Rear brakes still dragging with new SMC & RMC - alignment problem?

Kevin_SK_ST

Kevin_SK_ST

Joined
Mar 13, 2019
Messages
7
Age
54
Location
Regina, Saskatchewan CANADA
Hey all;

This being my first post it may as well be here in the brakes section.
I had read so many posts here about this topic with lots of great direction that certainly saved me plenty of headache.

My bike is a 2003 w/o ABS so thank heaven for that. I have owned it for a few years and the brakes seemed to work well until this spring.
I took my wheels off to get new tires put on and was able to reassemble successfully with some effort.
I rode it for a few weeks and then noticed more (there always was a little) brake scraping when pushing it around in the garage.
Took it out for a 5 km ride with light even braking front and back. The rear disc was too hot to touch and the front ones were not near as bad.

After my research here on the forum I called my dealer to order re-build kits for the SMC & RMC.
These kits were back-ordered for over 2 months. That is an eternity for any motorcycle rider in Canada and especially in Saskatchewan.
The complete units were available much quicker and at quite a bit more cost.
However, to quote JFHeath, "ST parts will not be available forever" so I decided to just spend the money and order a new SMC & RMC.
It looks like there is a part number change up on the SMC anyway and mine is probably original to 2003 so not a waste of money in my mind.
In the mean time I checked over the rest of the calipers and cleaned all the piston (w/o removal) and got it ready to put in the new parts.

The new parts arrived and I installed them. I did have to bleed the system twice to get a good firm handle & pedal but it seemed to go pretty well.
I then tested out the brakes before putting everything back together and the rear brakes still dragged when using the pedal. I came back the next day and bled
the system again and found a few small bubbles but I'm not sure how much small amounts of air in the system would keep the pistons from sucking back.
Still the same result.

Time to call in the pros. I went and spoke to my local dealer about the problem and the service writer even knew about the complicated bleeding procedure.
So I booked it in and brought it down. I have known this shop for many years and trust them with any of my equipment.

I just spoke to them and they had rebuilt the rear caliper with new seals, bled the system and took it for a test ride.
Still dragging slightly. The technician started working with the rear brake bracket and stopper bolt and found an alignment problem.
He said when he takes out the stopper bolt the brakes come into alignment better and stop dragging.
They tried a different stopper bolt (off a similar bike) and it didn't seem to help.
The brake bracket is also on back-order until end of July to mid-August so no way to try that easily.

Here is my question - Could it be the bracket and/or stopper bolt or just the mounting pins? What else could be the cause?

These bikes are not common here in Canada like they are in Europe.
My wife and I will be in the UK in July so I am tempted to order parts at a London Honda dealer and pick them up when I am there and bring them home.

Thank you so much for all those that took the time to post about this and help others.
 
The rear brackets have been known to get messed up. I had one a number of years ago, go bad on me, once I replaced it and rebuilt the SMC and rear caliper, all was well again.

Also, Larry (igofar) contacted me about an issue with one bike he was working on, so I sent him an extra bracket I had, and it to was out of sorts! So, the rear bracket can be an issue.

Maybe Larry can post the picture he sent me of that one?
 
Welcome to the forum Kevin.
Hope you sort out your brake problem.
 
Just saw your post....I'm going to try and attach the name of the thread where I posted pictures of the damage found on the rear caliper of a customers bike.
If your dealer indicates that removing the stopper plug allows the brakes to work correctly, you my friend, have a bent guide pin. They are hard to see with your naked eye.
The stopper bolt MUST be tightened BEFORE you tighten the axle bolt, or you will risk damage to the bracket pin.
In the pictures, you'll see that the movement almost cut flutes into the bracket itself, as well as pounded the pad retaining clip flat.
You'll also see damage on the ledge where the front clip sits.
Let us know what you find.
Igofar (Larry)
"Howling" noise when using the brake pedal
 
When I had my rear brake apart, I cross-threaded a the guide pin on the bracket slightly when I installed it. It was barely noticeable, but it resulted in dragging brakes and very uneven pad wear. It would basically only wear one end of one pads and the other end of the opposite pad - a clear sign that the pads were not aligned with the disc. I wore out two sets of pads until I finally found the problem. I removed the pin and installed it making sure it went in straight, and problem was resolved...
 
