How is the pedal, firm or spongy?
Gonna try to install one of my 2x new SMC units...
- Thread starter The Dark Shadow
- Start date
How is the pedal, firm or spongy?
jfheath
John Heath
Yeah - As I said before, it can get to you.
Vaccuum pumps - I like to use them to pull the fluid through, and to go round flexing the hoses and tapping the joints to dislodge the air bubbles while it is sucking the fluid through. Its like having an extra pair of hands. And you get a bit of exercise trying to get back to the bleed valve before the reservoir empties itself !
BUT - vacuum pumps are pretty useless at getting the last bit of air out and making the brakes feel nice and firm. The reason is that they suck air past the threads of the bleed valves, so you can never tell if it is air coming out, or air being sucked in.
So having got the system filled and most big air gaps purged fromt he system and with some feeling at the lever, I will use the non retunr bleed tube and go round the cycle 2 or three times chasing the imaginary air bubbles round to the next bleed valve. Tapping, flexing. And then suddenly just after a tiny little bubble is spat out into the tube, the pedal is firm.
So I use vaccuum pump for filling, non return bleed tubes for bleeding.
OP
OP
There is zero pressure in the back brake, other than the spring. Zero hydraulic pressure. Zero.
OP
OP
Can you use the vacuum pump with a one way valve inline...? Seems logical to me but I don't know $h1t about this stuff as you can see. It is NOT an easy task and I wish no one had even said that.
OP
OP
A super quick update...
I tried a bit more bleeding with the vacuum, since John mentioned he uses the vacuum to fill the lines, then a one-way valve to purge the air.
So, there is NOTHING coming from the proportional valve, nor the front left (centre) bleeder.
The right front center was showing brake juice coming through - no bubbles.
The two rear bleeders were showing a bit of juice coming through but mostly air.
I can't help but wondering if there is foreign material (gunk, junk, cr@p) in the lines somewhere, preventing fluid from flowing.
That's my best guess...
And if so, then it means pulling the hydraulic system apart piece by piece to trouble shoot and find the blockage.
If this is the case, my "Holy Grail" of bikes is turning into the "Holy Hand-grenade".
One, two, four...
Three, Sir! Three...!!
Thanks for all your efforts to help.
I tried a bit more bleeding with the vacuum, since John mentioned he uses the vacuum to fill the lines, then a one-way valve to purge the air.
So, there is NOTHING coming from the proportional valve, nor the front left (centre) bleeder.
The right front center was showing brake juice coming through - no bubbles.
The two rear bleeders were showing a bit of juice coming through but mostly air.
I can't help but wondering if there is foreign material (gunk, junk, cr@p) in the lines somewhere, preventing fluid from flowing.
That's my best guess...
And if so, then it means pulling the hydraulic system apart piece by piece to trouble shoot and find the blockage.
If this is the case, my "Holy Grail" of bikes is turning into the "Holy Hand-grenade".
One, two, four...
Three, Sir! Three...!!
Thanks for all your efforts to help.
I'm in the middle of a job, so I'll try and make these comments short, and to the point...
Your super quick update post, sounds like you are jumping all over the place (not correct sequence) which confuses me because when we were talking, you said you were following me to the letter in the right sequence?
When bleeding air from the system, you DON'T move on to the next bleeder until you are completely finished with the current one etc.
You indicate NOTHING from the PCV...Nor the front left center, which are nowhere near each other in the correct sequence etc.
Your post makes it sound like you are jumping all over the place.
Here is what "I" would suggest you do, and in what order "I" would do it in etc.:
Put the vacuum on the shelf and do NOT try to use it.
Start at the very BEGINING, I know you don't want to do the front again, but again, this is what I would do.
Fill up the Handlebar master cylinder, place a 3/16ID x 5/16OD clear tube over the left upper bleeder, open the bleeder and WAIT for gravity to allow the fluid to start dripping out, then use your once way check valve (make sure the arrow is pointing in the correct direction, from the bleeder to the catch bottle) then bleed that (1) bleeder.
Next, do the same with the upper right bleeder.
Top off the fluid in the handlebar M/C and close it up.
Next, remove the SMC, place it in the correct position (with a shim between the pads) and place your HOSE on the PCV nipple, open it up and slowly press/pump the rear pedal until fluid flows through this nipple (foot pedal/rear MC housing) you MUST use the foot lever to push the fluid through this circuit, don't be in a hurry, and don't move on until its flowing correctly.
