Front Brake Caliper Center Cylinder No Fluid, No Movement

Joined
Dec 28, 2011
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24
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OAK LAWN ,IL
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st1300
just finished brake bleeding, my proportional valve was really bad.
during this procedure I found I cant bleed center valve on front caliper ( dry , no fluid at all) . Also center caliper on both sides is not moving under pressure.
I can press it in , but there is no brake fluid behind to push it out.
did somebody experience this ? Can it be fixed or do I need new calipers on front ?
 

Reginald

cyclepoke
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Georgetown, Tx
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8898
Re: FRINT BRAKE CALIPER CENTER CYLINDER NO BRAKE FLUID NO MOVEMENT

Several things could be wrong not just the calipers. I'd say you could rebuild the calipers. I'd also say you need to see where brake fluid is flowing and not flowing. Its the PCV, balance valves on front finder, the SMC, and hoses that could be plugged in addition.

Disconnect the hose from the rear peddle to the front center valve at the caliper, is brake fluid there? Try to isolate if the problem is just with the caliper or further up the line toward the master cylinder.

Based on the problem you experienced with the PCV, I'd be suspicious of the SMC. Spin the rear wheel (another person here helps) and activate/depress the SMC. When you activate the SMC does the rear wheel brake? Check under the SMC boot is it corroded under it.

Do you have a service manual? If not you might want to get one.

Be sure to protect all your painted surfaces.
 
OP
OP
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OAK LAWN ,IL
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st1300
i was able to bleed PCV , my rear brakes and both front brakes ( top bleeder only ).
rear brake works fine , front to . Only center cylinder on each side of front calipers don't move.

Does anybody knows how center cylinder is connected to system ?
Does it have additional dedicated line?
 
OP
OP
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Dec 28, 2011
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OAK LAWN ,IL
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st1300
Wow it is confused system.
Looking on this schematic , are two rear cylinders actuated with front brake lever ?
And this looks like to bleed center cylinder on front calipers I should actuate rear brake lever.
Wow I have to do it all again.
 

dduelin

Tune my heart to sing Thy grace
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i was able to bleed PCV , my rear brakes and both front brakes ( top bleeder only ).
rear brake works fine , front to . Only center cylinder on each side of front calipers don't move.

Does anybody knows how center cylinder is connected to system ?
Does it have additional dedicated line?
Did you follow the bleed PDF exactly in prescribed sequence? Did you use the foot pedal and/or a vacuum system to bleed the front center bleed valve? That is a very long circuit fed from the rear reservoir through the delay valve then to the calipers. It bleeds very slowly under vacuum alone. If the reservoir bled dry during the bleed of one or the other front caliper center bleed valves there might be a big air space in the circuit.
 

dduelin

Tune my heart to sing Thy grace
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Wow it is confused system.
Looking on this schematic , are two rear cylinders actuated with front brake lever ?
And this looks like to bleed center cylinder on front calipers I should actuate rear brake lever.
Wow I have to do it all again.
The two outer rear pistons are actuated indirectly by the front lever. When the front brake is applied the left front caliper rotates forward and in doing so compresses the secondary master cylinder mounted on the caliper. Fluid pressure builds in the SMC and the two rear outer pistons move. The front wheel has to be turning in a forward direction for the linkage to work. The hand lever is not directly moving the rear pistons.

It's very important to exactly follow the PDF you requested. If done step by step this system takes longer than simple unlinked brakes but it's easy to get a completed job.
 
Last edited:
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Sep 4, 2013
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2010 ST1300
I've not had the joy of bleeding the ST's brake system, but I have done cars and completely rebuilt brake systems on two older Moto Guzzi's. That's when I learned that vacuum bleeders are indispensable for some systems. You can bleed and bleed forever and not get that last bubble out that makes the brakes spongy. A miteyvac system helps and you will develop forearm muscles to rival Popeye's. Some guys here have had luck using nipples with one way valves that allow you to expel brake fluid into a hose but do not admit air when you let up on the brake lever.

Brake fluid is hydroscopic - it absorbs moisture from the air. After a while, you get corrosion inside the calipers that can freeze a brake piston. That's why bleeding and flushing with fresh brake fluid is so important. You will have to follow the bleeding procedure exactly as described in the Honda shop manual.

Good luck!
 

dduelin

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Thank You , I will go over this again.
Larry (Igofar) is the guy that knows the ST1300 brake system as good as anyone and better yet has the knack for understanding and helping when necessary. Hopefully he will chime in here soon with the courtesy phone!
 
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Sorry for the Late reply, was in the garage bleeding brakes :rofl1:
Thanks for the heads up Dave.
If DONCZ will PM me a contact number, I will be glad to call him on my dime today and help him sort things out.
Igofar
 
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North Plainfield, NJ
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'06 ST1300A
Wow it is confused system.
Truer words have not been spoken.

When I first began working on my ST1300, I searched for a brake system schematic, and found the same image that Mr. Reginald mentioned from an earlier thread. While the image was better than nothing, it failed to address how the brake system was intended to operate.

After a bit of investigation, reading up on the various Honda linked brake methodologies, and some reverse engineering of the brake system components of the ST1300, and GL1800, I developed this schematic.

You are more than welcome to download the drawing, and use it as you see fit. As this drawing is a work in progress, I'd be obliged if you point out any errors that you discover.

Cheers, Anna'sDad
 
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