Help Me Stop My Brakes From Stopping

Joined
May 20, 2016
Messages
12
Location
Kentucky
Bike
'07 ST1300
Having read much about the issues of brake dragging / locking after it happened to me unexpectedly and alarmingly I see that most of the time the SMC is the culprit. I would like the opinion of the pros here on this forum as I know it supersedes my Honda dealership. I'm not being critical of them just complimentary to the knowledge and experience of this forum.
To my point: when I use the foot pedal after a while the rear (I think) drags or locks. Pressing it several times will release it, at least for now. I carefully don't use it and won't till the problem is fixed. Using the hand lever I have no dragging or lockup: works fine.
My question: If the SMC were the problem wouldn't both the hand and foot levers both cause this effect? I'm thinking that in this case this points to the rear brake master cylinder or caliper assembly or something else confined to the rear only.
I yield to the experienced ones here for more insight; any input is greatly appreciated.
When I went to the Honda dealership for assistance their remedy was to change the brake fluid and see what happens. I plan on doing that (have <12k miles) but before that process I would like to fix the appropriate issue so I'm doing the fluid change after the probable fault is fixed.
Unrelated but nonsensical to me: the dealer said it would be about 2 weeks before the bike could be looked at; I'm OK with that- we all wait our turn. I asked if they could call me a day or two before needing the bike. Was told "NO" you have to leave it and we will get to it in the order brought in. As an avid rider I'm not willing to sacrifice Summer riding for 2-3 weeks and this makes no sense to me. We all make appointments - what gives?? Anybody have input on this?
 
Joined
Aug 9, 2010
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292
Location
Vernon BC Canada
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09 ST1300
Since you say it does not stay dragging or lock when the front lever only is used, one would tend to rule out the smc. I would look for a sticking piston or caliper slide in the rear. To rule out the cause of sticking I would crack the bleeders one at a time on the caliper when the brake is dragging/locked, and if it immediately frees up thenthe problem is not likely rear caliper, problem is elsewhere.
 

T_C

Joined
Mar 8, 2012
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4,341
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St. Louis, MO
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2005 St1300
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8568
Anybody have input on this?
1) Find a new service department, after you let the old one know why.
2) Do your own maintenance.

Between this foruma nd the service manuals, not much the average home person can't do.
 
Joined
Nov 10, 2007
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61
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Vancouver, British Columbia, Canada
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1&2 2005 ST1300ABS's
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8562
The way your describing this problem, I would tend to think it is the rear master cylinder.

What I would do is do what Honda recommended first. Bleed the front and rear brake system. Also while you have the SMC off, lube the needle bearings where it pivots. Then do a test run and report back.
You may just have a boat load of air in your rear braking system and it may not be allowing you calipers to retract.
Also, head over the the articles section.
You will find brake bleeding articles, videos on how to bleed your brake system and also an article to clean your brake pistons.
Best of luck trying to troubleshoot you problem.
 

ST Gui

240Robert
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SF-Oakland CA
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ST1300, 2010
jjtdmd said:
issues of brake dragging / locking after it happened to me unexpectedly and alarmingly... I carefully don't use it and won't till the problem is fixed... As an avid rider I'm not willing to sacrifice Summer riding for 2-3 weeks
I'm assuming that this is no longer as unexpected and alarming issue as before. Muscle memory is often a difficult thing to consistently override with unintended consequences. Can you feel the onset should you slip up? I think there's been one mention here about rotor and caliper damage due to riding with the rear brake dragging.


Al Gully said:
Bleed the front and rear brake system. Also while you have the SMC off, lube the needle bearings where it pivots. Then do a test run and report back.
Have you bled the ST's brakes before? It's worth a try and fluid is cheap. It's a little involved until you know how because of the linked brake system and not done thoroughly it's not hard to leave air in the system. Removing and tilting the SMC is part of that.

It sucks that you got a NO response instead of a reasoned explanation. Sometimes a mechanic is able to move ahead when one or more jobs stall for whatever reason but keeping your bike for two weeks when the assumption is they won't be able to touch it seems unreasonable. If you've got the place tools and time doing everything you can is a good investment.
 
