Strange- Clutch lever goes to bar with no resistance

[josephjhaney]

This is a strange one, and I think I have the answer, but wanted to ask here-

Got my vmax last year, 85 with 1,950 miles on her. Slave cyl for the clutch was leaking, well, that's to be expected, had the shop rebuild the slave. This year, the master cyl was leaking, same deal, shop rebuilt master. Has been great for the last month, no issues. This week we went to dinner on the bike, and I noticed the engagement position of the clutch seemed sooner than it had been, made a mental note to keep an eye on it. Next morning went to take her to work, clutch isn't releasing at all, lever drops right to the bar when pulled, no resistance. I will bleed it with my mightyvac, and I'm sure that will take care of it for a while, but I suspect it's the freaking rubber line that's been on the bike since 85. My question is, why wouldn't I see ANY signs of fluid on that line, or dripping from it, with that much air going into the system that quickly?

BTW I ordered braided steel lines that should be here in a week or so, so that will take care of the issue I think, and if it doesn't I'll be posting back here more confused than ever.

Joe

 

[Traumahawk]

Well the rubber line could be rotten on the inside......and so expanding so pressure isnt building. Of course that is assuming no air in the line.....etc.

 

[Fire-medic]

It's a good idea to replace the lines where brake fluid is involved. Try the syringe 'reverse-bleed' method, I think you will find it faster & easier to achieve a firm lever for your clutch. Do a search if you aren't familiar w/the method.

Just a suggestion, you may find it's less expensive to buy a new brake or clutch master cyl when you factor-in the labor cost. When a replacement NOS master cyl is ~$100 and a kit is ~$30, I'll go for the new component. Bolt it in, bleed, & go. No messing w/rebuilds. This is my philosophy since the last 3 rebuilds I did only 1 was successful. I inspected the bore pre-rebuild, but even repeating the rebuild (same kit) to see if I could find something, didn't do the trick. Plus, you have the security of a NOS part instead of a 29 y.o. part.

I've had deteriorated hydraulic lines on cars, trucks, and bikes, it happens.

 

[josephjhaney]

It's a good idea to replace the lines where brake fluid is involved. Try the syringe 'reverse-bleed' method, I think you will find it faster & easier to achieve a firm lever for your clutch. Do a search if you aren't familiar w/the method.

Just a suggestion, you may find it's less expensive to buy a new brake or clutch master cyl when you factor-in the labor cost. When a replacement NOS master cyl is ~$100 and a kit is ~$30, I'll go for the new component. Bolt it in, bleed, & go. No messing w/rebuilds. This is my philosophy since the last 3 rebuilds I did only 1 was successful. I inspected the bore pre-rebuild, but even repeating the rebuild (same kit) to see if I could find something, didn't do the trick. Plus, you have the security of a NOS part instead of a 29 y.o. part.

I've had deteriorated hydraulic lines on cars, trucks, and bikes, it happens.

Good advice, I might take it if this line doesn't do the trick. I don't see ANY fluid coming from the newly rebuilt master though, so while that could be the issue, I'm hoping it's the line and the replacement will resolve that.

I tried the reverse bleed before, but couldn't seem to get the fluid to push, I didn't want to open the bleed valve too far, that fluid wreaks havoc on paint, and I have already had some issues with dripping it on parts. Also, does the clutch lever need to be against the bar for that? or should it be out?

Joe

 

[jfeagins]

Most likely, if you don't have fluid leaking, and you are getting a limp clutch, you still have air trapped inside the lines. When the big air bubble makes it's way to the top, it will sit in the line at the banjo bolt where the line attaches to the master reservoir. Try bleeding there by loosening the banjo, to burp the bubble out. Then top off the reservoir, being careful to have enough fluid in it so as to not allow more air in while deep cornering etc..., but not too deep as to cause fluid to weep out around the lid gasket.

 

[Fire-medic]

You can leave the clutch or front brake handle out, you don't need to squeeze it while reverse-bleeding. Open the bleed port fully, some people use teflon tape to minimize the leakage. I have done that for either the mityvac 'pull the brake fluid down' or the 'syringe pushes the brake fluid up' methods.

Good advice, I might take it if this line doesn't do the trick. I don't see ANY fluid coming from the newly rebuilt master though, so while that could be the issue, I'm hoping it's the line and the replacement will resolve that.

I tried the reverse bleed before, but couldn't seem to get the fluid to push, I didn't want to open the bleed valve too far, that fluid wreaks havoc on paint, and I have already had some issues with dripping it on parts. Also, does the clutch lever need to be against the bar for that? or should it be out?

Joe

 

[josephjhaney]

I think I might have a one way bleeder port. I tried to reverse bleed the lines, but the pressure built up and blew my plastic line off the nipple. I decided to just fill the reservoir and do it the old way. After about an hour of pump the lever 10 times and let the pressure/air out, I've got pretty solid feel to the clutch now, though the engage point seems a little quick off the bar still, so I may need to bleed it more.

Joe

 

[Fire-medic]

Yes you have air in the system. Continue to bleed it.

For reverse bleeding, be sure you have the bleeder open, once you do, with your syringe hooked to the bleeder, squeeze the lever and you should be displacing fluid in the clear plastic line to your syringe. It's easy enough to see if you have a check valve or not but if the above doesn't convince you, you will need to remove the bleeder to check it.

 

[josephjhaney]

Yes you have air in the system. Continue to bleed it.

For reverse bleeding, be sure you have the bleeder open, once you do, with your syringe hooked to the bleeder, squeeze the lever and you should be displacing fluid in the clear plastic line to your syringe. It's easy enough to see if you have a check valve or not but if the above doesn't convince you, you will need to remove the bleeder to check it.

My wife will be thrilled to hear we need to bleed the clutch more. She was very happy to help me last time. Haha. Actually, she's freaking awesome, didn't gripe once, and LOVES riding the bike. Not many like her.

I'll update after I pump, bleed, repeat this weekend.

Joe

 

[josephjhaney]

So, quick update, that seems to have done the trick. So far the clutch has been working great, so I think she's all set. Thanks everyone!

Joe

 

[DMAN999]

So, quick update, that seems to have done the trick. So far the clutch has been working great, so I think she's all set. Thanks everyone!

Joe

Glad to hear you got it worked out.

 

[Bill Seward]

My 85 did the same thing a year or so ago.. I took the cover off the reservoir, and pumped the lever. A huge air bubble came out into the reservoir from the line! I pumped the lever about 6 or 7 times till the bubbles stopped, filled the reservoir, put the lid back on and have had no problems since...
The reservoir was properly filled when the problem occurred, so I don't think it was an air bubble getting in from the reservoir..