Leaky clutch?

[fintip]

My clutch started going limp on me lately. It was slow, so for a while I wondered if I was imagining it, but eventually it got to the point where I had to pull the clutch all the way in to the grip to get it to disengage (while it was disengaging when I was pulling it even slightly when I first got the bike to Austin).

So I finally went and bought some DOT4, on the suspicion that it was leaking somewhere. Sure enough, the cylinder was quite low. Fluid also looks pretty dirty, should flush it soon, haven't flushed it since I got back.

So, filled it up, lever working well again. But I am noticing fluid leaking out of the master clutch cylinder. Now, I haven't seen a gasket quite like this before--it's shaped like the cylinder, and goes in?--so I'm wondering... The 'gasket' that really seems like a rubber mold of the interior of the master cylinder there, it seemed a bit misshappen, difficult to get to fit on all edges, wanted to sit in a 'squeezed' position a bit. Is it just old and needs to be replaced, or did I install it wrong this time? Is leaking there typical? It also seems like on the outside edge of the lid, there's a tiny little cutaway... Is that an overflow cut or something? Maybe I just overfilled it considering how much the gasket displaces, and the leaking I am seeing now is just not relevant to my original leak problem?

It's also worth noting that as I removed my bellypan fairing piece the next day, I noticed that the rear left tab had almost completely ripped from the rest of the belly pan, so that the fourth screw there was no longer supporting the weight of the whole pan. I am driving without it for now until I can get it ABS welded and repainted in the future. But I'm not sure where the slave cylinder is for the clutch--would a leak from it have pushed a wearing away at the plastic there?

Thanks,
Kyle

[fj11.5]

hi kyle,, would say the mc gasket needs replacing, if not a whole rebuild kit from rpm, or upgrade to a later one,, as for the bellypan,  thats common if the clutch slave is or has leaked,  fluid eats plastic, , ps, did that seat latch show up for you

[FJmonkey]

Kyle, too bad you did not notice it at my place, the rebuild is easy. The leaking part is likely the salve near the oil filter. It lets you know its leaking by quietly dripping brake fluid onto the ABS plastic lower fairing causing it to get brittle. It also causes the paint to bubble and peal off anything it touches. Then after a little while longer the clutch seems to be dragging and you can't pull the lever in enough to change gears. If it is leaking at the top, then that is more a contamination and pealing paint issue. You need to fix the salve to stop the real leak. Then work on the master if that is leaking as well. I have my old master off the bike and the gasket is in good shape if you need it.

[SlowOldGuy]

Your slave cylinder is shot.  Needs a complete rebuild or possibly replacement.

The "gasket" in the master cylinder also acts as a diaphragm and expands as the fluid level drops.  This allows the fluid level to drop without causing a vacuum to form in the reservior.  The small cutout is above the diaphragm and allows air to enter above the diaphragm so it can expand.  When you top off the fluid, reset the diaphragm by folding it up into itself, it should not displace any of the fluid.

DavidR.

[Tiger]

I'm not sure where the slave cylinder is for the clutch

Kyle,
Follow your clutch line away from the master cylinder and it will take you to the slave cylinder. ..

If you have dirty fluid in the system, I would take this as an opportunity to rebuild the master cylinder & the slave cylinders...not a big job as such.

I also fitted a new Stainless Steel braided clutch line (that matched the new S S brake lines!!).

Once done, bleed off and your good to go for another 20 odd years   

John.

[movenon]

When I got my FJ it needed seals in the clutch slave cylinder and I had RPM send me new seals which are great but in hind site I probably should have just replaced the slave unit with a new one. It is on my list list to do. Mine is not leaking but the clutch action is not the best. The original unit has probably been on there for over 20 years and the bore worn from the piston or corrosion in the bore from moisture. When you think about how many cycles the slave clutch get used in 20 plus years there has to be a fair amount of wear in the unit. I know its a bit more expensive but not outrageous and an easy to change out. It might surprise you how inexpensive a new unit is from Randy.  A word of caution: If you pull the slave cylinder off... do not start the engine. It has been done and it starts a another topic of conversation. 

[Mark Olson]

hmmmm, I seem to recall somebody telling you to rebuild your clutch slave way back in nov during your epic adventure, because it was gonna leak and eat your faring.

oh , wait a minute that was me.

[fintip]

I don't remember being told to rebuild the clutch slave, though I did know that the brake slave had been rebuilt by the PO. But certainly not something I could have afforded to do in Seattle; I had to overdraft $40 just to have the gas to make it home in the end, and do some work with my family to earn the money to make it back to Austin. 

David, that's great info about the diaphragm/gasket. That makes a lot of sense. Still kind of wondering how to fold it properly, but maybe it'll make sense when I pull it apart again. Clever design, though.

Tiger, yes, I know how to find it. I just hadn't gotten to it yet, and thought about the theoretical connection later. It was dark and cold out, so I figured I'd just post my conjecture rather than go outside with a flashlight and check.

Movenon, Thanks for the reminder about not starting the bike with the slave off, I've seen some of those threads, sounds painful. The new one seems to be this guy here, at $80? And the rebuild kit is this guy at $20?

Anyone else weigh in on rebuild vs. replacement? If a rebuild will be just as good as a replacement, I'd rather save the money and gain the experience. On the other hand, I don't like doing work if there's a question mark about possible future failure that will remain, and would rather do whatever will last. Would love some feedback on this.

Monkey/David/anyone else, if I just overfilled the master, and didn't fold the diaphragm properly, and sealed it up tight, is it possible that with squeezing on the clutch lever I'd see it overflow and appear to leak out the master through the air intake for the diaphragm? Trying to diagnose whether my master is also bad.