Exercise the SMC piston a few times and alternate it between the foot pedal (read John's article again)
Next do the same with the forward/rear bleeder, (closest to the engine) Again do not move on until it is finished.
Next move to the right front lower bleeder....same thing, gravity/hose only, then use your check valve and finish the bleed on that nipple.
Next move to the left front lower bleeder....you guessed it, same thing! Don't be in a hurry etc.
Last bleeder, is the furthest to the rear on the swingarm....same thing! Don't be in a hurry etc.
***Do NOT use your Vacuum to do this*** use your check valve and clear tubing (old school) by hand pressure, using the levers.
IF, at this point, you still don't have ANY pressure on the rear pedal, I would start pressurizing the system with the correct levers, and cracking open the banjo fittings until fluid weeps out, then tighten them back down.
Strap your levers, and use your stick (good idea by the way) and let it sit OVER NIGHT.
Do not get in a hurry and release the pressure until the next morning.
Let us know how this turns out.
Good luck.
Larry
Your super quick update post, sounds like you are jumping all over the place (not correct sequence) which confuses me because when we were talking, you said you were following me to the letter in the right sequence?
When bleeding air from the system, you DON'T move on to the next bleeder until you are completely finished with the current one etc.
You indicate NOTHING from the PCV...Nor the front left center, which are nowhere near each other in the correct sequence etc.
Your post makes it sound like you are jumping all over the place.
Here is what "I" would suggest you do, and in what order "I" would do it in etc.:
Put the vacuum on the shelf and do NOT try to use it.
Start at the very BEGINING, I know you don't want to do the front again, but again, this is what I would do.
Fill up the Handlebar master cylinder, place a 3/16ID x 5/16OD clear tube over the left upper bleeder, open the bleeder and WAIT for gravity to allow the fluid to start dripping out, then use your once way check valve (make sure the arrow is pointing in the correct direction, from the bleeder to the catch bottle) then bleed that (1) bleeder.
Next, do the same with the upper right bleeder.
Top off the fluid in the handlebar M/C and close it up.
Next, remove the SMC, place it in the correct position (with a shim between the pads) and place your HOSE on the PCV nipple, open it up and slowly press/pump the rear pedal until fluid flows through this nipple (foot pedal/rear MC housing) you MUST use the foot lever to push the fluid through this circuit, don't be in a hurry, and don't move on until its flowing correctly.
Exercise the SMC piston a few times and alternate it between the foot pedal (read John's article again)
Next do the same with the forward/rear bleeder, (closest to the engine) Again do not move on until it is finished.
Next move to the right front lower bleeder....same thing, gravity/hose only, then use your check valve and finish the bleed on that nipple.
Next move to the left front lower bleeder....you guessed it, same thing! Don't be in a hurry etc.
Last bleeder, is the furthest to the rear on the swingarm....same thing! Don't be in a hurry etc.
***Do NOT use your Vacuum to do this*** use your check valve and clear tubing (old school) by hand pressure, using the levers.
IF, at this point, you still don't have ANY pressure on the rear pedal, I would start pressurizing the system with the correct levers, and cracking open the banjo fittings until fluid weeps out, then tighten them back down.
Strap your levers, and use your stick (good idea by the way) and let it sit OVER NIGHT.
Do not get in a hurry and release the pressure until the next morning.
Let us know how this turns out.
Good luck.
Larry
So you have air in the lines.
How much fluid left in the rear reservoir? Letting it go empty at any point during the procedure will kill the job.
And make sure that at each step the bleeder is tight before disconnecting the tube and one way valve.
As mentioned by previous posters, do not use the vacuum pump, the most it can generate to get the fluid in motion is 15 psi, the pedal can do much more and you may need it to displace old gunk,
And congratulations, you get extra points for understanding already that step 1 and 2 (front brakes) are not necessary when you chase air in the lines served by the rear reservoir. Well done!
You may need to get more fluid by now!
OP
OP
Since nothing was working, "doing the same thing over and over expecting different results is the definition of insanity". 6 times, no good result. Trying the PCV, there was nothing. So I tried other bleeders to see if there was anything at all.
I tried the PCV valve 5 times today... NOTHING! The pressure on the vacuum holds still... Hence, I'm wondering if there's foreign debris blocking the circuit somewhere...
