clutch master cylinder reservoir leaking

[jtk1531]

anyone have/had brake fluid leaks on the clutch master cylinder reservoir?
my bike (2012) seems to need new reservoir diaphrams replacements everytime i open it up to change the fluids. if i reuse the diaphram, it'll usually leak. new diaphram, no problem till the next time i need to open it up.
the last time that i opened it up was in december 2015. today i replaced the clutch slave cylinder, closed everything up, and again it's leaking. this time, it seems to be leaking from the screws that holds the reservoir cover (black) down. it'll leak when i park the bike on the side stand with the handle bar turned to the left.

i don't think i'm over-tightening the cover screws, i usually tighten the screw down till there is a very tiny gap between the black cover and the reservoir.
is there any trick or method to being able to reuse the rubber diaphram at least a few times?

[connie_rider]

I've never had a leak.
Possibly you overfilled the reservoir?
DO NOT let any brake fluid get on your paint!!!!

Ride safe, Ted

[PH14]

When you are reinstalling the cover, is there any fluid in the holes for the screws, or fluid along the sealing edges?

[B.D.F.]

This is one of those situations that is really hard to diagnose over the 'Net....

I have had many reservoirs (clutch and brake master) open on a bunch of C-14's of all years, always re- used the diaphragm, and never, ever had a leak. You mention leaving a gap between the cover and reservoir body; this may be the problem. Tighten the screws down all the way and draw the cover down onto the top of the reservoir. I agree with you about not over- tightening the screws but they do have to be holding the cover firmly against the diagram lip or it will leak. I usually tighten the screws buy holding just the shaft of the screwdriver (Easy Boys!) and not using the handle at all- this provides all the torque needed but does set the screws all the way down.

Otherwise, I cannot imagine what could be causing your leak. ?? If everything is clean, the system should seal very well.

Brian

anyone have/had brake fluid leaks on the clutch master cylinder reservoir?
my bike (2012) seems to need new reservoir diaphrams replacements everytime i open it up to change the fluids. if i reuse the diaphram, it'll usually leak. new diaphram, no problem till the next time i need to open it up.
the last time that i opened it up was in december 2015. today i replaced the clutch slave cylinder, closed everything up, and again it's leaking. this time, it seems to be leaking from the screws that holds the reservoir cover (black) down. it'll leak when i park the bike on the side stand with the handle bar turned to the left.

i don't think i'm over-tightening the cover screws, i usually tighten the screw down till there is a very tiny gap between the black cover and the reservoir.
is there any trick or method to being able to reuse the rubber diaphram at least a few times?

[jtk1531]

thanks for the replies...

- fluid level is at the min level. fluid still reaches the top of the reservoir when the bike's parked on the side-stand.
- i did wipe off all fluids between the diaphram and the plastic inner piece that sits between the diaphram and the metal cover.
- i used to tighten the screws all the way down, but i thought it was causing the diaphram to be squeezed out of shape (heat under the sun, etc). so when i replaced it with a new one, i tried leaving a small gap that's probably less than a millimeter.

i'll try tightening the cover down just a bit more.

by the way, reverse bleeding the clutch lines with a 50ML syringe was awesome, definitely recommended if you have the clutch line dry. with a big syringe, i can push fluid in through the bleed port at the clutch slave cylinder with enough force to have a tiny (5-10mm) fountain at the clutch master.

[gPink]

thanks for the replies...

- fluid level is at the min level. fluid still reaches the top of the reservoir when the bike's parked on the side-stand.
- i did wipe off all fluids between the diaphram and the plastic inner piece that sits between the diaphram and the metal cover.
- i used to tighten the screws all the way down, but i thought it was causing the diaphram to be squeezed out of shape (heat under the sun, etc). so when i replaced it with a new one, i tried leaving a small gap that's probably less than a millimeter.

i'll try tightening the cover down just a bit more.

by the way, reverse bleeding the clutch lines with a 50ML syringe was awesome, definitely recommended if you have the clutch line dry. with a big syringe, i can push fluid in through the bleed port at the clutch slave cylinder with enough force to have a tiny (5-10mm) fountain at the clutch master.

Is this correct?

[B.D.F.]

Well if you are leaving a gap of any size at all, that is the source of your leak. You must tighten the aluminum cap down onto the plastic insert that bears directly on the diaphragm lip, against the reservoir body; that is what makes the system seal in the first place.

Brian

<snip>


- i used to tighten the screws all the way down, but i thought it was causing the diaphram to be squeezed out of shape (heat under the sun, etc). so when i replaced it with a new one, i tried leaving a small gap that's probably less than a millimeter.

i'll try tightening the cover down just a bit more.

<snip>

[gPink]

Do you have everything shown in the correct order? Cap...plate...diaphragm...plate?

[jtk1531]

Do you have everything shown in the correct order? Cap...plate...diaphragm...plate?

yeah, same order as per the manual.
cap, plate, diaphram (attached under the plate), and the plastic/foam piece that floats on the fluid.

[zarticus]

Tighten it up !

[VirginiaJim]

I would also make sure that the metal cover isn't warped or bent.  Mine has never leaked.

[elp_jc]

You definitely left the screws loose man. You have to get them tight. Not overly tight, but tight. Since you don't seem to know how much by feel, get the torque value and use a 1/4" in-lb torque wrench to do the job right. And yes, remove it, fill the reservoirs to the max line, and clean everything again, including the holes where the screws go before reinstalling the cap. Good luck.