Rear Brake Lock-up

Jackboy · Jun 23, 2017

Hi,

On Sunday (in 30 degree heat - if relevant) my rear brakes felt as if they were binding a little after a 1 hour break in a 100 mile round trip. I managed to get around 1 mile away and the rears just completely locked up. Managed (with help!) to drag the bike to the side of the road and free them by loosening a bleed nipple and forcing the pads off the disc.

I rode home (only another mile or so) using only the front brake (I'm guessing the rears must have been engaged due to the combined braking system) without issue.

I've read a few threads which point towards the SMC being faulty, but have a couple of questions:

Is it possible this was a one off due to the heat - I also had clutch issues for the last mile?
Should I check anything else first?
Is it a job that can be carried out by a novice using a Haines Manual / this forum as a guide?
Any idea of cost (UK based)?

It's a 2003 1300 ABS with 73k on the clock. I've only had it since January so know little about it's history, although it does have a decent service history record.

Thanks in advance...

Blrfl · Jun 23, 2017

Jackboy said:
Is it possible this was a one off due to the heat - I also had clutch issues for the last mile?

Probably not. 30 may be hot in the UK, but a lot of us on this side of the pond ride in temperatures pushing 40 without hydraulic problems.

Should I check anything else first?

Find out when the last time the hydraulic fluids were changed. If it was any more than two years ago, a full flush and bleed is in order. Old fluid tends to get sludgy, especially in the rear lines.

Also make sure the caliper stopper bolt is in place on the left side of the swingarm. If it isn't, one or both of the rear lines can get pinched when the caliper bracket pivots forward.

All of the calipers on this bike have two chambers and two bleeders. Which one you cracked to take the pressure off the rear will reveal what part of the system is having problems. (Here's a diagram of how the linked brakes work: CLICKY.)

Is it a job that can be carried out by a novice using a Haines Manual / this forum as a guide?

If you can do brakes on a car, you can do the brakes on this bike. There's more to do, but other than having to suspend the front caliper at a certain angle, it's not much different. Follow the instructions to the letter and it's hard to screw up. I would recommend the Honda service manual if you can get your hands on one.

--Mark

Igofar · Jun 23, 2017

On a bike that is 14 years old, with that mileage, and you don't know if the prior owner(s) flushed or bled the brakes often, by guess would be the SMC is suspect.
My guess that your issues with the clutch also were because the brakes were dragging severely and trying to stall the engine etc.
Other things to check would be the condition of the guide pins, clips, and pads.
You also want to check any recalls for the PCV etc.
As you found out, when the rear brake locks up, you can at least move it off the hwy by opening up a bleeder to reduce pressure, however, due to the linked system, the front brake also activates the rear system if you try to ride it home.

Igofar · Jun 23, 2017

Blrfl said:
Probably not. 30 may be hot in the UK, but a lot of us on this side of the pond ride in temperatures pushing 40 without hydraulic problems.

Find out when the last time the hydraulic fluids were changed. If it was any more than two years ago, a full flush and bleed is in order. Old fluid tends to get sludgy, especially in the rear lines.

Also make sure the caliper stopper bolt is in place on the left side of the swingarm. If it isn't, one or both of the rear lines can get pinched when the caliper bracket pivots forward.

All of the calipers on this bike have two chambers and two bleeders. Which one you cracked to take the pressure off the rear will reveal what part of the system is having problems. (Here's a diagram of how the linked brakes work: CLICKY.)

If you can do brakes on a car, you can do the brakes on this bike. There's more to do, but other than having to suspend the front caliper at a certain angle, it's not much different. Follow the instructions to the letter and it's hard to screw up. I would recommend the Honda service manual if you can get your hands on one.

--Mark

Good advice about the stopper bolt! I have had (3) bikes come through the garage this month, that were either missing the stopper bolt, or it was loose and trapped from falling out by the muffler!
I've also talked to at least two members who also have stopper bolt issues, one cutting the rear line causing failure.
:plus1:

SMSW · Jun 23, 2017

Anything is possible. An asteroid could squash you while you are reading this, but it is not very likely. Since the system is linked, squeezing the front brake would have actuated the SMC which should have locked up the rear again.

The condition of the SMC depends on how often the brakes were bled, riding conditions over the life of the bike, etc. This is the first thing that I would check. And yes. A novice can service this though not having seen a Haines Manual I cannot speak to it (the ones for my old cars were pretty good). I'd suggest you get the Honda Shop Manual.

Two other suggestions - go to Forums > community > member map. See if anyone lives near you and you might find someone who can help you. You can click on their name and PM (private message) them.

Sorry to be redundant, I just saw Larry and Mark have responded more quickly than I with the same info.

One other thing. Depending on how long since the last fluid/bleed, you might consider doing the clutch as well. You will be doing this for the brake system as part of your repair. Honda suggests changing brake fluid (and coolant, but that's another thread) every two years.