But I don't know much of anything... All I can do is try whatever I can think of...
I did the front circuit at least 3 times, and the brake lever functions as one would expect good brakes to function.
Rear reservoir is full and will no longer go down in level.
I definitely tighten the bleeders properly.
I'm getting 2x one way valves arriving Friday (likely).
I wonder what the brake pedal can do since it has zero pressure and there's zero coming out of PCV even after using the brake pedal literally dozens of times, alternating with plunging the SMC...
Honda maintenance is a breeze... lol
****important question *****
Trying to think outside the box, on why your having such difficulties with the brakes, I remembered a while back, another member was having a very similar experience with his brakes etc.
Some IDIOT decided to bypass his linked braking system, or at least thought he was, and didn’t bother telling the new owner he sold the bike too….
Your bike does not have anything like this does it?
Just grasping at straws, but it’s worth checking.
The line was pulled and capped, and the fitting was plugged etc.
Trying to think outside the box, on why your having such difficulties with the brakes, I remembered a while back, another member was having a very similar experience with his brakes etc.
Some IDIOT decided to bypass his linked braking system, or at least thought he was, and didn’t bother telling the new owner he sold the bike too….
Your bike does not have anything like this does it?
Just grasping at straws, but it’s worth checking.
The line was pulled and capped, and the fitting was plugged etc.
Attachments
Last edited:
OP
OP
Nope. It's good to explore all options. But that's not the issue.
I just dunno wth I'm doing... or there's a blockage.
Take a picture of your PCV for us, maybe we'll see something that stands out, that you wouldn't know to look for.
The picture I posted clearly shows the line removed, capped, and hole plugged.
Are you sure nobody did that to yours?
It would sure explain why your having such trouble.
The picture I posted clearly shows the line removed, capped, and hole plugged.
Are you sure nobody did that to yours?
It would sure explain why your having such trouble.
Could be your rear MC is toast as well.
The shortest run is from the MC to the center rear, if you pump up the pedal and get nothing at the center rear, MC might need work,
OP
OP
So, question... The reservoir is DIFFERENT than the master cylinder, yes...?
sirbike
Site Supporter
The the reservoir sits above the rear master cylinder. A hose connects the reservoir to the mc.
Effectively not different, you could say two parts of the same unit.
It’s hard to imagine that the mc has failed on a 2014.
If no joy after the bleed check valves, I would consider taking out the mc. Pumping the mc with thumb over the port for the hose to check for pressure.
To be sure, did you once get fluid pumping out of the first bleeder in the sequence, and now you don’t?
Effectively not different, you could say two parts of the same unit.
It’s hard to imagine that the mc has failed on a 2014.
If no joy after the bleed check valves, I would consider taking out the mc. Pumping the mc with thumb over the port for the hose to check for pressure.
To be sure, did you once get fluid pumping out of the first bleeder in the sequence, and now you don’t?
Just in case this is the cause..
There are 2 reservoirs.
One for the front and one for the rear.
Front is by the front brake lever. Rear is above the rear brake pedal.
Follow the tube up....
There are 2 reservoirs.
One for the front and one for the rear.
Front is by the front brake lever. Rear is above the rear brake pedal.
Follow the tube up....
OP
OP
One of the members messaged me recommending to pump the brake lots and hold it down while using a vacuum on the PCV, only opening the bleeder while holding down the pedal, and only opening the bleeder a short time to let some bubbles escape. Every 3rd or 4th cycle, squeeze the SMC.
I did this for 3.5 hours!!! 2 to 3 dozen cycles...
NOTE: The vacuum tool is confirmed to work 100%. Do NOT question this! It is CONFIRMED TO WORK!
I tried this process with the bike in 3 orientations...
1: nose high
2: level
3: nose low
Nose high - The vacuum was seeming to suck a nominal touch of fluid (1/2 inch) into the tube, and this is handy because I could see the air getting sucked through it.
I was able to confirm that the bubble rate changed when the pedal was held to the floor, vs released. Also, when the pedal was held to the floor (with a stick) and at the same time I plunged the SMC, you could see the bubble rate change. (This confirms that the process was working at least somewhat!)
But, after 3.5 hours of doing this with nothing more than similar bubbles, I tried putting the bike level, then nose down (I have a sloped driveway), but now there is NOTHING coming through the vacuum tube at all.