Joined
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Medina, Tennessee
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2021 Tracer 9GT
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375
Sounds like the rear master cylinder or caliper, hopefully it is the caliper.
First step is remove the rear wheel, take the caliper off the axle, take the pads out of the caliper, pull it apart so the slide pins are exposed and assess the amount of crud on the pistons. Place a shim in the caliper and gently extend the pistons outward just a little so the crud line is just past the seals. Get some strong household cleaner (409, Fantastic, etc.) and scrub the pistons with an old tooth brush, whatever and get that crud off. Rinse, dry with compressed air. Then push the pistons back in as far as they will go, lube the slide pins with brake grease, put the halves back together, replace the pads, and put everything back together. if you are lucky, this will fix your problem. You might as well do the front too, while you are at it. When I lived in Florida, this was a constant problem that needed to be addressed almost annually.

If this does not work, you probably have some crud in the rear master cylinder blocking the bleed back orifice. The only way to fix that is to remove the assembly, take it apart, clean thoroughly with emphasis on the orifice. Put back together with new crush washers. Then you must bleed the entire system. This is not a fun job.

About once a year I carefully squirt a little silicone grease inside the piston boot of the SMC. The original is going strong after almost 14 years.
 
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OP
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Joined
May 20, 2016
Messages
12
Location
Kentucky
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'07 ST1300
Many thanks for the replies. Although having only done but small jobs on motorcycles I feel I can tackle the front brake remediation but the back worries me. The thought of removing the back wheel is frightening and I not only don't have the experience but probably lack the tools as well. Is this the only way to repair rear brake problems ? Can they be bled without removing the wheel? Bleeding the system sounded reasonable (actually all comments did) and something I can do.
I just came in from a short ride and applied the foot brake and it stuck slightly; it is definitely the rear wheel dragging and definitely from the pedal. If I were to replace the fluid this would accomplish 2 things - bleeding the system and correcting old fluid. Perhaps this is a good first start but it brings up another question- if I were to work on a caliper/ piston assembly later does this mean that all brake fluid is drained or just some?
 
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375
If you work on the caliper, as I described, the system would remain closed and no fluid would escape. If you remove the rear master cylinder, yes, air would be introduced and bleeding would be necessary. On a ST1300 bleeding is a little more involved than a regular bike due to the linked brakes. It must be done correctly and in proper sequence.
If you lack the skills and tools to remove the rear wheel, I suggest that you seek help from someone close who is more experienced with this sort of thing that has the correct tools.
 
OP
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Joined
May 20, 2016
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Kentucky
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'07 ST1300
You are correct! That is a fabulous article. I have the manual (just purchased) but his explanation makes the manual seem crude. And as a matter of opinion I wouldn't trust my ability to do much if I just relied on the manual. To me it is a reference but in no way prepared me to tackle this job. But this expose' is magical; it makes the job for a novice like me something I feel I can do. Thanks for everyone's input. I'll report on what it turns out to be (assuming that I know).
 
Joined
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2021 Tracer 9GT
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375
Bleeding, as described in the aforementioned link, will result in new, clean fluid being in your system, with no air, which is a good thing. However, I am of the opinion that your issue is either mechanical caused by corroded pistons in the rear caliper or hydraulic lock, caused by a blockage in the rear master cylinder or possibly the SMC.
 
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Sep 18, 2005
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Houston, Tx
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2003 ST1300
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5952
You are correct! That is a fabulous article. I have the manual (just purchased) but his explanation makes the manual seem crude. And as a matter of opinion I wouldn't trust my ability to do much if I just relied on the manual. To me it is a reference but in no way prepared me to tackle this job. But this expose' is magical; it makes the job for a novice like me something I feel I can do. Thanks for everyone's input. I'll report on what it turns out to be (assuming that I know).
You can leave out step 1 and 2 for now, as it is for the front hydraulic circuit (fluid from the front reservoir), completely separate from the rear.

....I would crack the bleeders one at a time on the [rear] caliper when the brake is dragging/locked, and if it immediately frees up then the problem is not likely rear caliper, problem is elsewhere.
Starting your troubleshooting with this recommendation would be a good way to zoom onto the cause of your issue. And it is easy enough to do.
 
