Article [13] ST1300 - Secondary Master Cylinder Rebuild- SMC

Joined
Aug 2, 2008
Messages
24
Location
Gig Harbor, WA
Bike
2007 ST 1300
I want to support this posting, as I just worked on my SMC on a 2007 and as you will see from the photos many if not all things that could go wrong did.

Take apart you SMC every 2 or 3 years and service it, I have to replace mine and you do not want to pay for that.

I used this posting to help me take apart the SMC and everything worked as outlined, except I am waiting on parts.

Do not let this happen to you!

Bike SMC issue.jpg Bike SMC SMC piston.jpg
 
Joined
Oct 18, 2007
Messages
901
Location
Huntington Beach, Calif
Bike
2004 st1300
STOC #
7468
Just finished rebuilding my smc with the latest rebuild kit, 45620-mcs-g04. My bike has 45,000 miles on it. At times I could feel the rear brake sticking and knocking of the front caliper.

When I opened the smc if found that other that a little mushrooming of the piston it was not corroded, everything looked very good. So I cleaned everything out , replaced the piston, a little silicone grease and done. Other than the tricky part of getting the snap ring out it was not too difficult.

At the same time I removed all pads front and rear, cleaned all pistons, calipers and springs and applied a little silicone grease around the base of the pistons. Grease on sliding pins on the calipers. Then I bleed the system according to the manual.
Result seems good, rear rotor is not so hot as before. Front smc does not have the free space as before, seems a little tighter. I checked this with one on a new 2012 on the showroom floor and the clearance on the smc seems the same.
Next this weekend a long ride to verify all is good.

I really wanted a complete unit but was told they are on backorder. That would have been a whole lot easier. But thanks to this forum I was given both info and courage to do the job myself and rebuild it.
 
OP
OP
4jranch
Joined
Oct 3, 2009
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757
Location
Brenham, Texas
Bike
'07 ST1300
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8073
Hope it comes out, if not you can always buy the whole MC. You would have to wait for it to arrive though...
 

randalicious

Seasoned M/C Rider
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Nov 30, 2007
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93
Location
~Georgetown, TX
Bike
'07 ST1300
Mine's not as ugly as Tim's, but the piston won't budge. Reminds me of Love Shack -- "Tin roof, . . . rusted." Salt water corrosion? Maybe common on all the bikes in our shipment?

Used compressed air at the bleed port, but couldn't get a good seal on the other outlets. So, N/G.

I'm about to try drilling the piston and tapping it for a 10-32 screw, and pulling it out with that. Opened the rebuild kit already, so no refund. If the bore's too munged up, I'm in for paying for a complete assembly anyway.

Bike's down until something good happens.
 
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randalicious

Seasoned M/C Rider
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Nov 30, 2007
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Location
~Georgetown, TX
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'07 ST1300
Finally, something good happened. My plan to drill and tap a bore into the plunger didn't work after the plunger started to spin because of the pressure of the drill and then the tap. It retreated further down in the SMC bore. So, I used an Easy Out to lock into my drill hole and spin the plunger CCW, while gently pulling up. After several hours of tenderly turning it while putting upward pressure on the EO, it finally started to respond and rise in the SMC bore. After it came out far enough, the spring spit it out of the SMC. Good news, the bore is clean! So, after I dry off from being sweat-soaked, I'll continue with the SMC overhaul, then, the brake system bleeding.

HTH somebody that is having the same problem as I did, and want to pay the diff of a new caliper/SMC with sweat equity. May your garage be air-conditioned.

