Andrew Shadow
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Did you simply cross-drill the rear caliper so that all three rear pistons are operated by the foot pedal?
Notice any significant difference in braking characteristics?
Article [13] ST1300 - Secondary Master Cylinder Rebuild- SMC
- Thread starter 4jranch
- Start date
Notice any significant difference in braking characteristics?
ChucksKLRST
Team Colorado
Stopped by my Local Honda shop, (even though I don't own a Honda any more) They had a customers 2012 ST1300 in the shop for SMC repair/replacement. They told me that it was being covered by Honda. So did Honda finely recognize the failure of their ways?
The hole is drilled in the back of the piston cylinder. yes all pistons operate from rear brake. I would say it softens the rear brake a little. JME
Pictures please?
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- Sep 24, 2018
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Where does it relieve the pressure to, if pressed to hard....??
Wouldnt the smc put additional pressure needing to be relieved?
I thought the prop valve was off rear master cyl, not caliper??
No drawing in front of me so going from memory...lol
Wouldnt the smc put additional pressure needing to be relieved?
I thought the prop valve was off rear master cyl, not caliper??
No drawing in front of me so going from memory...lol
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Hello
My name is Marcin and Im looking here for some help.
Last year my SMC start to be loud and sometimes lock my rear wheel.
Unfortunatelly from health issues I had to leave bike for half year in garage and few days ago I have starter a repair.
I bought 45620-MCS-G04 repair kit for SMC from Honda, dismount front left caliper, replaced parts, clean everything (including filter cartridge inside).
I dismounted rear caliper, clean and grease what necessary.
Dismounted also rear foot brake pump (rear master cylinder), clean & grease.
Now I have problem. I cannot bleed system. Whole the time rear brake leaver is spongy and soft. And what worst after using rear brake or SMC (by hand) it locks wheel and it is hard to turn it. Im reversing rear brake pads without any problem (everything is runnig smooth) and once again, using any brake and it locks the wheel.
Right now Im wondering if I put filter cartride that is mounted on front SMC in correct way. In one way it has full flow (very tiny hole and bigger one with valve), and other way limited flow (only by tiny hole).
Maybe someone can show me how it should be mounted? Full flow into the SMC, or out? I have found some topics here regarding that but unfortunately I doint understand well. I want to be sure.
UPDATE:
Below picture of correct way of installing the filter cartride.
My name is Marcin and Im looking here for some help.
Last year my SMC start to be loud and sometimes lock my rear wheel.
Unfortunatelly from health issues I had to leave bike for half year in garage and few days ago I have starter a repair.
I bought 45620-MCS-G04 repair kit for SMC from Honda, dismount front left caliper, replaced parts, clean everything (including filter cartridge inside).
I dismounted rear caliper, clean and grease what necessary.
Dismounted also rear foot brake pump (rear master cylinder), clean & grease.
Now I have problem. I cannot bleed system. Whole the time rear brake leaver is spongy and soft. And what worst after using rear brake or SMC (by hand) it locks wheel and it is hard to turn it. Im reversing rear brake pads without any problem (everything is runnig smooth) and once again, using any brake and it locks the wheel.
Right now Im wondering if I put filter cartride that is mounted on front SMC in correct way. In one way it has full flow (very tiny hole and bigger one with valve), and other way limited flow (only by tiny hole).
Maybe someone can show me how it should be mounted? Full flow into the SMC, or out? I have found some topics here regarding that but unfortunately I doint understand well. I want to be sure.
UPDATE:
Below picture of correct way of installing the filter cartride.
Last edited:
Something is wrong with your brake system then. Both the hand lever, and the foot pedal should be firm after bleeding in a good working system.
Have you inspected/checked the other parts of your brake system?
Have you ever removed or inspected the REAR master cylinder? I've found these need to be serviced/rebuilt from time to time.
And lastly, have you rebuilt the calipers? Removed the pistons and looked behind them? I often find jellied goop behind pistons, after folks simply cleaned what they could see, and thought they were finished etc.
Even though you may clean the body of the caliper, and polish the pistons clean, you never know what lurks behind the pistons if you don't pop them out from time to time and clean behind them!
Something is wrong with your brake system then. Both the hand lever, and the foot pedal should be firm after bleeding in a good working system.
Have you inspected/checked the other parts of your brake system?
Have you ever removed or inspected the REAR master cylinder? I've found these need to be serviced/rebuilt from time to time.
And lastly, have you rebuilt the calipers? Removed the pistons and looked behind them? I often find jellied goop behind pistons, after folks simply cleaned what they could see, and thought they were finished etc.
Even though you may clean the body of the caliper, and polish the pistons clean, you never know what lurks behind the pistons if you don't pop them out from time to time and clean behind them!
I completely disassembled all 3 calipers the last time I replaced the fluid and cleaned them out. I religiously change fluid every 12k miles. I have not accessed the rear master yet. Currently the rear pedal and front lever give a nice solid feel. Once I'm done with everything and get to riding again I will let you know how it does.
