Bled The Clutch, But No Pressure In Lever Or At Slave Cylinder. 1993

[BRad704]

Went to ride this morning and the clutch would BARELY let me get it in gear, but the bike began rolling and finally no more clutch pressure. Back into the carport...

Clutch master cyl was totally dry, went and got DOT4 brake fluid and just went through a bleeding operation on clutch.

Fill reservoir

Squeeze clutch lever

Open bleeder on Slave

Close Bleeder on Slave

Release clutch lever

check reservoir level (refill as needed)

REPEAT.

Is that right? Because I have flushed all the old fluid out of the system and now get clear fluid from the bleeder. But I still have zero pressure building up in the clutch lever.

Notes:

Made sure reservoir was never low/empty

Noticed that after waiting 10-15 seconds between one session and REPEAT, there was a much stronger "flush" when opening the bleeder

Reservoir level did go down slowly, so I know I was pushing fluid into the lines.

Any idea or experience on what's still wrong?

I just read this on the "other" vfr forum...

- When you rebuild your slave and the system will be "dry" again. Sometimes if you fool with a dry M/C and pull the lever all the way back before refilling the piston seal will ketch an edge of the port of the fluid path and flip the seal backward. (SOB!) After that no matter how many pumps - you wont get pressure. You got fluid on both sides of the piston! The only fix after that is to drain it and disassemble and flip the seal back in the correct direction. - To avoid, pull the lever back only about half way till you get going with some pressure first. - Lesson learned - dont pull lever back to the handlebar on a dry M/C.

[superfunkomatic]

I used a Mity Vac to push the fluid through. Then I cracked open the banjo bolt on the reservoir at the handlebars each time I pushed pressure in with the lever. After about 10 pushes it created pressure in the line - never did use the bleeder valve at the bottom of the lines.

[BRad704]

Well right now I know there if solid fluid from the res to the slave/bleeder. I'm not sure what to check next and don't have a handheld bleeding vac.

I may try tearing into the master cyl and see if that seal is flipped over, as mentioned in the black highlights above...

[Guest]

HI -- I just did this last night too with the same result - No pressure in the master cylinder leaver. I had accidently let all the fluid out of the reservoir while bleeding the clutch. I read online all this dry bleeding how to's and thought I was in for a long night. I did notice micro bubbles rising from the reservoir. So I decided to start pumping the leaver. I started to see larger bubbles appear and pressure to slowly build. I tapped (gentle) the brake hose nut where it meets the reservoir and noticed I could get some bubbles out as I kept pumping. In about 15 minutes of pumping I had my clutch back to what it was. :)

Give it a try. Beats other methods if it works for you....

[Burns]

if that thing was working before, and now it isn't since running dry, the seal isn't flipped. You still most likely have air in the line.

I know what usually works for me if I don't have a minivac...

put a length of clear hose on bleeder valve.

fill res.

pull in lever, while holding, crack open bleeder, then close again. release lever

repeat. repeat repeat.

eventually you should start seeing fluid in the hose.. keep doing proceedure till you don't see bubbles.

if that's not working, a rebuild might be in order, as sometimes the return hole in the mast cyl plunger gets plugged up, seals dry up, and whatnot.

[BRad704]

Burns, I used your method (except without the tubing). I just crammed towels around the bleeder and changed them before anything ran onto the lower fairing.

I just checked again and I am getting good, clear fluid from the bleeder with no bubble at all.

Loosened the upper banjo and gave a slow squeeze. got a pretty good squirt of fluid, retightened banjo. I think the MC is getting a good push into the line.

I now think it is just more air up higher in the line. I'll try tapping the lines in between cycles of pumping/bleeding because right now I'm getting 0 air bubbles coming back out the master cylinder.

[2thdr]

Isn't this another case of the problem with the hydraulic systems on Honda bikes that there is not a bleeder valve at the top of the system where the air would be easiest to remove?

Disclaimer: This statement is made by a mechancal midget.

[BRad704]

Don't you bleed car brakes the same way? from the caliper down at the bottom of the system.