I couldn't have done it without you, Jeff. :bow1:

I can hardly wait for the next Central TX RTE! Maybe I should say this last thing after I test the brakes. :D
 
Joined
Feb 19, 2007
Messages
45
Location
Sg
STOC #
4085
Hi. thank you for the useful article! Accessing the left front wheel SMC and servicing the cyclinder with new piston will solve the rear brake issues? I experience my rear brake use to wear off much faster then the rest and there was an occasion it got like locked up( without any feel to the rear brakes). I have since got it rectified and did send to a service shop to bleed the fluid. However I feel , it may not be enough. I would seriously consider servicing the SMC if its highly recommended to ensure the rest of the brakes are working properly.
 

randalicious

Seasoned M/C Rider
Joined
Nov 30, 2007
Messages
93
Location
~Georgetown, TX
Bike
'07 ST1300
I would seriously consider servicing the SMC if its highly recommended to ensure the rest of the brakes are working properly.
If the front left brake caliper/SMC does not move smoothly when you press it forward to push the SMC piston further into its bore, the SMC will need to be rebuilt or replaced.
If the SMC does not move at all, the SMC piston is not free to move, and your rear brake is in danger of locking up.
 
Joined
Feb 18, 2005
Messages
150
Location
Fort Worth
Bike
2012 Gold Wing
STOC #
5722
Mine just failed for the second time. The first time it failed at around 12K miles when my bike was 6 months old . It took the two different Honda Shops about 10 visits to figure out what was causing the rear brake to drag. 100K miles later it is doing it again. I guess it is time to rebuild or replace it again.
 
Joined
Feb 18, 2005
Messages
150
Location
Fort Worth
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2012 Gold Wing
STOC #
5722
That bites! Let us know how the repair goes.
Other than bleeding the system being I pain in the butt, I have no complaints. The bike is 10 years old with 113K miles on it, I figure anything can break at time as the miles add up.
 
Joined
Aug 1, 2011
Messages
39
Location
california
Bike
04 st1300
STOC #
8455
Just took mine apart as it was not functioning. Mine was full of a white gooey substance! I was told that could be from moisture. The ports were plugged up with the goo. Also took apart caliper, same story. Wacky stuff. New plunger on order. Anybody seen this goo in their system before?
 
Joined
Aug 27, 2005
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Richardson, TX
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'09 ST1300 ABS
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5914
Sorry I missed this thread, Jeff. I'm with you on taking preventative action to avoid the known problem with the secondary master cyl. At 66,000 miles on my '07, mine failed. The result was a locked up rear brake. The rotor was destroyed, brake caliper damaged, master cyl. a disaster. I had no warning. What happens to create this problem is nicely presented in your photos. Water leaks around the top boot and corrosion starts doing it's dirty work. This isn't obvious when just looking at the secondary master cyl. in it's normal use. Honda changed the design of the secondary master cyl.....in I believe '09 (maybe '08). They added a small channel to allow water to drain off of the top boot.

Thanks for this post. Hope all is well with you guys!

Forest
 
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Mar 26, 2007
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Location
Muskegon, MI
The white goop may be a sign somebody used Dot5 fluid in the system. How long have you owned the bike? You can ask Igofar, as I am not a expert, but I think that is what happens when Dot5 brake fluid is put into a Dot4 system by accident. It gets gummed up as the two fluids are not complatable. Maybe somebody will jump in and confirm this or enlighten us.
 
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Joined
Feb 7, 2009
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Lost in the sticks
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2007 ST1300
Now that I have installed a new SMC, I was wondering how to service the unit other that bleeding the brakes?

What is everyone doing to service the SMC?

Is it to take apart and clean?

How often?

There is nothing in the service manual about when or how to service the SMC.
 

dduelin

Tune my heart to sing Thy grace
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Jacksonville
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GL1800 R1200RT NC700
2024 Miles
006739
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6651
Now that I have installed a new SMC, I was wondering how to service the unit other that bleeding the brakes?

What is everyone doing to service the SMC?

Is it to take apart and clean?

How often?

There is nothing in the service manual about when or how to service the SMC.
Flush and replace hydraulic fluid every 12,000 miles or two years. No short cuts - remove and tilt the LF caliper assembly as detailed in SM and elsewhere. Repeat as needed. That's all the SMC needs besides keeping the drain hole or channel clear.
 

