Rear Brake Issue

Mutley

Mutley

Joined
Jan 10, 2008
Messages
33
Age
70
Location
Wyoming, MI
Bike
'06 ST1300
STOC #
5184
Hello! I just brought home my new to me 2005 ST1300 non-ABS. The rear brake pedal goes to the "floor"! It will, however, pump up. Do I have an issue with the rear Master Cylinder?
Also, the SMC clunks alot over bumps.
Thanks for any help!

Gary
 
The ST's linked brakes are quirky and semi-complicated. Research here and get yourself a good understanding of how they work.

Then start with a proper bleed. According to procedure. Short cuts will not get it done right and may have no effect.
 
You may want to chat with me for a few minutes first, as I may be able to save you some drama and frustration doing your bleed, and inspections.
Standing by the white courtesy phone if needed :WCP1:
 
Clunking sounds like a SMC rebuild or replace!

You didn't say how many miles are on it.
 
jfheath said:
You don't know what proper bleeding is, until you have talked with Larry.
Click to expand...
Thanks for that John, I just spit my soda on the keyboard :rofl1:
Now I don't care what you say, that there was funny :crackup:
 
20k on the odo.

Igofar, I will call when I do this! Thank you!
I just got the bike home, got the insurance, registration, title in order. Doing a good check over to see if other problems exsist before tearing into this.
I assumed the Factory Honda bleeding procedure was best.
 
Response to my conversation with Igofar and what finally fixed the issue!


Heya Larry,

Sorry I didn't get back sooner.
I discovered the problem with the rear brake! Seems the upper cup in the SMC was all wrinkled up and flipped over. I got a rebuilt kit from and installed it. Easy right? But...now for the bleeding.
As you alerted me to, it was a PITA!

What I did:
Used my MightyVac to evacuate all the old fluid and start the bleeding process. So good so far, right?

Following the Honda Service Manual, I bled exactly as stated, with the MightyVac. Seems I got nowhere, lots of air, seems I was missing something! I started over, following procedure again, no rear brake!

Finally, with the help of my wonderful wife, we proceeded using hand and foot pressure via the Master Cylinders! Success! We got it. Road test? Everything check OK!

I will take a pic of the part and send it along.

PS: A good friend and great Honda tech said he'd never seen this on an ST. Maybe the fluid was contaminated causing the cup to fail.

Anyways...all good!

Happy riding,
Gary (Mutley)
 
Mutley said:
Response to my conversation with Igofar and what finally fixed the issue!


Heya Larry,

Sorry I didn't get back sooner.
I discovered the problem with the rear brake! Seems the upper cup in the SMC was all wrinkled up and flipped over. I got a rebuilt kit from and installed it. Easy right? But...now for the bleeding.
As you alerted me to, it was a PITA!

What I did:
Used my MightyVac to evacuate all the old fluid and start the bleeding process. So good so far, right?

Following the Honda Service Manual, I bled exactly as stated, with the MightyVac. Seems I got nowhere, lots of air, seems I was missing something! I started over, following procedure again, no rear brake!

Finally, with the help of my wonderful wife, we proceeded using hand and foot pressure via the Master Cylinders! Success! We got it. Road test? Everything check OK!

I will take a pic of the part and send it along.

PS: A good friend and great Honda tech said he'd never seen this on an ST. Maybe the fluid was contaminated causing the cup to fail.

Anyways...all good!

Happy riding,
Gary (Mutley)
Click to expand...

If you are describing the upper rubber cup on the piston I've seen that often. Which also could mean that the piston fins contacted the bore (are the edges of the fins on the old piston shiny?)
If so, a rebuild kit may not completely fix or repair your issue.
I also suspect if it was that bad, that the cartridge with the small filter behind the SMC is probably clogged with crap, and if that is/was the case, I would suggest replacing the entire unit and not try to rebuild it. The service manual warns against taking the piston assembly apart, as it is measured/set at the factory.
I'm still available to talk if you have any questions.
Igofar
 
Let me give a GREAT BIG shout out and thank you! to Larry (igofar) for all the help and and insight for this project! He was very helpful in telling me about all things linked brakes.

Larry, you're the best! Thank you for your time and instructions!
 
You must log in or register to reply here.
Back
Top Bottom