Clutch MC Fluid Contamination

[yohavos]

Hey everyone,

I've got a few issues with my 1994 HZJ75 that I'm in the process of sorting out, and could use some pointers. Rig is RHD, has a NA 1HZ and an H55 trans.

I've done some searching but am not finding any answers specific to one of my issues. I think I've got a rear main leak, but that may or may not be related to this.

I was driving this morning and after getting on a main road about 5 minutes after taking off, my clutch kind of disappeared on me. I was able to "tractor shift" my way to a grocery store where I stopped to diagnose my issue.

My clutch MC was very low and had what looked like oil-contaminated fluid in it. I'm not sure how it's even possible, but I swear this is oil. I bought some DOT 3 and a turkey baster at the store and did what I could. After some parking lot antics, the clutch felt great and it got me home just fine.

The PO (stand up guy, very helpful, talked me through some things this morning) recently replaced the slave cylinder and is 100% positive he used DOT 3 in the system. He wondered if some water could have gotten into the system somehow, but after doing a bench test with some DOT 3 and some water this morning (I'm not a great mechanic, and had no idea what it would look like, so I tried it in a glass jar) I'm convinced it's not water.

After doing some searching I found that a failing slave cylinder could leave the fluid dark with bits of gasket and gunk, but (and I'm hoping the pictures show this) this really reminded me of milky 90W from a differential with some water in it.

My rear main leak (diagnosed, but theorized based on searching) assessment comes from the fact that I have oil leaking from around where my slave cylinder is on my clutch housing/transmission. I haven't started a thread on that as I'm pretty confident it's the rear main, but I include this information to see if that might have something to do with the fluid in my clutch MC.

Also, just to throw it out there, if the slave cylinder was loose or not installed correctly, would oil leak out from around it?


I appreciate any info or advice. I don't usually post tech questions as I can generally find what I'm looking for, but I know you 70 Series guys are a great group and have some outstanding minds in here!


Mike

 

[Tapage]

I don't think it's is possible you have any other engine oil in your clutch system .. but .. if you have a failing slave and any deep water cross ( enough deep to reach the slave level ) there you have your culprit .. with failing seals that could be a chance ..

 

[BigDaveGrrr]

You are not mistaking the black rubber float for oil are you?

 

[kbushnz]

Looking at the pic, the oil looks like it is full of fine aluminium. I would say the slave or the master piston has been rubbing on the bore. The only way to confirm it is to pull it all apart and take a look...

 

[yohavos]

Thanks fellas. After talking to a mechanic today and getting a run through of the hydraulic assisted clutch setup, I'm looking back on my question and thinking it's a bit dumb! The system is closed, and there's no way oil could get into it without being added.

I agree with you Calvin, I'm thinking the fluid wasn't in great shape and it's definitely getting something in it. The slave cylinder was recently replaced but when I checked the fluid it was very low, so I'm assuming there is a failure somewhere that allowed for the fluid to escape.

The lines all look straight, without any indication of leaking. The firewall behind the clutch MC is worn where it obviously leaked long ago, but there's nothing fresh. I checked my footwell around the pedal, and it's bone dry. I've cleaned the slave cylinder (which was recently replaced) and am keeping an eye on it for any weepage. A mechanic had me work the clutch while he observed the slave cylinder and couldn't see any leakage, but I'm going to monitor fluid levels and see what I can see for a while.

I plan on flushing and bleeding the system tomorrow to see if I can get the fluid clear again. If it gunks up, I'll know something is up.

Thanks for the insight, and sorry for the newb questions!

EDIT: Dave, that's the fluid, not the plastic float. I wish it was that easy!


Mike

 

[spotcruiser]

So, Mike, did you get your clutch hydraulics cleaned out and functioning properly?

 

[yohavos]

So, Mike, did you get your clutch hydraulics cleaned out and functioning properly?

Not yet, the truck is with Tor getting the head work done. Hopefully I'll be able to track down the clutch issue once I get it back.

Something is leaking, I just need to figure out what.