Gus1300

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Apr 5, 2007
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Haymarket VA
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04 1300A
Do you recall how many copper crush washers there were on all of the front hoses going to that left caliper? Did you replace those or just reuse them. (One of my pet peeves is the price they charge for a simple copper washer).
If you're not aware, copper crush washers can be annealed by heating to cherry hot with a torch and quenching. Unlike hardening other metals, this softens the copper from its used/hardened state.
 
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DOT 5 brake fluid is not backward compatible with DOT 4, it's silicone based. Even if flushed...the problem with using DOT 5 comes when used with ABS. It foams and really doesn't work in ABS systems.....
 
Joined
Apr 2, 2012
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Council Bluffs IA
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Flush and replace hydraulic fluid every 12,000 miles or two years. No short cuts - remove and tilt the LF caliper assembly as detailed in SM and elsewhere. Repeat as needed. That's all the SMC needs besides keeping the drain hole or channel clear.
The annealing process does not require quenching, but is done to removing scaling. I would not quench it.
 
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Murça
Secondary Master Cylinder Rebuild- SMC

This is a job that probably all ST1300's over 5 years old need to consider. A regular addition of silicon grease into the outer boot might be excellent preventive maintenance. Forest had warned me of this problem but I really didn't understand the problem until Lynne's rear brake began locking up, enough to damage the rear disc and toast the rear piston seals. With a more thorough research of this site I was able to understand the problem. This really helped as I was able to direct the service manager as to the real problem when we took her bike in for repair under the extended warranty. The repair took three weeks but was finally completed. I felt that I needed to get mine done before my ST had similar results. I would recommend doing this job when you are replacing all the brake fluid.

Here is the front left brake caliper removed, the SMC is on the top. The push rod is on top with the bolt partly reinserted.



The manual recommends removing the entire left front caliper to work on it but I thought I might be able to rebuild it in place and avoid draining all the brake fluid. Good idea but I was not able to get the snap ring out so I took the caliper off. You will need to loosen the brake hose oil bolts before removing the caliper from the attachments to the wheel as they can be very tight.






After removing the caliper I completed removal of all the oil bolts and let the brake fluid drain into a container on the floor.




So now just to pull the boot back and take out the snap ring... It was really stuck so using a vise grip on the eye end and a 10mm wrench under the boot I just took apart the push rod assembly. Now I had direct access to the snap ring, it was still hard to remove. A good, high quality snap ring tool would be a good investment.



Now the push rod and the master piston could be removed. Note the crude and corrosion.




Cleaning out the cylinder would be hard while still attached to the brake lines

Here are the new parts and tools you will need. All the parts come in the piston set 45620-MCS-G03



Soaking the master piston and seal in brake fluid is good before installation. I also found it necessary to take apart the new push rod assembly to get the
push rod and snap ring in place, it was fairly tight.



The boot and eyelet end are easy to replace after the push rod is in place.
I put lots of silicon grease under the boot.



Now you are ready to reattach the brake lines and brake caliper. I then refilled and bled all the brake lines per the standard sequence. It did take some time to get all the air out, I did it twice. Always a circus to go through that complex sequence....
Excelente post... Obrigado
 
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Estou muito contente com o vosso trabalho em favor dos homens das motos... Obrigado a todos!...
 
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Jan 15, 2020
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Murça
[CITAÇÃO = "fnmag, post: 2201298, membro: 17783"]
Bem-vindo ao fórum ST-Owners Jose.
Bon dia.
[/ CITAR]
Obrigado
. Depois de muitos anos a andar de moto .. nunca tive um problema que me tivesse preocupado .. Estou pensando ... Porque não, quando nas vossa viagens, não podem passar por Portugal, sendo meus convidados (1 ou 2 dias) na minha casa humilde casa em Portugal .... Situada numa linda região ....? Com um abraço
 
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