I can't help but think there's some foreign material causing a clog in the lines somewhere, and at times it becomes dislodged, and at times it clogs.
I truly CANNOT BELIEVE that this process should take 3.5 hours of pump/suck pump/suck ad infinitum.
SOMETHING IS WRONG!!
My best bet is there's a loose bit of foreign material in the lines. If this is the case, I give up...
Seriously, this is a disaster!
I need someone here who can help. I'm close to 17 hours into this already!
Since I'm not getting any result as is, I cannot imagine that the problem will be resolved by one way check valves (although I can understand their value).
Something is wrong, don't you think...?
I'm not stupid, and I'm doing things as their supposed to be done...
I mean, for chrissake, I think the service manual even says to use a vacuum tool...
There's gotta be a reason why I'm getting intermittent results from the PCV, and my best guess is that this is the core of the problem.
I did this for 3.5 hours!!! 2 to 3 dozen cycles...
NOTE: The vacuum tool is confirmed to work 100%. Do NOT question this! It is CONFIRMED TO WORK!
I tried this process with the bike in 3 orientations...
1: nose high
2: level
3: nose low
Nose high - The vacuum was seeming to suck a nominal touch of fluid (1/2 inch) into the tube, and this is handy because I could see the air getting sucked through it.
I was able to confirm that the bubble rate changed when the pedal was held to the floor, vs released. Also, when the pedal was held to the floor (with a stick) and at the same time I plunged the SMC, you could see the bubble rate change. (This confirms that the process was working at least somewhat!)
But, after 3.5 hours of doing this with nothing more than similar bubbles, I tried putting the bike level, then nose down (I have a sloped driveway), but now there is NOTHING coming through the vacuum tube at all.
I can't help but think there's some foreign material causing a clog in the lines somewhere, and at times it becomes dislodged, and at times it clogs.
I truly CANNOT BELIEVE that this process should take 3.5 hours of pump/suck pump/suck ad infinitum.
SOMETHING IS WRONG!!
My best bet is there's a loose bit of foreign material in the lines. If this is the case, I give up...
Seriously, this is a disaster!
I need someone here who can help. I'm close to 17 hours into this already!
Since I'm not getting any result as is, I cannot imagine that the problem will be resolved by one way check valves (although I can understand their value).
Something is wrong, don't you think...?
I'm not stupid, and I'm doing things as their supposed to be done...
I mean, for chrissake, I think the service manual even says to use a vacuum tool...
There's gotta be a reason why I'm getting intermittent results from the PCV, and my best guess is that this is the core of the problem.
From what TDS is reporting, there is no flow with pedal action, the check valve would have no flow to check either.
Or maybe first a quick try pumping through the step 4 center rear bleeder, the shortest run to a bleeder and least likely to be obstructed.
The reservoir feeds the Master Cylinder. The Master Cylinder is really not much more than a little pump, not unlike the pump for your bicycle, except it pumps oil out of the reservoir into the brake system instead of air like on your bicycle..
If you press the pedal with a bleeder open and the fluid in the reservoir is not going down, there is blockage somewhere right at the MC (if the blockage was in the line, the pedal would be hard to press as it builds up pressure against the blockage, just as you have to pump up your bicycle harder for higher pressure in the tire).
The Step 4 run is the shortest run from pump to bleeder. If you crack open the rear middle bleeder and nothing comes out when pumping the pedal, then it might help to take a closer look at the rear MC. Simple enough test to do.
No, the service manual states something like "If you use a vacuum, follow their instructions". It does not tell you to Use a vacuum.
This system can be bled manually with just a hose, 8 mm wrench, and a catch bottle, by using the levers.
But....best would be to follow what Larry and several others have advised.
Yes, the pump is working, but it is just not the tool you need at this stage with the issues you are reporting. Sure, the manual says you can use a vacuum pump, but they are not covering the troubleshooting mode you are in right now.
Larry has probabkly bled over thousand STs and could write a manual about all that is better left alone in the manual.
This is a good observation. Your rear MC may not be clogged after all.
The lines are no "aligned". The short run to 4 is separate and unlikely to be clogged. That's why it could be worth a quick test.
Crack this bleeder and keep pumping the pedal (NO VACUUM PUMPING). And observe if the fluid in the reservoir is going down or not.