OP
OP
Joined
May 20, 2016
Messages
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Kentucky
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'07 ST1300
Well it was an arduous process but I finished it. Changed / Bled the brake fluid and the clutch fluid. It is such a job to take off all the plastic that I had to change the clutch at the same time. Needed to do it anyway since the fluid was 9 yrs old. Fluids were brown but the brake fluid was not gunky whereas the clutch fluid in the reservoir had a lot of gunk in it. Bleeding the clutch was a breeze compared to the brakes; first time as always took an eternity and I made mistakes but will be better from now on.
My most difficult moment was trying to get the tubing on the Right Front-(TOP) bleed screw. No **** room; it would have been nice to have even 1/2 " more. Never heard of any mention of this in reading all the posts- am I the only one to notice this?? The tubing kept coming off because it was in such a tight radius. Are there right angle boots that can be used for this work around?
Actually enjoyed the process as I felt I was doing something constructive and informative. Took it for a mini ride and didn't notice any issues with the rear brake. Will see how it goes; noticing I'm not alone with this phenomenon it would seem that a regular fluid change is mandatory. Have had this bike for 3 months now and get good vibes every time I put the leg over.
I would like to thank all for the advice and especially STTraveler for walking me through the pitfalls and special suggestions; what a helpful, knowledgeable, and friendly person. No way I could have looked at the manual and accomplished this.
 
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I've found that silicone surgical tubing to bleed with (or buy it from SpeedBleeders). Stays on the nipples. Speed Bleeders aren't a bad idea either.

One other possibility of sticking is the rear brake pedal pivot..... might need a clean and lube.
 
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OP
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Kentucky
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'07 ST1300
Well I'm back with the same problem again; brake is sticking again. When I pulled into my driveway I put it on the center stand and can only slightly move the rear wheel. This time it seems that either the pedal or lever causes it to stick although it seems the pedal more likely. The following post from before has me confused; can someone explain this mechanism please. I would have thought that if I cracked the one of the rear bleeders and the rear wheel is released it would be the from the rear system (caliper or master cylinder) and if from the other rear bleeder it would indicate an SMC problem. I can't remember which bleeder affects SMC or rear caliper but...... Please straighten me out on this.

"To rule out the cause of sticking I would crack the bleeders one at a time on the caliper when the brake is dragging/locked, and if it immediately frees up then the problem is not likely rear caliper, problem is elsewhere."

I just opened several bleeders and nothing changed with respect to the rear wheel until I cracked the outside (back) rear bleeder and pressure was released and the rear wheel spins freely. So what is the diagnosis? Corrections? Thanks.
 
OP
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Thanks John for the excellent explanation and Anna's Dad's drawings. I think once again the SMC is the culprit and it follows logically from the rear outer bleed valve releasing pressure. I needed to hear it from someone else to have some confidence as the post I quoted seemed to say the opposite. And it irritates me when I don't or can't understand something.
Also Anna's Dad explained another confusing thing about the SMC which had bugged me- the fact that it had a line going to it from the pedal. Never could understand this until AD explained it. This braking system is pretty complicated. Have to wonder the performance difference if it were not linked vs the linked system. When it works I think it is pretty darned good.
 

ST Gui

240Robert
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jjtdmd said:
When it works...
Which is almost always when properly maintained. Yes it's a somewhat complicated system but worth the effort to stay on top of it.
 
Joined
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Well I'm back with the same problem again; brake is sticking again. When I pulled into my driveway I put it on the center stand and can only slightly move the rear wheel. This time it seems that either the pedal or lever causes it to stick although it seems the pedal more likely. The following post from before has me confused; can someone explain this mechanism please. I would have thought that if I cracked the one of the rear bleeders and the rear wheel is released it would be the from the rear system (caliper or master cylinder) and if from the other rear bleeder it would indicate an SMC problem. I can't remember which bleeder affects SMC or rear caliper but...... Please straighten me out on this.

"To rule out the cause of sticking I would crack the bleeders one at a time on the caliper when the brake is dragging/locked, and if it immediately frees up then the problem is not likely rear caliper, problem is elsewhere."

I just opened several bleeders and nothing changed with respect to the rear wheel until I cracked the outside (back) rear bleeder and pressure was released and the rear wheel spins freely. So what is the diagnosis? Corrections? Thanks.
Man...do I feel your pain...I've got an '08, and started having the same problem back in March. Did all you've done, even replaced rear master cylinder...same thing. Took it to Honda, took them 3 months to figure out it was secondary slave cylinder on the front. They thought it was in the ABS and did something to it causing my ABS warning light to continue to flash. Pitiful....my brakes work right now, I guess I do not have ABS though. Check my fuses a while ago, all are good...does anyone have advice on my next step. Thanks...at least I'm riding again.
 
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