Idle curiosity, why does the rear master not get a banjo bolt connection to the rear brake like the rest of the brake system?
I didn't realise that I had contributed to this post before - but it seems to be populated with a few of my photos and diagrams - not that I mind that one bit, they just took me by surprise.
@martinpl In a post of 7th April 2020 (shown as post #57 on my screen) - you have reproduced one of my braking circuit diagrams and circled the SMC inlet port.
Underneath, you have drawn that one way valve. But you have drawn it the wrong way round !.
[edit] @martinpl has checked this out and come to the same conclusion. Post #57 is now showing the correct orientation [/edit]
I think in case anyone else looks in and thinks that your diagram is correct, you might want to put it the correct way round. Use this if you like.
More info and pics of the dodgy SMC and of the inlet port one way valve cartridge (and the above full sized diagram) are here:
www.st-owners.com
Note the photo of the inlet port in the above link, taken immediately after taking off the black cover. The 'O' ring is still in place. Note that this is the side with the white gauze. The other side has a blue plastic clip-on cover. I verified this when I removed my own SMC a couple of years later - not touched since new. Mine was spotless !!
But really, if your SMC has got to the point where this valve is clogged, it really is time to replace the SMC - and learn to look after it better than the previous owner !
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The proportional control valve sits in the braking system for the rear circuit between the SMC and the two outer pistons of the rear caliper.
The SMC operates those two outer pistons if the bike is in motion (as the SMC rocks forward whenever the front left brake is applied - which means when either the front lever or the rear pedal is operated). ie when braking, the SMC will operate the rear outer pistons. When the bike is stationary, the SMC cannot rock forward, but the fluid from the rear brake pedal will operate the outer pistons in the rear caliper. If you want to see how the circuit operates, then the diagram that @martinpl reproduced above can be found in the link below - intended for bleeding, but it shows what fluid is moving, which pistons are operated and where the fluid comes from.
www.st-owners.com
The proportional control valve is essentially a piston which moves inside a chamber. Normally, the piston remains closed under pressure of a strong spring. However, when braking force increases to the point where the rear wheel would be at risk of locking up, the spring gives way and gets pushed back into its chamber, relieving pressure from the rear outer pistons. It is actually a bit more complex than that, but that is the gist of it. Basically if you press too hard, the pressure is released before the brakes can lock.
This is completely different from the system which relieves the pressure from the pistons when the pedal/lever is released or due to expansion of the fluid due to heat. That is the tiny compensation port that exists in every master cylinder - the front brake MC, the rear brake MC, the clutch MC and yes, the Secondary MC.
For more information on this, see this link.
www.st-owners.com
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@martinpl In a post of 7th April 2020 (shown as post #57 on my screen) - you have reproduced one of my braking circuit diagrams and circled the SMC inlet port.
Underneath, you have drawn that one way valve. But you have drawn it the wrong way round !.
[edit] @martinpl has checked this out and come to the same conclusion. Post #57 is now showing the correct orientation [/edit]
I think in case anyone else looks in and thinks that your diagram is correct, you might want to put it the correct way round. Use this if you like.
More info and pics of the dodgy SMC and of the inlet port one way valve cartridge (and the above full sized diagram) are here:
Article [13] - ST1300 - Brake Maintenance - Photos of dismantled SMC | ST1300 Articles
A faulty SMC, taken apart, sawn lengthways, with labelled photos and a commentary. This SMC had a brand new service kit fitted not long before it failed again. A while ago I posted a query concerning some weird behaviour on a friends braking system. The symptoms were that in spite of getting...
Note the photo of the inlet port in the above link, taken immediately after taking off the black cover. The 'O' ring is still in place. Note that this is the side with the white gauze. The other side has a blue plastic clip-on cover. I verified this when I removed my own SMC a couple of years later - not touched since new. Mine was spotless !!
But really, if your SMC has got to the point where this valve is clogged, it really is time to replace the SMC - and learn to look after it better than the previous owner !
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The proportional control valve sits in the braking system for the rear circuit between the SMC and the two outer pistons of the rear caliper.
The SMC operates those two outer pistons if the bike is in motion (as the SMC rocks forward whenever the front left brake is applied - which means when either the front lever or the rear pedal is operated). ie when braking, the SMC will operate the rear outer pistons. When the bike is stationary, the SMC cannot rock forward, but the fluid from the rear brake pedal will operate the outer pistons in the rear caliper. If you want to see how the circuit operates, then the diagram that @martinpl reproduced above can be found in the link below - intended for bleeding, but it shows what fluid is moving, which pistons are operated and where the fluid comes from.
Article [13] - ST1300 - Brake Maintenance - Getting all the air out of the brake system | ST1300 Articles
A detailed look at the process of getting the air out of the Honda ST1300 brake lines. A sequence of diagrams of the brake circuits, colour coded to show which parts of the system are being accessed when each bleed valve is opened and explanations of where the trouble spots are. These are just...