Everyone: Is there a definitive way to establish that the slave is indeed what is leaking? Is that invariably always where this tends to leak? I'm leaning towards replacing brake fluid with DOT5 in the future, is there any reason not to do the same with the clutch?

Rod So sorry I forgot to get back to you on that! I had seen your PM when I was busy, and then hadn't gotten notified of it again. Yes, I got the lever, haven't installed it yet. Was trying to think of something worth sending to you in return, finally came up with something, hope to send it your way soon. Hope you'll like it. Thanks so much, I brag to people about this forum by mentioning your act of generosity there.

[Dan Filetti]

Everyone: Is there a definitive way to establish that the slave is indeed what is leaking? Is that invariably always where this tends to leak?

VERY common failure point.  I'd bet a 10 spot that this is your problem.  A good way to tell it's leaked is to look for chipping/ peeling off paint down by the slave.  The leaking fluid is paint corrosive and it'll show.  However, it can be hard to tell if the corrosion happened before and the paint was not repaired then.

Most folks are successful with a simple re-build as apposed to a full slave replace. If the piston is badly corroded then you may need to replace the slave, but this is not all that common. 

Good Luck,

Dan

[movenon]

Mine had some minor corrosion in it. I cleaned it up as best I could and rebuilt. It works just not as well as it should. Which leads me in the DOT 5 issue. I vote no on DOT 5... Unless they have improved it a lot my understanding is DOT 5 will not absorb moisture. So water can accumulate in the lower reaches of a cylinder and contribute to corrosion. I would use DOT 4 or 3. I would much rather it absorb moisture and flush every other year or so. Most discount auto store carry DOT 4 you just have to look for it. The good news for you is that the clutch cylinder is easy to replace or rebuild.
                                                                                                                                 George

[Mark Olson]

just rebuild it , easy to do .  get the kit from Randy at RPM it comes with all the bits and you get a seal for the pushrod as well.

you never know when they are gonna fail , some guys carry a spare kit when they ride a long trek.

mine took a shit on the norcal renegade rally one year and I had to top off fluid at every rest stop, and fan the clutch lever at every stop sign till we got back.

made for some interesting riding.

[SlowOldGuy]

Kyle,
Get the diaphragm folded correctly and reinstalled then fill the master to about 3/4 of the sight glass (with the bars turned so the master is level).  Carefully position the diaphragm and the master cover and lightly tighten the 2 screws.  If you overtorque it, the cover will squish the gasket out. 

Usually a failing master will leak out of the piston shaft.

There is absolutely nothing wrong with using DOT 5, but you need to disassemble everything to completely clean out the old fluid if you convert.  I've been using it for 25+ years in 2 FJs with NO, NONE, ZERO problems with corrosion in the brakes or clutch systems.  I had DOT 5 in the front brakes of my '85 for over 14 years (never changed or bled it).  I replenished it when I converted the front end and installed monobloc calipers.  Disassembly of the stock calipers showed NO corrosion or any indication of "trapped" moisture.

My recommendation would be: Do not spit, piss or spill your beer into the master cylinder reservoir when filling with DOT 5 and you shouldn't have any "moisture" problems.

DavidR.

[fintip]

Well. Damn.

So Last Time, things leaked slowly, I assume out of the slave clutch cylinder, and so I pulled the lid off the master cylinder to replenish the fluid so in the meantime it'd still be functional. Two things about that first time:

1. When I tried to just do it quickly at an Advanced Auto Parts, they only had a standard (non-metric) allen key set. Because my master brake cylinder had phillips screws on it, while my master clutch cylinder had allen screws, I figured there was a small chance that they might be standard allen screws and not metric. So I tried it, and it slipped pretty easily, damaging the screw's allen side a bit. I promptly went and purchased a metric allen set. I was able to get the screws off with the allen set, and replenish the fluid level, but

2. I was unsure of how to use the diaphragm gasket (about which I later asked about here, and got good responses on). So evidently I installed it wrong, because it continued to leak out of the master cylinder at an even faster rate than it had been leaking out of the slave cylinder...

So I went to refill it again yesterday, and install the gasket/diaphragm properly... And I couldn't get the screws out. I was trying to be gentle, and used some liquid wrench, but trying just made it worse, until I had to admit that the screw was just stripped. I guess when the fluid kept leaking last time, I assumed I had to torque the screws down somewhat tight to get a good seal. Or perhaps warmer weather caused a marginal bit of expansion, causing it to tighten some. In any case, one of the allen screws for the master cylinder stripped.

So, I went and got a #1 screw extractor and T handle. Drilled my pilot hole into the screw, started turning the extractor slowly and carefully... And snapped it.

Yup. Broke an extractor in the screw. Talk about a series of unfortunate events.

So, unless someone had a brilliant idea I'm missing (I guess I could still try a dremel, and just deal with carved indents in the lid around the screw?), I'm thinking I might just need to get a new master clutch cylinder?

Other possible idea... If I pried up the lid and broke it off, I might be able to get a vicegrip on the screw and pull it out, and then get a replacement lid off of an otherwise derelict or decommissioned master clutch cylinder.

What do you guys say?

Trying not to be too annoyed... In the meantime, borrowing a friend's '83 R100RS. Some people are romanced by this old bike. I'm not one of them. Terrible shaft jacking, uncomfortable seat, grips, etc.; completely crap suspension; heavy... At least I'm still riding, eh?

Thanks in advance,

Kyle

[FJmonkey]

Kyle, maybe a member has an old master you can get. I remove my screen and use a hammer driven impact driver to knock the Phillips bit loose. I am thinking of changing the screws to a hex to ditch the Phillips. I have a spare OEM brake master, but no clutch master yet. Good luck.

[rktmanfj]

Kyle, I just got back home from a trip, so give me until tomorrow to check.

I'm pretty sure that I still have the old m/c from my '89.