The dreaded Rear Brake Master Cylinder... I need a replacement. Any ideas?

[SKR]

So, my new to me 08 unfortunately has come down with rear brake drag. It's been in the shop for 6 weeks, most of that waiting on parts. Calipers and pistons were replaced (they needed it), and then rear brake master cylinder rebuild kit when that didn't work. Still won't hold pressure. I've seen the various threads of others going through this saga.

The next step appears to be replacing the rear brake master cylinder assembly altogether. Parts are an issue though, and most places I've seen in the US have it as unavailable. I see a few in Europe but am worrying they just haven't updated their inventory to show it out of stock.

Any ideas on where I can get my hands on an rear brake master cylinder assembly? Part number 43510-mcs-r01

Trying to get it ready for a booked vacation in September so I can get a little bit of riding out her this year, but starting to worry...

 

[Upt' North]

So, my new to me 08 unfortunately has come down with rear brake drag. It's been in the shop for 6 weeks, most of that waiting on parts. Calipers and pistons were replaced (they needed it), and then SMC rebuild kit when that didn't work. Still won't hold pressure. I've seen the various threads of others going through this saga.

The next step appears to be replacing the SMC assembly altogether. Parts are an issue though, and most places I've seen in the US have it as unavailable. I see a few in Europe but am worrying they just haven't updated their inventory to show it out of stock.

Any ideas on where I can get my hands on an SMC assembly? Part number 43510-mcs-r01

Trying to get it ready for a booked vacation in September so I can get a little bit of riding out her this year, but starting to worry...

Others will be along to advise on the peculiarities of the SMC but have you tried Dave Silvers in the States. They will advise on availability etc.
Upt'North.

 

[SKR]

Others will be along to advise on the peculiarities of the SMC but have you tried Dave Silvers in the States. They will advise on availability etc.
Upt'North.

I sent em' an email. Thanks!

 

[ST Gui]

It's no surprise that a dealer wouldn't stock a SMC but it being 'unavailable' from Honda is a little disturbing. You know it will happen eventually but it's still a bit of a shock when it finally does.

 

[pmatulew]

Do you hear that? I think the white courtesy phone is ringing.

 

[jfheath]

43510-mcs-r01 is discontinued in Europer too

Fortunately it has been replaced by part 43510-mcs-r02 - which is simply a slight upgrade. Some sites haven't updated their fiches - locate the part r01 which reports that it isn't available.

 

[aniwack]

Sounds like he needs to call 1-800-IGOFAR. I recently had to rebuild mine from the seals up. Larry will walk you through the entire process for breakdown and refit.

 

[ST Gui]

Fortunately it has been replaced by part 43510-mcs-r02 - which is simply a slight upgrade.

Anxiety instantly relieved and the Xanax saved for another day. Thanks for that!

 

[dduelin]

The latest part number is 06454-MCS-R02 and it is in stock in the USA. I just checked it, it's in multiple Honda warehouse locations.

A search for the superseded 06454-MCS-R01 would turn up mostly likely nothing, 'cuz it's not available anymore.

 

[caldercay]

Any ideas on where I can get my hands on an SMC assembly? Part number 43510-mcs-r01

I'm a bit confused. You state "SMC assembly" and then give a part # for the rear brake (Master Cylinder Sub-Assy, RR). The SMC is found as a component of the left front caliper.

 

[SKR]

I'm a bit confused. You state "SMC assembly" and then give a part # for the rear brake (Master Cylinder Sub-Assy, RR). The SMC is found as a component of the left front caliper.

The courtesy man himself called me and gave me some great tips and notes to work with. I need to get the bike towed back to me from the shop before I can do much, but more to come

The shop is claiming that the rear brake master cylinder, not the secondary master cylinder, is worn and allowing air to enter the system. They're claiming this is causing the rear brake not to hold pressure. They say that it will depress the pistons fine, fluid is getting everywhere it needs to be, but releasing the brake is allowing air back into the system because of the worn cylinder.

Also as an aside, I don't see a 43510-mcs-R02 anywhere. Legitimately concerned that there is a part no longer made for the rear brake master cylinder. I asked for pictures of the wear, one way or another I'll update on that.

 

[SKR]

Also, updated OP - i have some terminology wrong here. I said SMC and should've been saying rear brake master cylinder. That's on me!

 

[jfheath]

I was just commenting on that. You said SMC, but the part number is for the rear master cylinder, which I hadn't spotted.

Worth trying though - the R01 version of the SMC was out of stock a couple of years ago, and still some suppliers list it as the part for some bikes, and do not give the alternative R02.

Im wondering if they stopped buying the updated fiches ?

Try looking on the fiches for the last model to be produced. In the Uk that was the AE in 2014. That fiche lists the later SMC part and the later radiator (which fits earlier models and is £100 cheaper!)

Hang on - i'll go to my pc and take a look

In fact this appears in all the fiches I tried back to 2006 - ABS and non ABS - this from a large UK supplier for a 2014 model in the UK just now.



David SIlver is the only company that I know of that is able to tell you the precise part for a model based on the frame number. For example, when I was looking for a new radiator, they said - we need your frame number. I reassured them that mine was an A9, built in 2013. They told me the radiators changed part way through that year. If I gave them my frame number, they could look up which radiator it needed.