I'm pretty baffled right now. the fluid HAS to be going somewhere, but it squirts out the upper banjo, so i know there's master cylinder action, it squirts out the lower banjo, so i know there's fluid in the line, and it comes out of the bleeder when I pull clutch and open the bleeder under pressure.

[FJ12Ryder]

Seems to me if you didn't drain the clutch master cylinder on purpose, but just found it empty after the clutch quit working you have a leak. You'll probably need to find and fix the leak before you can get any pressure to build. Or did I miss something? If you have a leak, my suggestion would be to look at the slave cylinder seal. Good luck.

[Burns]

have you unbolted the slave from the engine case and checked the piston? see if it's wet, or if it moves when you squeeze lever?

[SamW]

I had this issue with a couple of mine, try taking the master off the bar and hold it so the line is straight up and the MC is the highest point, then give is a few squeezes (a little harder to do without being mounted on the bar). But if you are low or out a fluid, I would guess your slave needs a rebuild or replaced, not too uncommon for the slave to fail on a VFR.

[BRad704]

Seems to me if you didn't drain the clutch master cylinder on purpose, but just found it empty after the clutch quit working you have a leak. You'll probably need to find and fix the leak before you can get any pressure to build. Or did I miss something? If you have a leak, my suggestion would be to look at the slave cylinder seal. Good luck.

That's what I'm thinking too...

have you unbolted the slave from the engine case and checked the piston? see if it's wet, or if it moves when you squeeze lever?

was JUST trying this, but only have the 8mm from the toolkit, and the bolts are tighter than that little wrench can handle. :( will have to get tools from the shop later.

[V-FORE]

one other thing to look at pull cover off reservoir soak up drain fluid, their is a tiny hole the fluid goes through that gets plugged, clean out then replace fluid then try, this stumped me once

good luck

[superfunkomatic]

I had to use quite a bit of fluid to push the air out of the lines by loosening the top banjo bolt - but eventually it worked. Probably a litre and a half.

Burns, I used your method (except without the tubing). I just crammed towels around the bleeder and changed them before anything ran onto the lower fairing.

I just checked again and I am getting good, clear fluid from the bleeder with no bubble at all.

Loosened the upper banjo and gave a slow squeeze. got a pretty good squirt of fluid, retightened banjo. I think the MC is getting a good push into the line.

I now think it is just more air up higher in the line. I'll try tapping the lines in between cycles of pumping/bleeding because right now I'm getting 0 air bubbles coming back out the master cylinder.

[Duc2V4]

I would look at picking up one of these, it's basically an "in-line" speed bleeder. Take this and and an empty water bottle to catch the fluid and so you can look at the hose as the fluid comes out. Sometimes even after you see clear fluid flowing you can still see bubbles after pumping for a while. A Mity-vac works best when trying to clear or refill the line, but those will run $30-$40. This is about half the price and will make things much quicker and easier IMO.

http://www.cyclegear.com/CycleGear/Accessories/Tools/Other-Tools/brand/STOCKTON%20TOOL%20COMPANY/Brake-Bleeder-Tool/p/36529_00000

[The Phantom]

Fill reservoir

Squeeze clutch lever

Open bleeder on Slave

Close Bleeder on Slave

Release clutch lever

check reservoir level (refill as needed)

REPEAT.

I think a better technique is:

Fill reservoir

Pump lever 4-5 times

Open bleeder

Slowly pull lever towards bar

Close bleeder BEFORE lever gets to full travel but while it is still moving

Pump lever 4-5 times

repeat

Even if there are issues elsewhere in the system, this technique should see you get feel at the lever after two or three goes.

It is always worth checking the slave piston, crud in the system can cause it to bind and not have full travel in one or both directions.

[BRad704]

I would look at picking up one of these, it's basically an "in-line" speed bleeder. Take this and and an empty water bottle to catch the fluid and so you can look at the hose as the fluid comes out. Sometimes even after you see clear fluid flowing you can still see bubbles after pumping for a while. A Mity-vac works best when trying to clear or refill the line, but those will run $30-$40. This is about half the price and will make things much quicker and easier IMO.

http://www.cyclegear.com/CycleGear/Accessories/Tools/Other-Tools/brand/STOCKTON%20TOOL%20COMPANY/Brake-Bleeder-Tool/p/36529_00000

So with this, I just won't have to open/close the bleeder after ever squeeze, right? Once the air is purged from the clear tube and check valve, I should have a solid (air-free) line, so I can pump until I get no more bubbles.

