Rear Tire Dragging

Bmacleod said:
Wow, that is one filthy bike!!! I wouldn't be proceeding any further without first rebuilding that caliper, or at least removing, inspecting and cleaning those pistons before seal damage occurs. I suspect that the rear piston seal may already be damaged and who knows, the pistons could be damaged as well. After cleaning the rear end up, one has to assume the front needs attention as well. Trying to solve a problem with caliper(s) looking like that could have you chasing your tail for quite a while. Honestly, I would question any mechanic that didnt raise alarm bells at the sight of that caliper and not go any further until that was addressed. :twocents1:
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And if you look at one of the pictures he just posted, it looks like a seal is already damaged on one piston, probably by pushing the pistons in before cleaning them, and forcing all the dirt past the seals.
Agreed, the calipers should be completely rebuilt (all) and everything cleaned properly and correctly.
Impatience and wanting to ride will only cause more damage to the bike if it keeps getting ridden like this.
 
Your brake caliper pistons should be bright and shiny (no pits, dings, or corrosion) over their entire cylindrical surface (excepting the end rim). The pistons should be cleaned w/ a shoelace (piece of string) and brake fluid every time you pull the rear wheel or service the brakes. In a normally functioning brake system, the square cross section o-ring in each piston bore distorts slightly when you apply the brakes. Let up on the brakes and this o-ring pulls the pistons back into the bore a few thousadnths of an inch. This dirt will hold moisture and eventually cause corrosion on the surface. If the caliper is disturbed (by manually pushing it which will push the pistons back into their bores) the dirt is forced past the o-rings, possibly damaging them.
 
Old Glory said:
That's exactly the symptom. It's a light drag - the way one used to adjust shoe pads on a car. I was curious since this is a new "feature".

John-
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Just got mine back from the shop after a brake bleed and new pads and same thing. Light drag only with no performance issues.
 
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I would not know that there is anything wrong with my rear brake if I didn't park & take my glove off after riding several miles and feel the brake rotor very quickly after stopping --not giving it a few minutes to cool off (it cools very rapidly.)

Or.... I wouldn't know I had a problem if I didn't try to spin the rear wheel by hand while the bike in neutral up on the center stand.
 
Oblivious to the warning signs of failed safety inspections? Denial? Ostrich?
That’s like saying I wouldn’t know my duty gun was empty unless I removed the magazine and checked it.
Or I didn’t know I had Covid unless I looked at the test results.
Honestly don’t know what else to say, you say the wheel only turns by hand, but because you can put it in gear and roll forward you think it’s ok, and keep riding it, and unless you check it, you don’t know it’s not working correctly!
You have checked it, you saw for yourself that it is dragging, yet you keep trying to convince yourself it’s ok to keep riding it?
Hope you figure this out soon before you end up hurting yourself, or damaging the bike beyond repair
 
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Larry that's just a crazy rant.

Go up and re-read what I wrote again, and what the person above me wrote.

Obviously we are talking about performance issues. "Performance" meaning things you can feel / see on the road. My brake dragging problem is so minor at this point that it does not affect performance : not acceleration, not braking, and not cornering. That's my point-- you have to do some diagnostic tests to find out there's a problem!

YOU YOURSELF advised me to test the bike while I was riding at home by pulling in the clutch while steadily cruising on a level stretch of road to see if I could feel sudden deceleration and when I gave you the answer (no) you said well it doesn't mean anything 'cuz that isn't a valid test. (?!?)
 
Yes, I think it's OK to ride a 5 miles to a mechanic shop and five or 6 miles back and that's what I did the other day.

I told you though, I generally have this bike parked (SINCE SEPTEMBER!) and I am not going out on pleasure rides anymore. I want to -- I want to ride hundreds of miles up in the north Georgia mountains I want to take it to Alabama and South Carolina but I haven't done any rides on this bike since September just a few little putt's here and there to run tests on the thing.

