clutch master cylinder leak

[bobbar]

Leak on my clutch master cylinder just started on my 14 after 8000mi. Leak is very slight and shows up on left side as fluid shows up on top working up from top lid and casting. Local dealer has never seen this type of leak on a tenere. They took it apart, cleaned gasket and reinstalled lid. The leak showed up again an hour later. They are going to call yamaha about it on how to proceed on this. Bike still under warranty. Anyone have or heard of this problem. I looked around the forum but didn't find posts about this.

 

[Don in Lodi]

Leak on my clutch master cylinder just started on my 14 after 8000mi. Leak is very slight and shows up on left side as fluid shows up on top working up from top lid and casting. Local dealer has never seen this type of leak on a tenere. They took it apart, cleaned gasket and reinstalled lid. The leak showed up again an hour later. They are going to call yamaha about it on how to proceed on this. Bike still under warranty. Anyone have or heard of this problem. I looked around the forum but didn't find posts about this.

Can't quite picture where the leak is. Why won't they just replace it?

 

[Harry Dresden PI]

After 4000 miles I have not seen any leaks on my 2014 ES.

I did bleed / flush the whole brake and clutch systems when I swapped out the std hoses for + 2" ..... and .... noticed the all the fluid was yellow like it was starting to get moisture in it.

My 2014 bike did sit in the dealer for some time as I bought in in Jan of this year.

Bike seems to brake harder after I bled the system but no change in clutch action.

Please keep us posted on your results.

 

[Nimbus]

Mine did this a few times. Intermittent seeping (maybe a drop, but mostly just a seeping mist that left it a bit damp). It most recently did it during an extended crawl in backed up traffic that required lots of clutch work on a heavily loaded 2 up trip.

 

[Dogdaze]

If there is seepage from the actual cover, I would check to see if the rubber diaphragm is seated correctly on the white plastic inner guard, also when replacing the cover make sure the screws are snug, do not over tighten. There will never be a complete air tight seal, as the two parts that come together are aluminium and there is not a rubber gasket, also, DOT 4 fluid does have a tendency to 'creep' and often looks worse than it is, but make sure it is not left on any painted surfaces, or you will be pissed.

 

[Nissbird]

I recently changed the fluid in my clutch master cylinder and it leaked out the top because I had very slightly over-filled it. I suggest you take a bit out and see what happens.

 

[Lutsie]

Had this problem with my old bike as did my father in law. Found that drying off the diaphragm particularly the edges kept it from weeping.

Dogdaze is right it will strip the paint right off like paint thinner. .. father in law now has a brushed aluminum finish on his cap.

Sent from my SGH-T999 using Tapatalk

 

[mrpete64]

When you take the cover off make sure that it is put back on "exactly" as it came off. There are two VERY small slots in the rubber gasket on the top. The first time I did it I had a leak. When my friend came over to look at why it leaked..took off the cover...and looked very carefully and you can see these two very very small slots. If they do not fit exactly it will leak.

Mr. Pete--------->
aging hippie

 

[bobbar]

Thx for replys and info. I will keep ya all informed with what the mothership wants to do with it as it is still under warranty.

 

[bobbar]

Yamaha wants to replace the master cylinder. Part to be ordered today by my dealer. No explanation on what my have gone wrong or even if it may have been a transient occurance. Proactive, quick. I'm a bigger fan than ever of our yamaha family.

 

[steve68steve]

Sorry to kick up an old thread, but I just experienced this issue today following a clutch line replacement (Jaxon's +2").


Since I replaced clutch and brake line, I washed the bike off before taking it for a test ride to get off any dumped brake fluid. While riding, I got a little bit of spray which I assumed was water, but a few miles in I realized it was brake fluid. A few drops were clinging to the top of the lid, there was spray inside the left handguard, and wet runs in the area of the clutch pivot and on the banjo bolt.


When I got home, the master cyl was nearly empty. I added fluid, wiped everything off, re-installed the cover mindful of not over-tightening, then washed the whole area again and parked it.


I think I had it over-filled and the gasket displaced some fluid. I think it's possible I over-tightened the first time, too, and I didn't check the fit of the gasket and the white plastic filler panel. If it leaks now, I'm stumped. Will try and remember to update thread.

 

[steve68steve]

UPDATE: when I checked the master cylinder, the level was very low - most of the fluid had leaked out.


I filled and replaced the cap and noticed overflow caused by the rubber bladder taking up more space than I accounted for. It was displacing fluid. Cleaned everything up and adjusted fluid level so that I could install cover without any spillage/ overflow. Problem solved. The fill volume I wound up with higher than the level after the leaking event, tho:


So apparently if the lip/rubber bladder of the reservoir is wet it will continue to wick fluid out; if it's dry it's leak proof.

 

[ord13]

Same issue on 1700 VMX (same master-cylinder).
Just replacing the rubber part under the cover stops the leak until next time.
Had that too on my ST twice during first year, no more since...

 

[bobbar]

I never got the warranty service done in ny and have the bike here in Florida. Still sweating fluid so I took the advice and wicked a bit of fluid out of the reservoir and cleaned and reinstalled top. Noticed when I took it apart the two screws holding the top were almost loose. Could be they were never tightened well by the tech or loosened from vibes which I doubt. Anyhow, seems to be ok so far after 500 Mi.

 

[jc450]

I had this exact problem after bleeding clutch. The rubber diaphragm has to be correctly oriented and perfectly seated along the lip of the cover when reinstalling the cover. It was slightly off center when retightening the first time and had become slightly deformed in the middle and caused a slight leak after riding and using clutch. Re-seating and ensuring it's properly seated fixed the problem.

jc

 

[Defekticon]

Awesome info. I'm having this issue now, and just found this thread. Thanks all!!