Nova-Scotians...

[The Dark Shadow]

Okay, quick follow up question...

Garrie Cook did a fine job of bleeding my full brake system. The SMC seems to be working perfectly, and the brakes truly seem to work better than before. I'm guessing because of the refreshed brake fluid. (I don't know how old the fluid was when I got the bike.)

The back wheel seems to grab less, but still seems to grab more than it should. Why do I say this...?? Because it will free-wheel a tiny bit now and doesn't require as much force to move, but it won't free-wheel for a full turn. And, I went for a pretty good test drive last night and used the brakes a LOT and hard at the end, leaving the front left rotor only slightly warm, front right rotor cool, and back rotor too hot to touch for more than 1/3rd a second.

Is this natural...?? My intuition says it is not.

The rear brake pads were replaced with EBC brake pads. Could the EBC pads be just a touch thicker and be the source of this remaining possible trouble...??

Thanks.

(Addendum - Garrie is awesome... Charges very fair. Is very open minded AND thorough!!)

 

[Mellow]

Yes, it won't freewheel a lot, there's always some friction against the pads / rotor.

The front rotors get the advantage of being more exposed to air vs the rear so will cool off more quickly and there's 2 of them to spread out the front braking effort. The rear shouldn't be all that hot... but, could just be you're more sensitive to the issue now... it might still need another flush as it takes some of us a couple times to get it just right. Sounds like it's an improvement so that's good.

 

[Obo]

Still sounds like something isn't just right...

1. did he replace the SMC at the front? This part is known to be an issue and is better replaced vs rebuilt. Rebuilding doesn't always fix the internal corrosion.

2. the rear caliper mounting bracket can also be damaged and ends up with "fluted spirals" in it. This too can cause issues. There's a photo here somewhere.

Photo compliments of @Igofar in this brake thread: https://www.st-owners.com/forums/threads/st1300-rear-brakes.182525/#post-2419960


3. Igofar always says to only use OEM pads... OEM pads are thicker in the rear, and thinner in the front. They have the metal cage behind them and they have a white spacer between the pad backing plate and the cage to prevent the heat from cooking the fluid. EBC chose to cut corners and not include the cage and or spacer. They also decided to make one thickeness pads. They chose the thicker pads for both front & rear which does not allow the front pads to return to a full rest position away from the rotor. This causes the pads to ride on the rotor, wearing both the pads and the rotors faster, and always applying the rear brake due to the linked system. This is what causes the rear brakes to drag on most bikes.

Long story short any one, or a combination of these can cause brake drag.

 

[Sadlsor]

Still sounds like something isn't just right...
<SNIP --- good stuff>
Long story short any one, or a combination of these can cause brake drag.

 

[The Dark Shadow]

Still sounds like something isn't just right...

1. did he replace the SMC at the front? This part is known to be an issue and is better replaced vs rebuilt. Rebuilding doesn't always fix the internal corrosion.

2. the rear caliper mounting bracket can also be damaged and ends up with "fluted spirals" in it. This too can cause issues. There's a photo here somewhere.

Photo compliments of @Igofar in this brake thread: https://www.st-owners.com/forums/threads/st1300-rear-brakes.182525/#post-2419960


3. Igofar always says to only use OEM pads... OEM pads are thicker in the rear, and thinner in the front. They have the metal cage behind them and they have a white spacer between the pad backing plate and the cage to prevent the heat from cooking the fluid. EBC chose to cut corners and not include the cage and or spacer. They also decided to make one thickeness pads. They chose the thicker pads for both front & rear which does not allow the front pads to return to a full rest position away from the rotor. This causes the pads to ride on the rotor, wearing both the pads and the rotors faster, and always applying the rear brake due to the linked system. This is what causes the rear brakes to drag on most bikes.

Long story short any one, or a combination of these can cause brake drag.

Thanks for that. Since the SMC seems in fine condition, and linked braking system works as it should, the #3 that you detail seems like the best candidate to try first.

 

[MidLife]

Okay, quick follow up question...

....... it will free-wheel a tiny bit now and doesn't require as much force to move, but it won't free-wheel for a full turn. .....

(Addendum - Garrie is awesome... Charges very fair. Is very open minded AND thorough!!)

