Clutch Fluid Leakback

[NC2Stay]

My Vette is sick again - clutch. Because of a leak, the master cylinder was replaced last Sept. Been fine since. Former owner (last August) says the slave was "rebuilt" recently.

But, this weekend it started acting funny. Took it to my local guy (who is very good) and its not leaking, but if you hold the clutch in, it starts to engage lower and lower. It looks like the cylinder is not holding fluid, but letting it leak back around the seal. Reservoir is full.

Garage is going to replace both the master (on warranty) and the slave. Seems a bit of overkill.

Anybody have any ideas or experience on this repair?

Thanks, Bob

 

[Chris Kennedy]

It seems unnecessary to replace a Master Cylinder replaced so recently, but as to the slave cylinder it seems to me the right thing to do is to replace it with a new unit----generally, my experience with similar systems in other cars is that these clutch hydralics "rebuilds" don't work at all or don't last very long. At some point in the not too distant future I plan to replace the clutch hydralics in my '89 6-speed as a precaution, as they can fail quickly. Also replace the line between the master and slave cylinders.

Chris Kennedy
Houston, Texas

 

[ßill]

Hi Bob

My take is some what different than Chris. I look at the clutch hydraulic system is not a closed system. When you step on the clutch pedal the piston in the master cylinder pushes hydraulic fluid which pushes on the piston in the slave cylinder which moves the clutch. In order for the clutch to engage while the pedal is depressed fluid must leak from between the pistons. The only leak that would not be seen by a loss of fluid level in the reservoir would be a leak around the piston in the master cylinder. I do agree that both master and slave cylinders should be replaced as a pair, I think the problem is the master cylinder.

 

[froggy47]

I would do master & slave every 50k, I took a pass on the tube though.


I would do the m/c again in your case, just on principle.

 

[NC2Stay]

... I took a pass on the tube though...

My mechanic took a pass also. We did discuss it, but I believe he thinks the factory unit is better than a replacement, and if its not leaking, leave it alone. There is definitely no external leakage - the reservoir is full, just as it was when he did the master, and never filled after that.

The master is under warranty, so it won't cost me anyhow. Knowing this guy, he probably won't charge me for the slave either. I give him a lot of work on my 3 cars, and he stands behind what he does. Its amazing we have a guy of his quality here in the sticks.

He knows LT1's pretty well too. He is not a Vette fan, but has an LT1 in a big ol Buick Roadmaster - with Flowmasters!

Anyhow, hopefully the parts will be in soon and we'll see.

Thanks all for the comments.

Bob

 

[WhalePirot]

the slave was "rebuilt" recently.

That can mean something different to each owner. If either cylinder is pitted, at all, any new seals from a rebuild, will not last too long. The aluminum cylinders cannot be honed as I was used to with past machinery.

I have sought, but never found, a place that would sleeve the unit with stainless.

I still run my stock hose, despite a few M/S changes. I also change the fluid when it darkens substantially. I recall your being at the beach, which would point to quicker adsorption of water in your brake fluids. Water > corrosion of brake components and also, in our case, clutch actuating components..