the hand pump version and did get a bit of air in the system, after being disappointed with that model I purchased a large air compressor and the $150 miteyVac air driven brake bleeder. The newer more expensive model works great and I have never had air sucked into my brake system, do all my vehicles with this bleeder. Can't even imagine trying to use a check valve to remove that much fluid by pumping levers and or pedals.

Tom Mac 04a · Apr 19, 2016

Now your get to test the warm rotor with the finger test !

Yet another SMC question/theory

beeker

Kiltrochan2

dduelin

Tune my heart to sing Thy grace

sky.high

Kiltrochan2

Igofar

dduelin

Tune my heart to sing Thy grace

Igofar

dduelin

Tune my heart to sing Thy grace

Igofar

RaYzerman

Jethro77

Jethro77

jonjonboo

Tom Mac 04a

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