Secondary Master Cylinder Information

[Igofar]

This week I've replaced 7 secondary master cylinders that were all completely frozen solid!
3 were police motors, with 60,000 to 80,000 miles, and the other 4 were civilian models with very low mileage 20,000 or less.
So today, between calls, I spent the day cleaning them, and taking them apart for inspection.
4 of them had the piston frozen/rusted at the beginning of the bore, 1 was out of the bore a bit, and 2 of them were jammed half way down the bore.
The last two stranded motor officers in the middle of an intersection and were unable to be moved.
In the model years 2003 - 2007 the spring(s) behind the plunger measured 22 mm, 25 mm, 28 mm, and 30 mm (these were the old style units with the spring trapped on the plunger).
In the model years 2009 - 2012 (the new style longer/narrower spring with the hockey puck on the spring ) were found 32 mm, 35 mm, and 40 mm in length.
Seems that whenever these things start dying, binding, and starting to stick in the bore, also causes the springs to take a set where ever they get stuck, and then remain there.
Just one more thing to think about when your brakes start binding.

 

[caldercay]

model years 2003 - 2007

model years 2009 - 2012

What about 2008?

 

[Igofar]

My point was the bikes I worked on, and every single smc spring had taken a set at a different length, weakening spring rates probably contributed to the smc unit failing etc.

 

[caldercay]

My point

Understood.

However, you listed bike models thru 2007 as having one design ... then listed bikes from 2009 on as having a newer design... but how about the 2008 model? Does it fall into the older design or newer? Or have we not seen a 2008 SMC to know?

 

[sirbike]

Understood.

However, you listed bike models thru 2007 as having one design ... then listed bikes from 2009 on as having a newer design... but how about the 2008 model? Does it fall into the older design or newer? Or have we not seen a 2008 SMC to know?

2008 is the newer design.

 

[Igofar]

Understood.

However, you listed bike models thru 2007 as having one design ... then listed bikes from 2009 on as having a newer design... but how about the 2008 model? Does it fall into the older design or newer? Or have we not seen a 2008 SMC to know?

I listed just the model years that I worked on this week, and pointed out that a couple of them were the later model design in case someone wondered why a couple of them had longer springs.
The 2008 year model(s) that I've opened up have had both styles of SMC plungers/springs. This was the first year that they started making the changes, and it probably depends on what month the bikes were put together if they got the left over parts, or the newer parts.
Hope this answers your question.

 

[OkieRider]

It seems noteworthy the police units probably got regular maintenance and thereby lasted longer than the private ownership models. Flush those puppies!

 

[Igofar]

It seems noteworthy the police units probably got regular maintenance and thereby lasted longer than the private ownership models. Flush those puppies!

Despite what most folks think, police motors are generally more neglected than other models.
Folks think that the departments have their own motor pool service tech's, and they do for the most part, but the problem is they are automobile mechanics and know nothing about the bikes, with the exception of the older Harley's. Or folks are told by the auction person selling the bike(s) they were always maintained by the local Honda shop....not always the case either.
Or my favorite....It was never put into service/duty/patrol, thinking maybe it was the captain's bike, or a probation officers bike, or a parade bike, funeral or escort bike, etc.
When truth be told, several were TRAINING bikes....crash test dummies come to mind. Hard life for sure.
But as OkieRider said, Flush those puppies at least yearly!

 

[triospec]

In the model years 2003 - 2007 the spring(s) behind the plunger measured 22 mm, 25 mm, 28 mm, and 30 mm (these were the old style units with the spring trapped on the plunger)

Larry,
FYI datapoint: the plunger spring on the SMC (2007) I just replaced measures 31.3 mm.

