I have replace brake piston seals and pads and I am unable to bleed the 2 outer pistons operated by the front lever, is there a problem with the proportional valve, if so is there a fix?
Michelle
Michelle
st1300 brake problems
- Thread starter oldbirdonabike
- Start date
Blrfl
Natural Rider Enhancement
Front or rear wheel? The front outers are actuated directly by the lever and the rear outers by a secondary master cylinder mounted on the left front brake.
The brakes on these bikes have to be bled in a sequence outlined in the service manual or the system won't be purged properly.
--Mark
The brakes on these bikes have to be bled in a sequence outlined in the service manual or the system won't be purged properly.
--Mark
Mark aka MileHigh did an excellent job of the procedure here
https://www.st-owners.com/forums/showthread.php?68913
if that helps.
https://www.st-owners.com/forums/showthread.php?68913
if that helps.
I do have a work shop manual but it doesn't cover the lack off brake fluid from the front lever when I took the caliper off the outer pistons were now were near the pads I'm sure its something to do with the proportional valve as now fluid is coming from it.
Blrfl
Natural Rider Enhancement
Let's go back a step: Are you trying to bleed the outer pistons on the front caliper(s) or the rear?
--Mark
--Mark
What year bike and which caliper are you trying to bleed? There was a recall on 2003 and 2004 st's on the proportional valve leak...
Its a 2003 I have had it from new and wasn't informed about a recall about that problem as I think it could be something to do with it.
The rear caliper thats operated by the front lever, the foot pedal bleed ok.
I did use a proper suction bleeding tool for the job as I have changed the fluid before.
The rear caliper thats operated by the front lever, the foot pedal bleed ok.
I did use a proper suction bleeding tool for the job as I have changed the fluid before.
No rear pistons are actuated by the front lever........
The two outer pistons, as has been noted, are operated by the SMC on the front left fork leg, this is activated when the front or rear brake is applied and the SMC is activated as the left caliper moves up....
You should follow the recommended procedure mentioned before.
I wrote a full brake system operation description on here before, I will go find it and post a link.
Edit; Found it.... Post #9 on this thread.
https://www.st-owners.com/forums/showthread.php?87077-Rear-Brake-Service-Function-Test
The two outer pistons, as has been noted, are operated by the SMC on the front left fork leg, this is activated when the front or rear brake is applied and the SMC is activated as the left caliper moves up....
You should follow the recommended procedure mentioned before.
I wrote a full brake system operation description on here before, I will go find it and post a link.
Edit; Found it.... Post #9 on this thread.
https://www.st-owners.com/forums/showthread.php?87077-Rear-Brake-Service-Function-Test
https://www.st-owners.com/forums/showthread.php?2349-ST1300-Brake-Proportioning-Control-Valve-(Bike-Years-2003-2004) This is the recall info.
Basically brake fluid will leak from the bottom of the proporting valve, this will run the rear resevour dry causing brake failure. Faulty seals
The front brake does not activate the rear brake only the cylinder on the front left side caliper will activate the center piston on the rear caliper in hard braking.
You must follow the bleeding sequence to properly bleed the brakes. If you are using a vacumn pump you may still have to press the rear brake pedal to get any flow.
Honda did not want replace my proportioning valve, they stated that it was normal wear and tear because the dealer had done the recall check on it to verify it was ok or so Mother Honda's records showed. But when traced back to the dealer who was suposed to do the work was no record of it! So I got a call from Honda and they agreed to replace it.