The idea of "building pressure" is odd to me. Fluid is non-compressible, so it if there are no leaks, and solid fluid between MC piston and SC slide, then I should have instant pressure. I really think the slave cylinder is leaking, but i have not gotten it off yet to verify.

[YoshiHNS]

Ah, but you see, fluids ARE compressible. It just takes a lot of force to do it. Most people are taught that they aren't just to make the math easier. I mean, who wants to learn the actual facts and truths nowadays. (Hot air balloons were used in the Civil war, never learned that in grade school did ya).

http://xkcd.com/669/

Air can still get trapped in a crevice in the system. Just because you're pumping fluid through doesn't mean you are pushing all the air out with it. Still good practice to tap the lines and move things about to help any air escape upward.

[BRad704]

Fair enough. But they not compressible to the point I am experiencing.

As an engineering major, I can certainly appreciate the comic too. Lol.

At this point, once I get the slave cyl off, I should see 1 of 2 things. Either zero movement in the slide, meaning air in the line. Or fluid escaping around the slide, meaning it needs a rebuild.

Sent from my handheld-sending-thing...

[FJ12Ryder]

In the most practical sense fluids are incompressible. The pressure necessary to compress a fluid a noticeable amount is way beyond the reach of most mortal men. Which of course is why hydraulic systems work. If fluids were compressible under normal circumstances, they wouldn't work.

And I was taught about the balloons as experimental observation posts during the Civil War, but they actually were hydrogen gas balloons, not hot air balloons. Of course it was taught as recent history when I was in school.

[Burns]

ok Yoshi... don't be harshing our groove here. LOL.. the man needs a clutch (well, at least for starting and stopping purposes)!

[Duc2V4]

I would look at picking up one of these, it's basically an "in-line" speed bleeder. Take this and and an empty water bottle to catch the fluid and so you can look at the hose as the fluid comes out. Sometimes even after you see clear fluid flowing you can still see bubbles after pumping for a while. A Mity-vac works best when trying to clear or refill the line, but those will run $30-$40. This is about half the price and will make things much quicker and easier IMO.

http://www.cyclegear.com/CycleGear/Accessories/Tools/Other-Tools/brand/STOCKTON TOOL COMPANY/Brake-Bleeder-Tool/p/36529_00000

So with this, I just won't have to open/close the bleeder after ever squeeze, right? Once the air is purged from the clear tube and check valve, I should have a solid (air-free) line, so I can pump until I get no more bubbles.

The idea of "building pressure" is odd to me. Fluid is non-compressible, so it if there are no leaks, and solid fluid between MC piston and SC slide, then I should have instant pressure. I really think the slave cylinder is leaking, but i have not gotten it off yet to verify.

Correct, all you have to do is open the bleeder once you have the line in place, the check valve allows you to not have to close the bleeder after every pull of the lever. Once you can see no more air bubbles in the fluid coming out, then you can close the bleeder and you should be done.

[BRad704]

Wow. Sometimes it's the simplest things..

I bought a small socket set at Lowe's this morning (good excuse to ride the Ninja), and just pulled the SC off the VFR. it was totally crudded up around the seal and barely moving... I cleaned the gunk out, reinstalled and BAM! instant pressure to the clutch. I have NO idea exactly what the issue was, but just wiping around the SC slide and reinstalling made all the difference in the world.

During the process, I did manage to pull the control rod out a few inches and then slide it back in place. Not sure if something was slipping/out of alignment on the other side.

Thank you all for all the attention and ideas on this. I'm sure it will happen again someday and I'll end up reading back through this thread for help again.

VFRD ROCKS!

[YoshiHNS]

ok Yoshi... don't be harshing our groove here. LOL.. the man needs a clutch (well, at least for starting and stopping purposes)!

Me? I'm all about the groove

Glad it was a simple matter of cleaning the SC a bit.

[BRad704]

Groove! YEAH!

Even MORE groovy than that.