I've seen this alot lately, mostly when folks try and replace their pads without removing the rear wheel, or by trying to take the back side of the caliper off to save time.
I've also seen several bent pins, due to loose stopper bolts, tightening the axle before the stopper bolt, and when the secondary master cylinder gives up the ghost and locks up, the weight of the bike forcing against it damages it.
 
Igofar said:
I've seen this alot lately, mostly when folks try and replace their pads without removing the rear wheel, or by trying to take the back side of the caliper off to save time.
Click to expand...

Oh, come on Larry, who would do something like that? :rolleyes:
 
Thank you so much for all the replies. I called the dealer this morning and spoke to the parts dept.
The stopper bolt and guide pin is available in Vancouver so I had him order them.
I guess there was one detail I missed and semi-forgot. Last fall I switch out all the pads and the rears were worn unevenly
so it sounds like this alignment problem was there before and the pads wore themselves back to alignment; not ideal.
If these parts don't solve the issue I guess I will go bracket hunting.
I will see if I can get parts in Canada/US before looking in the UK.

This will be my second trip to England and the Ace Cafe still didn't make the itinerary.
It's also nice seeing STs everywhere we go. We were in Sluis, Netherlands last year and I
saw a dozen or more parked near the canal.

Thanks again!
Kevin
 
Kevin_SK_ST said:
Thank you so much for all the replies. I called the dealer this morning and spoke to the parts dept.
The stopper bolt and guide pin is available in Vancouver so I had him order them.
I guess there was one detail I missed and semi-forgot. Last fall I switch out all the pads and the rears were worn unevenly
so it sounds like this alignment problem was there before and the pads wore themselves back to alignment; not ideal.
If these parts don't solve the issue I guess I will go bracket hunting.
I will see if I can get parts in Canada/US before looking in the UK.

This will be my second trip to England and the Ace Cafe still didn't make the itinerary.
It's also nice seeing STs everywhere we go. We were in Sluis, Netherlands last year and I
saw a dozen or more parked near the canal.

Thanks again!
Kevin
Click to expand...

Kevin, I wish you all the best in sorting your bikes issues out, and in an effort to save you some drama ordering parts you may not need, I will point out that neither the guide pin, nor the stopper bolt, bend. The damage is caused to the soft aluminum bracket. The steel pin either pushes into the bracket, or damages the threaded hole in the bracket from leverage. The part you'll need to locate, if this is indeed your problem, would be the bracket itself.
 
Thanks Igofar. I will look in the US and see what I can find.
I seem to remember that there was a slight gap between the bracket and the swing arm when I had everything torqued.
Is that a tell-tale sign that the bracket is warped?
 
And don't bother asking SupraSabre if he has a spare bracket, he sent his one and only spare to Larry, only to find out it was bent up! :doh1:
 
Replaced my rear brakes this week, 04 ST1300, while replacing the rear tire. Took the caliper off, while wheel off. Used a toothbrush and brake cleaner and scrubbed around each of the 3 pistons while they were still extended. Pushed the outside two pistons in by hand. The middle piston required a small c clamp but went in relatively easily. Reinstalled the pads, ensuring they are both properly seated in inside bracket. Now after riding, my rear caliper is quite warm to touch. Rechecked to ensure the pads are properly seated in bracket, after taking caliper off again. Pushed pistons in again, quite smoothly. Rear brake fluid remains at top (fill) line. Is this a secondary master cylinder issue. I have never dealt with that before. Anyone have guidance? What do I do next? I am hoping this is just regular heat on rotor from newly installed pads, but rotor is hot enough that I can't hold it with my fingers. I asked my wife to lick it to see how hot she thought it was. She didn't like that!!!!
 
There are many others on here more qualified to answer but I will impart a thought or two.
It sounds like the rear caliper needs rebuilding and/or the rear master cylinder.
Since the bleeding process is so involved I would rebuild both of these.
If you are up to it rebuild the secondary master cylinder on the front left fork while you are at it.
As you can see from the brake system diagram if it's the center piston holding up it more than likely not the secondary master.
 