The proportional control valve is essentially a piston which moves inside a chamber. Normally, the piston remains closed under pressure of a strong spring. However, when braking force increases to the point where the rear wheel would be at risk of locking up, the spring gives way and gets pushed back into its chamber, relieving pressure from the rear outer pistons. It is actually a bit more complex than that, but that is the gist of it. Basically if you press too hard, the pressure is released before the brakes can lock.
This is completely different from the system which relieves the pressure from the pistons when the pedal/lever is released or due to expansion of the fluid due to heat. That is the tiny compensation port that exists in every master cylinder - the front brake MC, the rear brake MC, the clutch MC and yes, the Secondary MC.
For more information on this, see this link.
Article - Brakes - Operation of the Master Cylinder | Articles
The operation of a hydraulic master cylinder - as used for the front brake lever, rear brake pedal, clutch lever and SMC. Coloured diagrams and explanations. 1 - 'Relaxed' Brake Master Cylinder (ie Brakes are not Applied) The image shows the front master cylinder and the reservoir...
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It does, its behind the side step panel.
2010 Honda ST1300AA Rear Brake Master Cylinder (St1300a)
Shop online for OEM Rear Brake Master Cylinder (St1300a) parts that fit your 2010 Honda ST1300AA, search all our OEM Parts or call at 252-758-3084
www.ronayers.com
Two Banjo Unions, one double length bolt.
In situ. The one to the front brake goes on top. The one to the rear goes underneath.
In situ. The one to the front brake goes on top. The one to the rear goes underneath.
Thanks JohnTwo Banjo Unions, one double length bolt.
In situ. The one to the front brake goes on top. The one to the rear goes underneath.
Thank you for answer. I have found correct way using trial-and-error method
I have replaced picture with second one with correct position of valve.
Suraj
GoSteelers
Is there any quick way to get the air out after replacing the part as mentioned in the original post?
I successfully replaced the the SMC piston without having to completely remove the caliper or drain fluid from other cylinders. Only place that I have air is in the SMC. I want to avoid taking the fairing off if possible. I replaced the brake fluid with completely bleeding the system <200 miles ago and don't want to go through the process again if I don't have to. Also replaced the coolant while I was at it. Any inputs to this would be appreciated.
Everything that could go wrong on this motorcycle has gone wrong in 2020 for me. Clutch slave cylinder, rear brakes dragging and SMC not rebounding.
I successfully replaced the the SMC piston without having to completely remove the caliper or drain fluid from other cylinders. Only place that I have air is in the SMC. I want to avoid taking the fairing off if possible. I replaced the brake fluid with completely bleeding the system <200 miles ago and don't want to go through the process again if I don't have to. Also replaced the coolant while I was at it. Any inputs to this would be appreciated.
Everything that could go wrong on this motorcycle has gone wrong in 2020 for me. Clutch slave cylinder, rear brakes dragging and SMC not rebounding.
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"IGOFAR to the front desk please"
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Due to the high volume of calls on the white courtesy phone, you may experience extended call times.
Please be patient, your call is important, and will be answered in the order it was received.....
Sounds like Larry needs one of those professional answering companies to screen his calls!
The only one you need to get at that isn't exposed is the one near the Proportional Control Valve. That is just below the bottom edge of the fuel tank on the right hand side.
if you undo the main right hand fairing bolt, undo the two bolts in the right fairing pocket and release the right hand inner cowl, you can ease the middle fairing away enough to access the bleed valve.
Personally, i prefer to take off the middle cowl. My hands are too big to go fiddling around in small places.
But you need to go round the sequence as described. Ignore the bits that are fed from the front master cylinder reservoir - ie the front top bleed valves on both front calipers. They are a separate circuit. But in replacing the SMC, air will have got into the other lines, so you must bleed that complete circuit in the correct order. You may have to go round a couple of times
This may help - already posted earlier, but here it is again.
www.st-owners.com
if you undo the main right hand fairing bolt, undo the two bolts in the right fairing pocket and release the right hand inner cowl, you can ease the middle fairing away enough to access the bleed valve.
Personally, i prefer to take off the middle cowl. My hands are too big to go fiddling around in small places.
But you need to go round the sequence as described. Ignore the bits that are fed from the front master cylinder reservoir - ie the front top bleed valves on both front calipers. They are a separate circuit. But in replacing the SMC, air will have got into the other lines, so you must bleed that complete circuit in the correct order. You may have to go round a couple of times
This may help - already posted earlier, but here it is again.
Article [13] - ST1300 - Brake Maintenance - Getting all the air out of the brake system | ST1300 Articles
A detailed look at the process of getting the air out of the Honda ST1300 brake lines. A sequence of diagrams of the brake circuits, colour coded to show which parts of the system are being accessed when each bleed valve is opened and explanations of where the trouble spots are. These are just...