Does clutch fluid leak into engine oil

[TOOC]

Hi All,
Ie have recently rebuilt the clutch disks and after a two months in storage before testing the new clutch I noticed the reservoir had emptied. I also noticed that if the clutch is held pulled with the engine running and in gear the clutch begins to engage and the bike creeps. I figure the fluid is leaking across the slave (or master) seals under the pressure.  I refilled and bled but after 20mls it almost emptied again.I  have ordered new slave seals but am asking if the fluid leaking by the slave seals finds its way into the engine oil or is there a drain pipe attached to the slave. I did notice light fluid leaking from one of the drain lines when the bike was stopped. If the brake fluid has leaked into the engine oil (two reservoir fulls) is it damaging to the engine and seals; I guess I better change the engine oil before any driving.
Thanks
Oliver

[SpidyJ]

My guess is needs a master.....

[F6BANGER]

The reservoir holds about (guessing) 2 oz. If you dont see that on the floor, Im guessing it is getting into the motor thru the back of the clutch. Its gotta be going somewhere?????

I have heard brake fluid will cause the rubber seals in your engine to swell and weaken, then tear, leak weep and cause you to be doing a reseal job. Brake fluid is hydraulic fluid and the seals in your brake system have a different composition than the seals in your engine.

I would drain the oil, add cheap dino oil run it for a few minutes and drain it out and add fresh oil. Dont forget about the filter......

[Hoser]

Does'nt the clutch discs use the engine oil for lubrication?  You know, wet clutch?  Or are you thinking of the clutch fluid in the clutch lever. I'm all confused now.     Hoser ???

[Denny47]

Hoser, the clutch slave cyl. is on the back of the engine near the driveshaft output. Might possibly leak into the engine oil. Think it was discussed hear not to long ago but I have not searched.

[vanagon40]

It seems unlikely to me that the slave cylinder would leak into the engine, but I really have no idea.  The only clutch slave cylinder I ever replaced was on an old Subaru XT.

You might want to check with Squealy as I believe he recently replaced a leaking slave cylinder.  See this thread.

Or check with Jabba.  I think Jabba is Squealy's mechanic or Squealy is Jabba's mechanic.  I can't tell them apart (they both claim the other is better looking).

[Michvalk]

The fluid from the clutch slave CAN leak into the engine oil, and will if the slave is leaking. There is a kit to rebuild the slave, and I would do the master at the same time. Might cast an eye on the line from the master and to the slave for any leaking as well, while you are at it. OH, and change your oil and filter

[Hoser]

Thanks Michvalk,  for splaining that.  I no longer am confused.   Hoser 

[Ricky-D]

Although the clutch fluid can leak into the crankcase, it's not supposed to and there is a seal that's supposed to prevent that exact thing.

On the clutch slave housing there is a drain hole that is supposed to allow any leaking clutch fluid a path to exit.

Since the whole assembly is going to come off, it's a simple thing to insure a good seal on the rod and a clear exit in the drain hole.

***

[TOOC]

The diagram posted by Denny47 shows clearly a fluid bleed hole in the clutch casing holding the slave cylinder and this along with the seals ring 14 would indicate that Honda designers made provision to avoid clutch fluid leaking into the engine oil. The Service and Repair manual diagram does not show this bleed hole so the detail in the diagram posed by Ricky is very helpful.  I had just replaced the clutch disks (rivets sheared on the damper plate) and in the process of removing and refitting the slave cylinder it must have been damaged because before the clutch repair, the clutch reservoir was not lowering in fluid. Before I fit the new slave piston seals I plan to test if the all of the fluid is actually leaking through the leak hole in the casing by holding the clutch lever pulled and watching for old seeping from the leak hole. I will remove the slave and then try to see if there is any evidence of oil getting past the oil seal into the clutch casing.
Thanks again for all your help and I will report back the final outcome.
Oliver

[F6BANGER]

Any news yet?