Mine was just worked on by an old timer mech who knows the ST and I get two free turns.

One quick test you might ask Garrie to help you perform is to relieve all pressure to the rear (open the bleeders) and then spin the wheel.

1) If it spins freely, unfortunately this points to a hydraulic issue.

2) If it still drags as before, then you have a caliper issue.

3) ....if it only slightly improves.....than you have issues with both!

 

[The Dark Shadow]

Mine was just worked on by an old timer mech who knows the ST and I get two free turns.

One quick test you might ask Garrie to help you perform is to relieve all pressure to the rear (open the bleeders) and then spin the wheel.

1) If it spins freely, unfortunately this points to a hydraulic issue.

2) If it still drags as before, then you have a caliper issue.

3) ....if it only slightly improves.....than you have issues with both!

That's a great idea!! Thanks.

 

[Andrew Shadow]

Sorry, but no that is not normal. The rear wheel should free-wheel quite easily if everything is working normally. It should easily do well past one full rotation and get at least close to two.
After normal braking* my rear rotor is only slightly hotter than the front one. I can easily grab a hold of it and hold on to it. I have measured it with a temperature gun after getting home and it is only between 10 to 15 degrees F hotter than the front rotor. I have never checked the temperatures after hard braking. If I was able to ride I would go do some hard braking for you and take some temperature readings to see what the difference is under those conditions, but unfortunately I still can't wear a helmet after a recent surgery.
* Normal braking being the type of braking that a person would do driving through their neighbourhood to get home and pulling in to their driveway, not panic or hard stops.

I understand that this involves money in parts and labour for you but, if you want it fixed correctly, my recommendation to you would be to not waste any time or money doing anything until the SMC has been replaced and a complete flush and bleed, not just a bleed, of the brake hydraulic system has been accomplished ensuring that the procedure in the Honda service manual has been followed to a tee. Your brake system has a history of dragging the rear brake. While I obviously can not state this with absolute certainty, I can state with significant confidence that your SMC is compromised and on its way out. Change it now and fix the problem rather than treat the symptom. Overhauling the SMC isn't worth the effort. Based on the history of many attempts on this forum, it usually is not successful or is only a temporary solution resulting in eventual replacement later on. More often than not the SMC bore is worn oval relegating it to scrap.

I would not use EBC pads on an ST1300 period. There have just been way to many people on this forum who have had brake problems, including dragging brakes, and the solution to the problem was getting rid of the EBC pads and replacing them with Honda OEM pads. This includes having a dragging rear brake due to having EBC pads fitted only in the front, which has caused the rear brake to drag even if the SMC is in perfect working order. It seems that the EBC pads are often not the correct thickness which results in the front brakes dragging which activates the SMC and causes the rear brake to drag. For some reason EBC just doesn't seem to get it right with ST1300 brake pads. If you need new brake pads, get Honda pads. If the pads that were removed are not completely worn AND they are Honda pads, put them back on for now- they are preferable to the new EBC pads based on the history reported on this forum.

 

[The Dark Shadow]

Sorry, but no that is not normal. The rear wheel should free-wheel quite easily if everything is working normally. It should easily do well past one full rotation and get at least close to two.
After normal braking* my rear rotor is only slightly hotter than the front one. I can easily grab a hold of it and hold on to it. I have measured it with a temperature gun after getting home and it is only between 10 to 15 degrees F hotter than the front rotor. I have never checked the temperatures after hard braking. If I was able to ride I would go do some hard braking for you and take some temperature readings to see what the difference is under those conditions, but unfortunately I still can't wear a helmet after a recent surgery.
* Normal braking being the type of braking that a person would do driving through their neighbourhood to get home and pulling in to their driveway, not panic or hard stops.

I understand that this involves money in parts and labour for you but, if you want it fixed correctly, my recommendation to you would be to not waste any time or money doing anything until the SMC has been replaced and a complete flush and bleed, not just a bleed, of the brake hydraulic system has been accomplished ensuring that the procedure in the Honda service manual has been followed to a tee. Your brake system has a history of dragging the rear brake. While I obviously can not state this with absolute certainty, I can state with significant confidence that your SMC is compromised and on its way out. Change it now and fix the problem rather than treat the symptom. Overhauling the SMC isn't worth the effort. Based on the history of many attempts on this forum, it usually is not successful or is only a temporary solution resulting in eventual replacement later on. More often than not the SMC bore is worn oval relegating it to scrap.

