2003 ST1300ABS- can't get PCV circuit to bleed

HOS

Joined
Jan 5, 2019
Messages
33
Age
67
Location
texas
Had bike about a year and rear brake peddle was always soft and had too much travel, but did work. A couple of weeks a ago I bleed system but didn't bleed the SMC. On first ride rear peddle perfect. 2nd ride a week later no rear peddle at all-zero. So started over and followed the proper sequence. Removed SMC and elevated to 15degrees, at PCV I could not get a continual flow of fluid. It flowed a few seconds but had a lot of air, level in rear reservoir dropped as expected. Then it just stopped, will hold constant vacuum with bleed nipple open. Went to front right caliper center nipple and it free flows air, can't build vacuum. As anyone seen anything like this before? It seems like maybe the PCV is stuck or there is a leak due to a ruptured hose or something?
 
Free flows sure sounds like you have air coming through the bleed nipple threads. Try 2 wraps of Teflon tape or permatex high temp thread sealer that i just learned about from Igofar.
 
Read this It may help.

Article [13] - ST1300 - Brake Maintenance - Getting all the air out of the brake system | ST1300 Articles

A detailed look at the process of getting the air out of the Honda ST1300 brake lines. A sequence of diagrams of the brake circuits, colour coded to show which parts of the system are being accessed when each bleed valve is opened and explanations of where the trouble spots are. These are just...
www.st-owners.com www.st-owners.com

Teflon tape is a must if you are using a vacuum pump, but you will still get air leaking past the threads and putting air in the vacuum tube. That doesn't mean there is air in the system though. Typically air being sucked past the threads is a constant stream. Air from the lines comes through in irregular sized bubbles. Use the vacuum while pumping the break pedal and/or the Smc.

Finish off with a one way valve, rather than the vacuum pump. Motion Pro seems to be the make of choice in the USA.

It will take a few circuits of the 5 valves to clear the rear lines.
 
Last edited:
HOS said:
Had bike about a year and rear brake peddle was always soft and had too much travel, but did work. A couple of weeks a ago I bleed system but didn't bleed the SMC. On first ride rear peddle perfect. 2nd ride a week later no rear peddle at all-zero. So started over and followed the proper sequence. Removed SMC and elevated to 15degrees, at PCV I could not get a continual flow of fluid. It flowed a few seconds but had a lot of air, level in rear reservoir dropped as expected. Then it just stopped, will hold constant vacuum with bleed nipple open. Went to front right caliper center nipple and it free flows air, can't build vacuum. As anyone seen anything like this before? It seems like maybe the PCV is stuck or there is a leak due to a ruptured hose or something?
Click to expand...
DO NOT use a vacuum for bleeding the PCV. You must use the foot pedal to push the fluid through and open the passage. No amount of air pressure will work.
Use a motion pro hydraulic bleeder ($13 dollars on Amazon) or just do it the old fashion way with a loop in the line, while opening and closing the bleeder.
As you found out, you MUST follow the procedure or you'll introduce and move a lot of air in the system.
If you have any questions, PM me a contact phone number and I'll see if I can get you pointed in the right direction and sorted out.
Igofar
 
Try pumping the pedal to help the vacuum pump along or just pump the pedal and dispense with the vacuum pump altogether. That is a long circuit and if air is leaking in from the threads or from the kit's adapter to fit the hose to the bleeder it may be impossible to pull sufficient vacuum.
 
Igofar said:
DO NOT use a vacuum for bleeding the PCV. You must use the foot pedal to push the fluid through and open the passage. No amount of air pressure will work.
Use a motion pro hydraulic bleeder ($13 dollars on Amazon) or just do it the old fashion way with a loop in the line, while opening and closing the bleeder.
As you found out, you MUST follow the procedure or you'll introduce and move a lot of air in the system.
If you have any questions, PM me a contact phone number and I'll see if I can get you pointed in the right direction and sorted out.
Igofar
Click to expand...

I was about to post the same thing. I could never get more than a dribble (if that) trying to vacuum bleed the PCV. Using the rear brake pedal works very well and is convenient since both it and the PCV are on the right side together. Just do the old fashioned pump, hold, open bleeder, close bleeder, release pedal and repeat. No need for any vacuum assist.
 
First, big thanks to everyone. I now know more about bleeding a system than I knew existed. I used the one-way valve and rear peddle and had great results on first test drive. I left off the tupperware and left the handle and peddle depressed. I had my wife hold them and didn't tell her I wouldn't be back till tomorrow....just kidding.
 
Test Drive # 2: The Eagle has Landed, yes we have full braking, leaving the handle and foot peddle compressed all night had a big impact, both are very responsive with minimal travel. I don't have anything to compare to, having never ridden another ST1300, but the breaks seem to perform perfectly. So much better than any time before. You can really feel the effect of the linked system when you apply the rear brake only( just to test it out). Very pleased and again thanks to all the great support from Team-ST.
 
I thought I remember reading the right side tupperware doesn't have to be removed to bleed this, is that true? Any tips?
 