 

[shadowknows977]

So you the new guy here, what sort of preventive maintenance are we talking about for the SMC? Just flushing the brake lines and spraying some wd-40 on the outside to wipe it down...or something more involved like disassembly and deep cleaning?
Thanks

 

[shadowknows977]

Sorry I'm the new guy here and typing with a phone key board

 

[OkieRider]

So you the new guy here, what sort of preventive maintenance are we talking about for the SMC? Just flushing the brake lines and spraying some wd-40 on the outside to wipe it down...or something more involved like disassembly and deep cleaning?
Thanks

Bleeding the brakes is somewhat more involved with the linked system. You have to remove side plastic and execute multiple steps in a specific sequence and you may not abbreviate it in any way.

 

[ojm]

Hi All.
New owner from Denmark joining in!
I got a 2005 model, 72000 km/45000miles.
If I update the SMC, do I have to do all the 7 steps in the bleeding "manual" or just the steps on the front left caliper?
I hope You "get" my english!

Ole Mathiasen - Denmark,

 

[Igofar]

Hi All.
New owner from Denmark joining in!
I got a 2005 model, 72000 km/45000miles.
If I update the SMC, do I have to do all the 7 steps in the bleeding "manual" or just the steps on the front left caliper?
I hope You "get" my english!

Ole Mathiasen - Denmark,

If by update, you mean replace the entire unit (strongly recommended over trying to rebuild one), then yes, you must follow the correct and complete bleeding procedure (7) bleeders, in the correct order.
Before you try and take this on, you should check out the Article section on Avoiding the pitfalls, and several other pieces on SMC replacement/bleeding.
Oh and by the way, Welcome to the forum from sunny Arizona!
Igofar

 

[ST11Nut]

Avoiding the pitfalls thread here: https://www.st-owners.com/forums/threads/st1300-maintenance-brakes-avoiding-the-pitfalls.135125/

 

[jfheath]

This may help to understand where fluid comes from and goes to as well:

Article [13] - ST1300 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...

www.st-owners.com

 

[ojm]

Thank You everyone.
I have been reading all the articles on brakes ,and have changed the brakefluid doing all the 7 steps.
But the rear is draging a little to much.
Igofar,thanks for the welkom greeting, recommende a total new one, rather than repair, but where to bay one??

Ole Mathiasen-Denmark.

 

[jfheath]

Igofar,thanks for the welkom greeting, recommende a total new one, rather than repair, but where to bay one??

I'll answer that for @ojm Larry - since he is in Europe

Oh, Welcome @ojm. I missed that it was only your 2nd post.
There are a few good places in Europe. This is one that I have used in the past.

Genuine Honda Parts & Spares - UK & Europe's #1 | MSP

Shop Honda parts and spares from Europe's largest spare parts provider. Fast and safe delivery worldwide from reliable couriers.

www.motorcyclespareparts.eu

Please note - you list your bike as a 2005 model, but check the white label on the frame under the seat - my guess is that it will indicate a 2004 model. In which case it will state ST1300 4 or ST1300A-4 (the letter 'A' indicates whether it has ABS or not). If the label says '4' or 'A4' you need to give 2004 as your bike's year.

The website doesn't list a 2005 model, and I know that there was not a 2005 model in the UK. It might have been built in 2005, but using the 2004 specs. All models up to 2006 use the same L Brake caliper.

You need the complete part - labelled on this diagram as #2 - I've highlighted the outlined bit - it comes pre-assembled. Check the diagram for the details that you enter onto the website.



You will find it under the section 'L Front Brake Caliper' after you have entered the Brand, Type, Year, Model.

 

[SMSW]

I'm not sure if those articles give you all the shortcuts. Larry has posted elsewhere that there is no need to remove the fairing. Bleeding at the calipers is straightforward, To reach the proportioning valve, @Igofar lifts the tank and props it up. He then pulls the right middle cowl (probably has to remove one screw or two holding it to the frame) outward a bit at the top and the p-valve is right there at the top of the plastic. I always pull the fairing because I bleed the brakes during annual down time due to snow in winter.

 

[ojm]

Thanks again.
Thats all good stof to know.
What SMSW and Igofar tells about tank/ fairing is "gold"
I`ll look into the UK shops.

Ole Mathiasen-Denmark.