I would not use EBC pads on an ST1300 period. There have just been way to many people on this forum who have had brake problems, including dragging brakes, and the solution to the problem was getting rid of the EBC pads and replacing them with Honda OEM pads. This includes having a dragging rear brake due to having EBC pads fitted only in the front, which has caused the rear brake to drag even if the SMC is in perfect working order. It seems that the EBC pads are often not the correct thickness which results in the front brakes dragging which activates the SMC and causes the rear brake to drag. For some reason EBC just doesn't seem to get it right with ST1300 brake pads. If you need new brake pads, get Honda pads. If the pads that were removed are not completely worn AND they are Honda pads, put them back on for now- they are preferable to the new EBC pads based on the history reported on this forum.

Thanks again for your input, Andrew. I'm not convinced that the SMC is the problem, since it appears to be working as it should. The back has NEW EBC pads, which you and Obo pointed out can clearly cause troubles. I'll start here. I've ordered some OEM rear pads, and I'll see first if that helps. Also, I'll check to see if the front pads are EBC or OEM... Should be easy enough to check, since the EBC pads seem to be split into 2 pads per plate, and the Honda OEM are 4 per plate.

 

[Al st1100]

Thanks again for your input, Andrew. I'm not convinced that the SMC is the problem, since it appears to be working as it should. The back has NEW EBC pads, which you and Obo pointed out can clearly cause troubles. I'll start here. I've ordered some OEM rear pads, and I'll see first if that helps. Also, I'll check to see if the front pads are EBC or OEM... Should be easy enough to check, since the EBC pads seem to be split into 2 pads per plate, and the Honda OEM are 4 per plate.

what do they say about doing the same thing over and expecting different results. Diagnos it and stop guessing. Do as MidLife pointed out .

 

[Al st1100]

The rear brake pads were replaced with EBC brake pads. Could the EBC pads be just a touch thicker and be the source of this remaining possible trouble...??

no

 

[The Dark Shadow]

Thanks again for your input, Andrew. I'm not convinced that the SMC is the problem, since it appears to be working as it should. The back has NEW EBC pads, which you and Obo pointed out can clearly cause troubles. I'll start here. I've ordered some OEM rear pads, and I'll see first if that helps. Also, I'll check to see if the front pads are EBC or OEM... Should be easy enough to check, since the EBC pads seem to be split into 2 pads per plate, and the Honda OEM are 4 per plate.

The difference between EBC and OEM pads has been reported. It is reported by some that EBC pads are a known problem. Hence, I have diagnosed that I should get rid of the EBC pads. This is my next step. And it should be easy to see if the front pads are EBC or OEM. Low hanging fruit.

 

[Andrew Shadow]

I'm not convinced that the SMC is the problem, since it appears to be working as it should.

Not sure if you are aware/have read of the simple test of the SMC to give you an idea of its condition.
Just in case, here it is.

*** CAUTION ***
When you are performing this test it is possible to push on the SMC hard enough to push the motorcycle forward enough to allow the centre-stand up to fold up. This could result in the motorcycle falling on you. For safety, chock the front wheel and or strap the centre-stand to the front wheel to make sure that it can not fold up on you during the test.

If you have someone to help you:
With the motorcycle on the centre-stand;
- one person rotates the rear wheel while the other person pivots the SMC assembly upwards in the direction that the brake rotor rotates when the motorcycle is moving forward.

If you are doing this alone:
With the motorcycle on the centre-stand;
- Lie down along the left side of the motorcycle with your head at the front wheel end.
- Rotate the rear wheel with your foot while simultaneously pivoting the SMC as stated above.

- A normally functioning SMC should stop the rear wheel rotation immediately as soon as the SMC is pivoted. You should not be able to turn the rear wheel at all unless you are applying insufficient force to pivoting the SMC.

This second part is probably the more important part of the test.
- When you release the upward pressure on the SMC the rear wheel should IMMEDIATELY be free to turn. If it does not happen fully and immediately, this is an indication of an SMC problem.