Whooshka said:
I thought I remember reading the right side tupperware doesn't have to be removed to bleed this, is that true? Any tips?
Click to expand...
I saw a post where they said they raised the tank and was able to reach the PCV, I did not try but would not be surprised if it's possible. Once you take the fairing off one time it is really not that big of a deal. It takes 45min if you really go slow, could probably do in half that time if you needed to.
 
HOS said:
Test Drive # 2: The Eagle has Landed, yes we have full braking, leaving the handle and foot peddle compressed all night had a big impact, both are very responsive with minimal travel. I don't have anything to compare to, having never ridden another ST1300, but the breaks seem to perform perfectly. So much better than any time before. You can really feel the effect of the linked system when you apply the rear brake only( just to test it out). Very pleased and again thanks to all the great support from Team-ST.
Click to expand...
Now before you start doing your happy dance, do the safety function test on your SMC to make sure your brakes are working correctly, and releasing correctly.
If you keep your brake lever out at the furthest position from the grip, you will be able to control the brakes better.
 
Whooshka said:
I thought I remember reading the right side tupperware doesn't have to be removed to bleed this, is that true? Any tips?
Click to expand...
You remember correctly. If you are only doing a brake fluid service and not the coolant and valves you can bleed the PCV with the right side middle cowl mostly in place. To get to it I first remove the plastic rivet down low on the lower back edge of the cowl - it's kind of directly above the brake pedal, then remove 5 bolts holding the right side black lower cowl in place. Disengage the middle cowl's tab that fits into the lower cowl just below where the rivet was and pull the lower cowl free and allow it to droop down. You can leave the left side lower cowl in place, the right side one will just drop down and hang there. Now pop off the tip-over wing sacrificial cover and remove the two 8 mm bolts under the cover. Watch out for the rubber bushings and collars so they don't fall out of the cowl and get lost. The last fastener is the long flanged shoulder bolt in the recess just above the valve cover. With all these out, gently pull the lower back edge of the cowl away from the bike. There is a locating pin on the cowl that fits in a rubber bushing in the frame - it's a press fit and it will pop out and the the rear of the cowl is free and the cowl is only retained by the screws and rivets up front in front of the fairing pocket cover and screws under the mirror housing. You can pull the middle cowl out an inch or three and access the PCV bleeder. I had a piece of wood about 2" x 2" that I would gently wedge in place to hold the gap open.
 
Igofar said:
I'm your huckleberry :WCP1:
Click to expand...

Thank you sir. i just may call you tonight.

dduelin said:
You remember correctly. If you are only doing a brake fluid service and not the coolant and valves you can bleed the PCV with the right side middle cowl mostly in place. To get to it I first remove the plastic rivet down low on the lower back edge of the cowl - it's kind of directly above the brake pedal, then remove 5 bolts holding the right side black lower cowl in place. Disengage the middle cowl's tab that fits into the lower cowl just below where the rivet was and pull the lower cowl free and allow it to droop down. You can leave the left side lower cowl in place, the right side one will just drop down and hang there. Now pop off the tip-over wing sacrificial cover and remove the two 8 mm bolts under the cover. Watch out for the rubber bushings and collars so they don't fall out of the cowl and get lost. The last fastener is the long flanged shoulder bolt in the recess just above the valve cover. With all these out, gently pull the lower back edge of the cowl away from the bike. There is a locating pin on the cowl that fits in a rubber bushing in the frame - it's a press fit and it will pop out and the the rear of the cowl is free and the cowl is only retained by the screws and rivets up front in front of the fairing pocket cover and screws under the mirror housing. You can pull the middle cowl out an inch or three and access the PCV bleeder. I had a piece of wood about 2" x 2" that I would gently wedge in place to hold the gap open.
Click to expand...

Thanks for the details. I'm no stranger to removing the plastic. I've removed it a half dozen times, but short cuts help. Last time I did a bleed all the plastic was off. That was almost 3 years ago and although my brakes are performing fine I figured I was due.
 
Whooshka said:
Thank you sir. i just may call you tonight.



Thanks for the details. I'm no stranger to removing the plastic. I've removed it a half dozen times, but short cuts help. Last time I did a bleed all the plastic was off. That was almost 3 years ago and although my brakes are performing fine I figured I was due.
Click to expand...
‘Welcome. When I was on an ST I was doing a flush every 12,000 or once or twice a year so the short cut was meaningful. I think I learned it from Larry.
 
Whooshka said:
I thought I remember reading the right side tupperware doesn't have to be removed to bleed this, is that true? Any tips?
Click to expand...

I've seen where someone was able to flex the faring out enough to reach the bleeder but you risk cracking the faring or spilling brake fluid on it and damaging the paint. I would recommend removing the panel and getting it safely out of the way.
 
Igofar said:
Now before you start doing your happy dance, do the safety function test on your SMC to make sure your brakes are working correctly and releasing correctly.
If you keep your brake lever out at the furthest position from the grip, you will be able to control the brakes better.
Click to expand...
Took it a few times around and all is working well. I am really very impressed with the system now that it is fully functional.
 
You must log in or register to reply here.
Back
Top Bottom