Jackboy · Jun 23, 2017

Thanks all, hopefully the weather will improve here so that I can have a good look.

I might be back...

POOCH · Jul 19, 2017

It's the piston valve on front left fork leg clean corrosion from piston push rod lubricate, then pull rubber boot back and lubricate every 3 to 4 months you should not have this issue again no need for brake bleeding.

Igofar · Jul 21, 2017

This is called the secondary master cylinder, and I would suggest not trying to pull the rubber boot back for fear of tearing the boot, and you should NOT be spraying any oil or solvent (WD40) like stuff in there, as it could seep past the seal and contaminate the brake fluid etc.

Blrfl · Jul 21, 2017

Igofar said:
... you should NOT be spraying any oil or solvent (WD40) like stuff in there, as it could seep past the seal and contaminate the brake fluid etc.

I'll add to this that anything petroleum-based will not get along with the rubber and will eventually destroy it. That's why they call for silicone grease around anything brake-related that needs lubing.

--Mark

Landfellow · Jul 29, 2017

I am curious as to how the OP has made out. The same thing happened to me last week. I found a 2012 ST1300 with 354 miles on it. The guy had a GW and wanted something lighter. He bought the ST in 2014 but never like it.... so it sat. A year ago he passed on and his wife was selling the bike. All fluids were clear and with a jump. it started right up. I filled the tires to proper pressure and test drove it around the block. Everything worked fine. I thought I had found quite the deal. I trailered it home. Once home put in fresh gas and off I went. A block later the rear tire froze up. As with the OP I cracked open the bleeder and drove it home using only front brake. I did notice even with only front brakes the pressure from the SMC the rear brakes were seized again. The first time I bled the outer nipple, using only the front brakes I bled the front nipple (on the rear caliper). I intend to do a complete brake flush later this week. Any clues? Would it most likely be the SMC, rear caliper, or maybe RMC? I am a little disappointed as I sold my BMW RT thinking I was getting a more dependable bike. I guess every model has its problems. Thanks in advance for any suggestions

Landfellow · Jul 29, 2017

Hi again,
Sorry if I didn't introduce myself. I joined back in February, have always lusted after an ST. Finally found a very low mileage one (see above) I have owned several bikes but never a Honda.
Landfellow

ST Gui · Jul 29, 2017

Landfellow said:
I am a little disappointed as I sold my BMW RT thinking I was getting a more dependable bike.

Before you pass judgement on bike that's been sitting without any care for a protracted time read through some of these threads and be patientâ€” someone will get you sorted.

You've yet to realize it but you got a great bike. It just needs a little massage. Though the ST does have a quirk or two it's very short on 'problems'.

Part of that massage should be bleeding the front and rear brakes and clutch.

SMSW · Jul 29, 2017

Landfellow said:
I joined back in February, have always lusted after an ST.
Landfellow

I suggest you pick up a Honda Service manual for your bike. This book is indispensable. There is a procedure for bleeding the brakes correctly - and while there are posts and 'how to do it' articles on this website, there are other service procedures not as well described.

Landfellow · Jul 29, 2017

I already ordered a manual and plan on doing the required service. I am not passing judgement on the bike. It was just ironic. I have had several Beemers serviced them religiously and never had a problem. But when on a trip in the back of my mind I always worried about a final drive, fuel pump, controller etc or something that wouls leave me stranded with dealers being far and few between. I figured the worst thing that could happen with the ST would be a stuck thermostat and that wouldn't have left me stranded. Anyway, I love the ST. Even though it was a short test ride I felt it was well balanced, had lots of power and was the perfect riding position. I am just eager to get to the bottom of the problem so I can get out there and put some miles on it. I have a feeling it will go to the front of the herd, :>)

Igofar · Aug 3, 2017

Hold my beer, I got this :rofl1:

When we figure out what the problem is, Mr. Landfellow will report back here and let everyone know what we found, and how it was corrected...
....keep moving folks.....nothing to see here......work in progress.....
There will be a brief wait before the next response, as we are waiting for tools and some other stuff. Will keep you updated when it happens, as it happens....
Igofar

POOCH · Aug 10, 2017

THAT IS WHAT IS HAPPENING TO THE SMC WATER SEPAGE THROUTH THE OUTER SEAL, IT CAN BE PULLED BACK ENOUGH TO LUBE THE VALVE, THE PROBLE THAT HONDA MADE IS THAT THE VALVE PISTON FACES UP WITH A SEAL TO KEEP OUT DIRT AND WATER, SORRY BUT THIS DESIGN IS WEAK IN THE LONG RUN I ALSO HAVE A 2000 HONDA BLACKBIRD WITH THE SAME BASIC SETUP LINK BRAKE SYSTEM THE DIFFRERNCE IS THAT THE PISTON FACES DOWNWARDS WITH A SEAL AT THE BOTTOM NO CHANCE OF ANYTHING BEING ABLE TO PENATRATE BECAUSE OF IT'S POSITION IT HAS NEVER, NEVER, NEVER HAD THIS ISSUE.

jfheath · Aug 10, 2017

Igofar said:
Hold my beer, I got this

............
There will be a brief wait before the next response, as we are waiting for tools and some other stuff. Will keep you updated when it happens, as it happens....