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Happy Rob said:
Replaced my rear brakes this week, 04 ST1300, while replacing the rear tire. Took the caliper off, while wheel off. Used a toothbrush and brake cleaner and scrubbed around each of the 3 pistons while they were still extended. Pushed the outside two pistons in by hand. The middle piston required a small c clamp but went in relatively easily. Reinstalled the pads, ensuring they are both properly seated in inside bracket. Now after riding, my rear caliper is quite warm to touch. Rechecked to ensure the pads are properly seated in bracket, after taking caliper off again. Pushed pistons in again, quite smoothly. Rear brake fluid remains at top (fill) line. Is this a secondary master cylinder issue. I have never dealt with that before. Anyone have guidance? What do I do next? I am hoping this is just regular heat on rotor from newly installed pads, but rotor is hot enough that I can't hold it with my fingers. I asked my wife to lick it to see how hot she thought it was. She didn't like that!!!!
Click to expand...
do about 5 hi speed stops using the front brakes only and see how hot those front rotors get . Next time you drive your car see how hot those rotors get. As long as you can spin the back wheel after a long ride( on the center stand) your good , IMO.
 
Al st1100. thanks for the reply. I have rode the bike for a couple of days now. Using both foot and handle bar brakes. I hop off and check front and back rotors. Fronts are both cool to touch, but the back it quite hot. Hot enough that I am not able to hold the rotor with bare fingers. When up on center stand, rear wheel spins but not exactly freely,there is some drag. Zero drag on front wheel.
Is this just regular brake pad wear in? Or is there an issue with pistons in caliper?
 
Happy Rob said:
Al st1100. thanks for the reply. I have rode the bike for a couple of days now. Using both foot and handle bar brakes. I hop off and check front and back rotors. Fronts are both cool to touch, but the back it quite hot. Hot enough that I am not able to hold the rotor with bare fingers. When up on center stand, rear wheel spins but not exactly freely,there is some drag. Zero drag on front wheel.
Is this just regular brake pad wear in? Or is there an issue with pistons in caliper?
Click to expand...

Just want to point out a couple things...
NEVER use spray brake cleaner on your caliper pistons, the spray will make your seals swell and cause the brakes to drag.
You can use Simple green, windex, soap and water, or brake fluid.
Did you extend the pistons out a little bit to clean the ring of crap off before you pushed them back into the caliper?
If not, you may have pushed crap behind the piston seal...this will cause the brakes to drag.
While you where in there did you clean and lightly lubricate the guide pin?
When you assembled the rear wheel did you tighten the stopper bolt (14mm head) BEFORE you tightened the Axle nut? (very important)
Did you inspect the flange bearings in the rear wheel when it was off? Moly Paste?....or I should say the correct moly paste?
I would not jump the gun and start rebuilding stuff without finding the cause of the problem first.
A lot of folks rebuild the rear caliper because they think that's whats causing the wheel to drag, when in fact its more likely that its the SMC, front calipers, bent guide pin, or wrong pads.
After you take a short ride, you should be able to pull up to a stop, place the bike on the center stand, and with one firm push downward with your boot, you should be able to get 2 full turns on the rear wheel.
How many miles on your bike?
 
You beat me while I was typing John :rofl1:
Good information though.
 
Hey all;
Update to the rear brake issues I was having.

Recap - The dealer technician did everything he could to get the brakes freed up without replacing the rear caliper bracket as it has been on back order. It was ridable but not ideal yet.

Back from vacation and the part arrived. Took it back to the dealer and they installed it and took it for a test ride.
PROBLEM SOLVED!

That bracket is a beefy piece and it's quite surprising that it could become bent/warped.

Thanks to everyone for your input.
Ride safe.
Kevin
 
Once, I let the dealer install new brake pads. They didn't bother to clean anything and shoved the dirty pistons into the seals. Of course, the brakes were dragging. I extended and thoroughly cleaned the pistons and lubricated the slide pins. I've not had a problem since.
 
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