Rear brake failure (linked to SMC)

Here's what happened. I was on my way home a few weeks ago and had to stop a little quicker than usual on the freeway due to stopped traffic ahead. Upon resuming travel, the rear brake started to drag heavily. At this point I tried the usual pumping of pedal and throttle blip to release SMC and limp back home( 4 miles ahead). But the seizure although not complete lockup would never go away. When I was within a 2 miles of home, the rear pedal went completely soft. I was wondering what caused this? When I went home, I found no leaking fluid and the rear cylinder was full. The next morning the brake pedal firmed up. Did I do some permanent damage? Is there anything else I should look for?

Also when I opened up the SMC, the piston was completely stuck in the cylinder, so much so that I had to order the entire cylinder assembly than just the pistons and spring. Hopefully, I can get the bleeding done this weekend and get back on the saddle.
--Ram

Just check the pads and the rotor for heat damage... you may have to scuff up the pads if glazed.

As a sidenote ... if you have a lock up due to the smc, sometimes if you crack the bleeder the pressure will be released at least for a short while to creep home

Sounds to me like you boiled the rear brake fluid. I've done it many times racing. I agree check for heat damage and flush it.

I had my rear brake lock on during a recent trip. I was following another ST. Approaching a corner I tapped my rear brake prior to the corner when my rear brake locked on. I held the bike straight for a while before the back started to drift. Then the back suddenly gripped the road and I was thrown top side. I am lucky to be able to comment on the thread. What recourse is there for this problem with the brakes as it seems to be an ongoing one for a number of drivers?

Not sure if you have any recourse to Honda or not, may want to check with an attorney.

I'm curious as to how many SMC's have failed on these bikes and how many of those owners went to "check with an attorney". I don't see how this comment is relevant here, I don't see any mention of anyone being injured or even crashing. I'm on SMC number 3 since 2007, yes it's annoying but if it really annoys me I'll take the bus and not worry about vehicles with mechanical issues. Maybe a class action lawsuit is in order here? Thoughts anyone?

I may be reading the thread wrong but I would think being thrown topside indicated that he hisided and crashed.

wes_van said:

I'm curious as to how many SMC's have failed on these bikes and how many of those owners went to "check with an attorney". I don't see how this comment is relevant here, I don't see any mention of anyone being injured or even crashing. I'm on SMC number 3 since 2007, yes it's annoying but if it really annoys me I'll take the bus and not worry about vehicles with mechanical issues. Maybe a class action lawsuit is in order here? Thoughts anyone?

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You say checking with an attorney is not relevant then you propose a class action lawsuit...

I can't recall if I've ever heard of anyone crashing due to an SMC failure. This may be the first. In 2008 Honda did redesign the front brake calipers, larger pads and caliper and also a more generous drainage slot vs the hold the pre-2008 bikes had. However, I believe there have still been some failures on 2008 and newer bikes.

I have never liked how Honda did the linked brakes on the ST but it's very similar to how they did them for the Wing. I think those in coastal or colder climates may experience these issues more, those in the UK for instance deal with some pretty crazy corrosive affects and the SMC seems to be weak in that regard.

There's some general comments in the maint schedule about checking for brake operation but I don't remember if there's a specific procedure for the smc, many here will put the bike on the centerstand and spin the rear wheel then push up on the smc to ensure it 1) stops the rear wheel and 2) releases to allow the rear wheel to spin freely.

Has this been reported to the Consumer Products Safety Commission? Might be a better way to get the word out than a class action suit.

Len

CPSC doesn't do cars. That's NHTSA's department.

--Mark

Yes I was thrown hi side and tumbled down the pavement and the bike tumbled after me. The brakes had been serviced about 1250 miles prior to the accident and had been operating normally. We had just finished about 500 miles the day before. Both sides of the bike are damaged, and from pavement markings and how the bike finished on the road I would say it went over twice. I was ahead of the bike and it slide into my backside and pushed me down the road.

Hello there,
'09 ST1300A with 96000 Km
Here is my story - very poor braking especially the rear

Went for a ride - operated the front brake only - then coasted to a stop - rear rotor warmish - looks like SMC is working

Took off again and operated front brake only
Next operated the rear brake (with the front actuated) - again minimal braking
Next release front brake (with rear operated) and the rear brake pedal dropped about 1/2 inch

When done in reverse - operate rear first then front and release front - no issue

Does this sound like air in the system??

Any ideas??
Thanks in advance
Hugh

Yes, purchase a motion pro brake bleeding tool, and service manual and flush and bleed the entire system correctly, search the forum for SMC service work, needle bearings, grease, etc.

I have some thoughts as to the whole SMC issue, which appears to cause more trouble on the 1300 than the 1100....