In the meantime, I'll be drinking your beer. :beer8:

Igofar · Aug 10, 2017

I'll always have a cold one in the fridge for you John :capwin:

Big Buzz · Sep 5, 2018

Jackboy said:
Hi,

On Sunday (in 30 degree heat - if relevant) my rear brakes felt as if they were binding a little after a 1 hour break in a 100 mile round trip. I managed to get around 1 mile away and the rears just completely locked up. Managed (with help!) to drag the bike to the side of the road and free them by loosening a bleed nipple and forcing the pads off the disc.

I rode home (only another mile or so) using only the front brake (I'm guessing the rears must have been engaged due to the combined braking system) without issue.

I've read a few threads which point towards the SMC being faulty, but have a couple of questions:

Is it possible this was a one off due to the heat - I also had clutch issues for the last mile?

Should I check anything else first?

Is it a job that can be carried out by a novice using a Haines Manual / this forum as a guide?

Any idea of cost (UK based)?

It's a 2003 1300 ABS with 73k on the clock. I've only had it since January so know little about it's history, although it does have a decent service history record.

Thanks in advance

Hi

I have recently had this exact same issue and the bike has been off the road for some 6 weeks mainly waiting for parts which are all special order in the uk. Its related without doubt to the secondary master cylinder (smc) on the left front fork on the st1300. The piston compresses when the front forks move through breaking so its not actually linked to the front brake fluid system at all.
My back brakes cooked metal on metal on metal as I was on a group ride and could not get off and it did not feel that bad. When I did stop to look at the issue the thing was smoking and nothing was left of 3 weeks old rear brake pads. I now know putting water on something so hot is not a good idea but I thought it was going to set on fire, the rear ~rubber hose went bang and I had normal front brakes to get home. The smc part number was superseded, I have been told, in 2008 and all earlier models have a potential issue with the smc and rear brake binding or locking up. The ports inside have now been made bigger and a new part number issued for all post 2008 models which should have the later and modified smc. Obviously Honda are not going to advertise this issue and take any ownership but a winter swap of the smc will prevent this ever happening to you. If the pipe had not gone bang and it freed up the rear end I would of been stranded an hour from home on my daughters 21st birthday afternoon tea party and been forever in the dog house!
The rear brake lines have been changed along with drive shaft bearings and head stock bearings, which all needed doing along with a brand new smc, a reasonable £800 bill followed and the bike runs like a dream. There is no rear brake binding at all and iv tested it several times, this was a constant issue before whenever the thing got hot or on a long run. A few times I have had rear end binding noises on motorway services and the like and I have had the wheel bearings checked by other mechanics who like me had no clue what this issue was. Im told it can also be linked to air in the system and there is a good write up on the forum about taking off the smc to tilt and get the air out when bleeding rear lines .. any air or moisture will obviously affect the brake fluid expansion nature and potentially cause an issue with rear brake bind. It could also of been the start of the issue with the smc so if you have a binding issue best to change a pre 2008 smc to the new one and replace the fluid ensuring no air is trapped by using a vacuum pump as mentioned in this thread.
I am not that mechanically minded, more a rider than a fixer, but I am very pleased to say that my bike now runs better than ever and I am very grateful to Simon at Chase Superbikes Centre near Cannock UK - a rare breed of professional bike mechanic who really knows his stuff.

With rear brake lock up linked to this issue just slacken off the rear brake nipple and you can ride with normal front brakes .. dont apply water and stop as soon as possible - advice I could of done with when it happened to me! A new smc, flush and new fluid correctly bled would be a worthwhile investment to any rider of pre 2008 st1300, especially if you are experiencing any rear brake binding.

re Honda ST1300 2004 70k non-abs

Mark Burrows
Pan Clan Member

Mophead · Sep 6, 2018

I know this will generate some "How stupid can you be?" but why not just remove the secondary master cylinder and plug off the proportional control valve and its associated connections?
For that matter why not remove the modulators (if I even have them) and just run the front calipers off the front master cylinder and run the rear brakes off the rear master cylinder. Pretty sure that would eliminate all the rear wheel lockup scenarios.
My bike is Non ABS so thinking that would solve a lot of ills. Braking the old fashioned way like most of us learned.

OK, let me have it.

Rear Brake Lock-up

Jackboy

Blrfl

Natural Rider Enhancement

Igofar

Igofar

SMSW

Jackboy

POOCH

Igofar

Blrfl

Natural Rider Enhancement

Landfellow

Landfellow

ST Gui

240Robert

SMSW

Landfellow

Igofar

POOCH

jfheath

John Heath

Igofar

Big Buzz

Mophead