 

[SKR]

Hmm. 43510-MCS-G02 does look like the same thing, but it only shows on 2007 and Police models. Not 2008. Any issues you think on using it on 2008? Very confusing.

Speaking with Igofar a little more, he thinks they're the same part - just different vendor supplying the police bikes hence the different number. The diagrams are identical, though I wouldn't want to trust my life on the diagrams alone.

 

[dduelin]

I was just commenting on that. You said SMC, but the part number is for the rear master cylinder, which I hadn't spotted.

Worth trying though - the R01 version of the SMC was out of stock a couple of years ago, and still some suppliers list it as the part for some bikes, and do not give the alternative R02.

Im wondering if they stopped buying the updated fiches ?

Try looking on the fiches for the last model to be produced. In the Uk that was the AE in 2014. That fiche lists the later SMC part and the later radiator (which fits earlier models and is £100 cheaper!)

Hang on - i'll go to my pc and take a look

In fact this appears in all the fiches I tried back to 2006 - ABS and non ABS - this from a large UK supplier for a 2014 model in the UK just now.



David SIlver is the only company that I know of that is able to tell you the precise part for a model based on the frame number. For example, when I was looking for a new radiator, they said - we need your frame number. I reassured them that mine was an A9, built in 2013. They told me the radiators changed part way through that year. If I gave them my frame number, they could look up which radiator it needed.

Any authorized Honda dealer should be able to do this but it only comes into play if Honda does change a part number during a model year which is very rare. Honda provides computer links to authorized dealers and retailers which allow entry into the Honda global parts inventory network. If a part is VIN specific all dealers know it or should know it. If David Silver was the sole supplier on the planet for the right part that would put 3500+ dealers in a bad spot. The problem on the ground is training parts and counter guys to use the system properly and follow the superseded parts chain to the correct part.

 

[jfheath]

Hmm. 43510-MCS-G02 does look like the same thing, but it only shows on 2007 and Police models. Not 2008. Any issues you think on using it on 2008? Very confusing.

Which website are you using for the fiches ?

 

[SKR]

Which website are you using for the fiches ?

I see it in a few places -

https://www.partzilla.com/catalog/honda/motorcycle/2008/st1300-a/rear-brake-master-cylinder-st1300\

Honda Motorcycle 2007 OEM Parts Diagram for Rear Brake Master Cylinder | Partzilla.com

Buy OEM Parts for Honda Motorcycle 2007 Rear Brake Master Cylinder Diagram

www.partzilla.com

2008 Honda ST1300 A REAR BRAKE MASTER CYLINDER (ST1300) | Ron Ayers

Shop online for OEM REAR BRAKE MASTER CYLINDER (ST1300) parts that fit your 2008 Honda ST1300 A, search all our OEM Parts or call at 252-758-3084

www.ronayers.com

2007 Honda ST1300 A REAR BRAKE MASTER CYLINDER (ST1300) | Ron Ayers

Shop online for OEM REAR BRAKE MASTER CYLINDER (ST1300) parts that fit your 2007 Honda ST1300 A, search all our OEM Parts or call at 252-758-3084

www.ronayers.com

Interestingly I don't see it on David Silver - they only have smaller components, not the assembly from my search.

The image below is from Partzilla, conspicuously skipping 2008 and later models except for the Police versions.

 

[dduelin]

Hmm. 43510-MCS-G02 does look like the same thing, but it only shows on 2007 and Police models. Not 2008. Any issues you think on using it on 2008? Very confusing.

Speaking with Igofar a little more, he thinks they're the same part - just different vendor supplying the police bikes hence the different number. The diagrams are identical, though I wouldn't want to trust my life on the diagrams alone.

Indeed the entire assembly 43510-MCS-R01 for 2008 model ST1300s is NLA No Longer Available but the seal or rebuild kit 43520-MCS-G02 is still available. No comment on trying to see if a critical system part can be substituted.

A vendor change or minor revision is noted in the last three characters. The first 5 numeric characters indicate the major part number and the middle three the bike it goes to.

The odd thing thing here is that when a part is changed enough to stop sell of the original and supersede it with the new part the original part is crossed out and the new revision is included in the diagram to show the change and that the newer part replaces the old one. If a old part was hanging around dusty on a shelf and wasn't part of a quarantined recall it could be used in place of the newer revision. A part NLA will show no such chain. It's just not revised and not available anymore.

 

[SKR]

So that G02 part is actually a rebuild kit? That's really weird. It has the same diagram as the full assembly and everything. Well, that answers that I suppose... hope I don't need one!

 

[dduelin]

So that G02 part is actually a rebuild kit? That's really weird. It has the same diagram as the full assembly and everything. Well, that answers that I suppose... hope I don't need one!

Make sure noting 43520 not 43510. xxxxx20 is the rebuild kit and xxxxx10 is the entire assembly
See how the number 5 is pointed to the box that contains the entire master cylinder sub assembly? That is line 5 associated with 43510-MCD-R01.

12 points to a sub assembly within the bigger box 5?

12 is the seal kit, the rebuild kit 43520-MCS-G02.