It could be that the SMC piston is slow to return in it's bore for many different reasons.
It can also be as simple as the bearing and bushing that the SMC pivots on are not free to rotate. These need to be cleaned and re-greased every once in a while to make sure that they are not binding.

As stated many times on this forum, with properly functioning brakes and drive-line, the rear wheel should easily rotate after a good shove on the rear tire with one's foot.

 

[Al st1100]

Showing results for on a disc brake system how much does the piston retract after releasing pressure
When the pressure is released the pad stays in position and lightly ride on the rotor. The piston seal retracts the piston
How far should a caliper piston retract?


Measure the retraction of the piston. If the movement is anywhere between 4 to 6 thousandths, the square cut seal is working properly. If the caliper piston does not retract back into its housing during these tests, you know that the square cut seal is compromised.

 

[MidLife]

Showing results for on a disc brake system how much does the piston retract after releasing pressure
When the pressure is released the pad stays in position and lightly ride on the rotor. The piston seal retracts the piston
How far should a caliper piston retract?


Measure the retraction of the piston. If the movement is anywhere between 4 to 6 thousandths, the square cut seal is working properly. If the caliper piston does not retract back into its housing during these tests, you know that the square cut seal is compromised.

Illustration at 4:45 here.

 

[The Dark Shadow]

Illustration at 4:45 here.

"Square section seal" is beyond my knowledge...

 

[MidLife]

"Square section seal" is beyond my knowledge...

...WAS beyond your knowledge! Now you know that's what seals the hydraulic fluid around your caliper pistons and causes slight piston retraction if there is no hydraulic blockage or too much crud by the pistons.

Also known as square O-Ring.

 

[ST Gui]

Glad to hear this may on the right track now for you!

Likewise Dark Shadow. One of the most frustrating things I can think of is having a problem offhandedly dismissed because someone doesn't take the time to listen and worse- doesn't know or will admit when they're out of their depth.

Here's hoping there's light at the end of the tunnel and that it's not on the front of the train.

 

[The Dark Shadow]

Mine was just worked on by an old timer mech who knows the ST and I get two free turns.

One quick test you might ask Garrie to help you perform is to relieve all pressure to the rear (open the bleeders) and then spin the wheel.

1) If it spins freely, unfortunately this points to a hydraulic issue.

2) If it still drags as before, then you have a caliper issue.

3) ....if it only slightly improves.....than you have issues with both!

Questions:

If I open the bleeder valves, do I risk air entering the system...??

Also, I noticed in another comment that someone mentioned sometimes it's necessary to bleed/flush the system more than once for optimal results. Is this correct...?

Lastly, what is the difference between "bleeding & replacing fluid" versus "flushing the fluid"...? Just different words for the same thing...??

 

[Ryan_B]

If I open the bleeder valves, do I risk air entering the system...??

Yes, you need to apply pressure (on whatever brake pedal or handle you are working on) when you open the bleeder. You will get a little spray of fluid, tighten it back up and repeat as many times as you like (lots if you trying to flush the entire system).

Alternatively, get one of these: (LINK)


Great tool, I have been bleeding/flushing brakes for 25 years. I didn't realize how nice these one-way valves are until @Igofar told me to get one for my rear brakes a couple of years ago. You just hook it to your bleeder valve, open the bleeder up and pump the pedal/handle until you have flushed the system (keep in mind you must refill reservoirs so you do not introduce more air and there is sufficient brake fluid).

Lastly, what is the difference between "bleeding & replacing fluid" versus "flushing the fluid"...? Just different words for the same thing...??

Terms that are generally used interchangeably. Personally, I would say "bleed the brakes" if you have soft pedal/handle feel, the objective is to remove entrapped air. "Flush the brakes" would mean replace the fluid completely.

I have been quietly watching your posts and hoping you would give it a try. You got this!

Ryan


*EDIT* To answer your question directly, since you were quoting MidLife. Yes, his method risks the possibility of introducing air to the system, but he is trying to help diagnose if it is a hydraulic issue or a mechanical issue. If you open the bleeder and the rear wheel turns free, you have a brake hydraulic issue. If you open the bleeder and the rear wheel is still tight, you have a mechanical binding issue.