ST1300 Front Brake Dragging

jbhunsaker

jbhunsaker

Joined
May 26, 2018
Messages
14
Location
Phoenix area
Bike
2008 ST1300A
I flushed the brake system using the 7-point procedure as a regular maintenance item. I had no previous braking issues but afterward there was very little play in the front brake handle and now the front brakes drag. I can decompress them a little using a screwdriver as a wedge and the tire spins freely until I apply the brakes again then they drag. Rear brake is fine and if I only use the rear brake the front ones do not drag. Could I have gotten contaminant in the front master cylinder when I wiped it clean that prevents it from operating properly? Is my first step to rebuild the front master cylinder? Thank you!
 
When is the last time you disassembled the brake calipers and cleaned the pistons, and caliper bolts/pin - re-lub etc.? IGOFAR is not far away from you if you need further assistance
 
When was the last time the front calipers were cleaned - by this I mean the outsides of the pistons with a shoelace dipped in brake fluid? If more than a couple of years, you might be due for a thorough remove and clean and replace the front calipers as @JohnK suggested. I would hesitate to disassemble the calipers themselves, unless you find excessive corrosion on the outsides of the pistons.
 
I've never cleaned the calipers. Like I said there were no problems before flushing the fluid. I ordered a master cylinder rebuild kit today, it will take a while to get it. Thank you Igofar for standing by, I follow you and read lots of your posts. If the m/c rebuild doesn't work I will definitely reach out!
 
It’s not going to be master cylinder rebuild kit related….
If you want to call, I can run you through a couple inspections, and get you pointed in the right direction , before you start throwing money at the wrong causes.
 
If you removed the lever, check that the pushrod is seated correctly in the cup. Pre 2008 bike only.

If you didn't then I'd reach out to Larry asap. Its easier to work out what has happened if you can answer questions about what you did. There are a number of things that could cause this - but without the dialogue I would just be guessing.

After bleeding, I often tie the brake lever back to the bars and leave overnight. It helps dislodge the last remaining micro bubbles in the line. Either a cable tie or a rubber guy.

I've had the front wheel locked solid after bleeding. Couldn't shift the wheel at all the following morning. I'd got the bleed tubes out, and tools to remove the caliper, and a screwdriver to open the reservoir......

....and then I noticed the rubber guy still holding the brake lever back !
 
Igofar said:
It’s not going to be master cylinder rebuild kit related….
If you want to call, I can run you through a couple inspections, and get you pointed in the right direction , before you start throwing money at the wrong causes.
Click to expand...
I don't know how to call the white courtesy phone. Can you tell me?
 
jbhunsaker said:
I don't know how to call the white courtesy phone. Can you tell me?
Click to expand...
Click on his avatar / picture of the phone.
A window pops up.
At the bottom of that window click "Start conversation", enter your name and phone number, click "Start conversation" button at the bottom.
Wait for the fun to begin!
 
Sadlsor said:
Click on his avatar / picture of the phone.
A window pops up.
At the bottom of that window click "Start conversation", enter your name and phone number, click "Start conversation" button at the bottom.
Wait for the fun to begin!
Click to expand...
Thanks! Got it.
 
Sadlsor said:
Click on his avatar / picture of the phone.
A window pops up.
At the bottom of that window click "Start conversation", enter your name and phone number, click "Start conversation" button at the bottom.
Wait for the fun to begin!
Click to expand...
Thanks! Got it.
 
Larry spent over two hours with me on the phone today. He guided me very meticulously through several diagnostic activities, had me send photos, and he sent photos back to help explain what he was talking about. WOW! I've never been helped like this in all my riding days.
The main culprit is is the Secondary Master Cylinder attached to the left front caliper. Apparently when I flushed the brake fluid, it broke free some debris that made it stick in a way that won't let the front brakes fully release. He has sent me a complete parts list, with numbers, so I can order everything I need.
Truly an ST Whisperer.
 
Larry the ST Whisperer and Snake Handler Extraordinaire is, indeed, quite a rare individual.
Did he play guitar for you?
 
Seriously?
dry and dirty guide pins, dirty pistons, swollen grommets from using spray brake cleaner, bent clips, misaligned front forks, a frozen SMC, a clogged return port, stirring up crap in your clogged up SMC, preventing the two outer pistons on the left front caliper from releasing.....I wonder if that would prevent the front wheel from turning? :rofl1: etc.
And either brake lever operates the left front brake caliper, which the damaged SMC happens to be attached to, and you can’t figure out why the front wheel could drag? :rofl1:
We’ve only spent a bit on the phone, but already identified a couple damaged parts.
We will know more in a couple weeks when I can get eyes on it myself.
 
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