Personally I would never simply change a set of pads, this means that you build up more and more crud in the caliper and around the pistons, worse still you are pushing dirty and possibly surface corroded pistons back in to the caliper.... this can only lead to trouble.
Every dealer I know, if asked to check the brakes and fit new pads if required, will simply fit new pads.... no cleaning of pistons or caliper....

Every time I change a tyre or service the bike, I clean the calipers.... I used ACF50 to do this as it cleans and protects the metalwork and prevents any further corrosion damage to the pistons...

If doing this I also check the SMC, the bearings, pivots etc.....

I have also now decided, after years of re-using bolts, that I am uncomfortable with this since having two caliper bolts drop out of the right hand caliper on my PC800, despite having been torqued correctly, although I didn't use any threadlock on the bolts.
This has never happened before in all the years I have been doing my own maintenance.....

When servicing my "new to me" NT700V Deauville in April, I was going to re-use the caliper bolts with thread lock applied, but when torquing them up, they felt all wrong.... there was a distinct feeling that they were stretching... so I stopped and used a short ratchet and socket to finish the job.... and ordered new bolts straight away.
New bolts come with threadlock pre-applied and they felt quite different when tightening....

My personal take is that if you don't do your own servicing, you should consider taking classes or attending STOC events where technically competent members demonstrate how to do your own work... this may take more than one or two visits to learn enough to do things like brakes, but it is worth learning.

If you still don't feel up to it, maybe asking the dealer to ensure that the exact work you want done IS DONE.... this is not easy.

Brakes are vital to survival on a motorcycle and although apparently complex, they are not.... they can be if you are not mechanically or technically orientated, but help is never far away.

Never assume that because a dealer says they have serviced your brakes that they mean they are cleaned and inspected, what they mean, usually, is they have checked your pads and replaced as required... this is NOT servicing.

Okay so, a bit of a rant, not trying to stand on toes... the brakes on an ST are good, considering the weight they are expected to haul down from speed.... and if there is anything not working correctly, then there may be trouble ahead.... and you won't stop in time.....

It is even more vital on an ABS equipped bike to ensure the brakes are correctly maintained and this is not just about changing pads.

I have never had any issues with brakes on any of my bikes, other than the bolts on the PC800, which was a one off and I got off lightly.... proper maintenance and cleaning is vital and I highly recommend proper attention to them every time you change a tyre or do a service.
This may mean if you go to dealer, then a chat with your dealer service manager, preferably the actual technician that will do the work, is vital to understand exactly what they are intending to do to your brakes if they require work.

Well that's my 2 whatever currency you deal in.....!

I my case I had a lock up resulting in a crash and injury. Later tear down didn't show any issues with the SMC. It moved fine through its full range and bore and piston showed no sign of corrosion. I never did find any cause of the original crash which is kind or more troubling than running into a know problem

Since the issue the bike has been working fine but it is hard not thinking about the crash every time I drive it.

v4guy said:

I my case I had a lock up resulting in a crash and injury. Later tear down didn't show any issues with the SMC. It moved fine through its full range and bore and piston showed no sign of corrosion. I never did find any cause of the original crash which is kind or more troubling than running into a know problem

Since the issue the bike has been working fine but it is hard not thinking about the crash every time I drive it.

Click to expand...

Wow & you're just around the corner from Rob in Ayr (post #12). Didn't go to the same dealer did you? You guys should compare notes.

So hi again
Did a complete bleed job (vacuum assist and tilted SMC) and removed copious amounts of air mostly from PCV
Braking now much better - at least I can live with it
Thanks for all the info provided
ps - I was able to get access to the PCV buy removing minimal plastic and stretching the rest and having assistance really helps

Oh yeah I forgot - I lifted the tank for access to the PCV

Nice to find and repair the problem yourself.

Firstpeke said:

It is even more vital on an ABS equipped bike to ensure the brakes are correctly maintained and this is not just about changing pads.

Click to expand...

ABS assisted brakes are more critical for those riders than bikes without ABS modulators?
I don't have ABS but I find my brake system to be very critical to the safe operation of my bike.

mcstick_123 said:

Oh yeah I forgot - I lifted the tank for access to the PCV

Click to expand...

Hmm... the PCV sits on the outside of the frame.. curious why did you lift the tank? You can access it from hjust removing a few screws and prying the plastic side panel back a bit. I usually just remove the whole side panel since I'm probably doing some other work anyway.

But pulling all the plastic off the bike does not require lifting the tank. The reason I point this out is that every time you lift the tank you flex the three hoses that are under it. The main hose that joins the upper and lower tank is very short and while flexible, not really something you want to be extreme flexing more than necessary.