Brake Bleeding Issue with Proportioning Control Valve

ckbmunch

ckbmunch

Joined
Jan 22, 2023
Messages
15
Age
56
Location
CT
Going through to change out the old brake fluid on my 2005 ST1300 non-abs. Following the manual directions was going fine right up to the part where I went to bleed the PCV and got no fluid through the PCV bleeder screw despite backing it well off.
I’m using a manual vacuum/pressure bleeder tool that is holding vacuum and worked well with all bleeder valves in sequence both before and after the PVC step.
I drained both front and rear master cylinders just short of running dry and kept filling with fresh DOT4 fluid. I did let the fluid get low in the rear master cylinder just once and allowed a bit of air in and then flushed multiple containers worth of new fluid to try and make sure all air was bled out.
Looking to the collective mind for suggestions.
 
I take it you have gotten nothing yet out of the bleeder on the PCV? The PCV has a very long circuit and goes through both the delay valve and the SMC and it gets very hot all the time because it's location on the frame above the engine. I have seen the fluid in PCVs turn turn thick and gel-like. A hobbyist vacuum pump might need help initiating or moving fluid. When I did the PCV I pumped the pedal to help the pump out. Put a vacuum on it then manually pump the foot pedal to flush it. I am a service manual fanboy but take a look at this pdf and just make sure you followed good practices in the right sequence. The SM is not the best at explaining the what and why.
 

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  • ST1300_hydraulic_flush.pdf
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dduelin said:
I take it you have gotten nothing yet out of the bleeder on the PCV? The PCV has a very long circuit and goes through both the delay valve and the SMC and it gets very hot all the time because it's location on the frame above the engine. I have seen the fluid in PCVs turn turn thick and gel-like. A hobbyist vacuum pump might need help initiating or moving fluid. When I did the PCV I pumped the pedal to help the pump out. Put a vacuum on it then manually pump the foot pedal to flush it. I am a service manual fanboy but take a look at this pdf and just make sure you followed good practices in the right sequence. The SM is not the best at explaining the what and why.
Click to expand...

Great reply… SUCCESS !!! Combining the pedal pressure with the manual bleeder finally cleared it. I did see some small particles in this pvc bleed and darker fluid than the other bleed points so I think your higher temp scenario might have been the difference. Thanks for everyone’s help. Great forum.
 
ckbmunch said:
Great reply… SUCCESS !!! Combining the pedal pressure with the manual bleeder finally cleared it. I did see some small particles in this pvc bleed and darker fluid than the other bleed points so I think your higher temp scenario might have been the difference. Thanks for everyone’s help. Great forum.
Click to expand...
Great to hear it went well.

But call Igofar anyway. He'll talk your ear off but he's ST-O's best hands-on resource.
 
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