And clearly the only two qualified ST 1300 mechanics in North America are 1800 miles away and 40 miles away respectively, and the guy who's only an hour away from me is too busy to work on this bike possibly until the spring.
 
gunsmoker said:
I would not know that there is anything wrong with my rear brake if I didn't park & take my glove off after riding several miles and feel the brake rotor very quickly after stopping --not giving it a few minutes to cool off (it cools very rapidly.)

Or.... I wouldn't know I had a problem if I didn't try to spin the rear wheel by hand while the bike in neutral up on the center stand.
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Having been there and done that, you could have at least four possible faults causing the drag:
1. Misaligned calliper, I speak from personal experience that it is really easy to cross-thread the main sliding pin and have it sit other than parallel to the other pin. In my case that pulled the rear pad onto the disc as I tightened the sliding pin. I bought a relplacement bracket to fix that one. Sounds like you have already checked this one off.
2. Crud behind the piston seals; this builds up and squishes the seals hard against the piston and stops it retracting away from the disc nicely. You need to pull the calliper apart and clean out each seal groove.
3. The dreaded seized (or clogged) SMC; this stops the outer pair of pistons retracting and is the truly dangerous issue for an unmaintained ST
4. A clogged return port in the footbrake master

One diagnostic steps you can take is to crack one bleed valve at a time and see if that releases the drag. That tells you if there is an issue with line pressure not being released nicely (e.g. 3 or 4). If there's no pressure causing drag then your issue is likely at the calliper only.

After I replaced the calliper seals and swapped out the caliper bracket, I could get about 2 revolutions with a good hard shove of the foot.
 
gunsmoker said:
Larry that's just a crazy rant.

Go up and re-read what I wrote again, and what the person above me wrote.

Obviously we are talking about performance issues. "Performance" meaning things you can feel / see on the road. My brake dragging problem is so minor at this point that it does not affect performance : not acceleration, not braking, and not cornering. That's my point-- you have to do some diagnostic tests to find out there's a problem!

YOU YOURSELF advised me to test the bike while I was riding at home by pulling in the clutch while steadily cruising on a level stretch of road to see if I could feel sudden deceleration and when I gave you the answer (no) you said well it doesn't mean anything 'cuz that isn't a valid test. (?!?)
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Let’s get a few things corrected first shall we…
Not a crazy rant, just worried you’re gonna hurt yourself.
As far as pulling in the clutch, what was explained to you was, yes as your approaching a stop, at a couple miles an hour, pulling in your clutch lever (when your brakes are dragging) will be more noticeable to someone who is in touch with their bike, and knows how things should operate and feel.
Moving a 700 plus pound motorcycle at freeway speeds and expecting to have dragging brakes bring it to a stop just by pulling in the clutch is silly.
Rolling the bike backwards in your garage, when the brakes are dragging is very noticeable, the fact they won’t over power brakes that are dragging on a bike with 100 horse power is foolish.
The way the safety inspections are done, on the stand, checking for wheel rotation are that way for a purpose.
The fact that YOU can’t tell a difference does not make the way you check or test things correct.
The fact you stated several times that your wheel will not continue to rotate after your hand is removed speaks volumes of how bad your brake system is working, whether you agree with that or not.
Trying to think of this as a performance issue is just plain foolish! You say your brake issue is so minor that YOU can’t feel it, yet your wheel won’t turn without manual help, tells me you should have a qualified mechanic, who understands this bike, ride it and get his input, as it sounds like you are not that in tune with your bike, or just want to ignore all the warning signs.
Ask Aniwack if he would feel safe riding your bike in its current condition.
I’m guessing for safety reasons, he would politely decline.
 
I rode a little bit today, locally.

I was prepared for the rear brakes
to heat up, and I made use of this
friction-generated heat.

IMG_4294.jpegIMG_4293.jpeg


That's 1 hot dog +2 marshmallows toasting from the overheating rotor,
and one hotdog bun toasting on the left muffler.
 
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