1994 Coupe

I recently started to feel my clutch ceasing up or what I thought was going bad. After reading my posts in here, I checked my clutch fluid and noticed it was low. A real weird part to this is that the fluid resivoir has a rubber stopper/cup gasket on the top of it (black rubber). After getting a flash light and noticing that this was some kind of gasket or stopper I noticed that it was filled with brake fluid and possibley some rain water mixed in (seemed diluted) that may have gotten in through the tiny pin hole in the lid to the resivoir. I pulled out the rubber whatever and noticed that it was empty underneath. So I filled it to the full line. (Before filling I couldn't even get into gear and this happened within days, from working pretty good to screwed.) Anyways filled the fluid and then replaced the rubber cup. This thing is probably 2.5 inches deep or long. When doing this, the fluid started to be forced out of the top (the rubber deal being to long of big that it forces fluid out of the resivouir as i replace it back in and replace the lid. The stopper is deeper than the full and low line. I wrap a paper towel around the outside so that it doesn't come into contact with anything other than the resivoir.
So Im thinking this thing is the wrong one or that there doesn't even need to be a rubber what ever this is under the cap. It is a totally separate piece from the cap.

Does anyone have this in there car, do I need this or can I just take it out and use the cap only? There is a very small pin hole in the lid, so some rain could maybe make it in the resivoir and into the clutch fluid.

Thanks
Bob W

 

All our cars have that rubber cap dealie in there, not sure why.
Not near mine right now to check, but someone will chime in here to verify how deep down it goes.
Pinhole in the cap? Hmmmm....That doesn't sound right.

You will probably want to get some of the actual GM hydraulic fluid and flush the old stuff out. The GM stuff has some lubricating additives the brake fluid doesn't.

Just curious, have you disconnected your CAGS solenoid yet?

 

This is a stupid design that limits the amount of fluid in the master. This causes two problems--1 you get a small amount of reservoir capacity and run out of fluid and 2, it also concentrates any contamination build up resulting in more wear of the master cyl. and slave cylinder seals. ZF Doc has some caps with a pleated/bellows cover gasket that allows full usage of the reservoir. The stock filler gasket/ cup can be folded upon itself if you work at it, to gain some of the lost capacity. My slave cylinder recently failed due to contamination scoring of the bottom edge of the the lip seal. I spent hours trying to find a replacement $.50 lip seal with no luck along with trying to find a slave cylinder. Even the dealers are in short supply on slaves. Finally found a new slave cylinder via special order at PEP Boys at 60% of the price of the GM dealer one. In the mean time, I replaced the slave seal with an o-ring that got the slave cylinder working until I get the new slave. Visit www.ZFdoc.com for a cross sectional view of the slave and issues he has found with the slave seal installed backwards as well as quality issues with GM units.

 

This is a stupid design that limits the amount of fluid in the master. This causes two problems--1 you get a small amount of reservoir capacity and run out of fluid and 2, it also concentrates any contamination/wear particle build up resulting in more wear of the master cyl. and slave cylinder seals. ZF Doc has some caps with a pleated/bellows cover gasket that allows full usage of the reservoir. The stock filler gasket/ cup can be folded upon itself if you work at it, to gain some of the lost capacity. My slave cylinder recently failed due to contamination scoring of the bottom edge of the the lip seal. I spent hours trying to find a replacement $.50 lip seal with no luck along with trying to find a slave cylinder. Even the dealers are in short supply on slaves. Finally found a new slave cylinder via special order at PEP Boys at 60% of the price of the GM dealer one. In the mean time, I replaced the slave seal with an o-ring that got the slave cylinder working until I get the new slave. Visit www.ZFdoc.com for a cross sectional view of the slave and issues he has found with the slave seal installed backwards as well as quality issues with GM units.

 

This is a design that is present in all master cylinders. The rubber diaphragm is a moisture barrier that allows hydraulic fluid and air to go in and out of the reservoir (that's what that pinhole is for) without allowing the fluid to come in contact with and absorb water vapor from the air.

The rubber barrier is about one inch long and when you top off the reservoir, you cannot fill it!! You have to leave room for the barrier to be inserted. If you don't, then you'll have a big mess...as you've found out.
Richard Newton, in his book 101 Projects For Your Corvette, recommends this: "...fill the reservoir to 1/16" below the "low" mark so that when the "clean and dry" moisture barrier is re-inserted and the lid screwed on, the fluid level remains between the low and high mark."
I've found that this works nicely.

Hope this helps clear things up.

PS One more thing, if you "run out of fluid" then you have a leak in the system and should fix the problem.
Larry
code5coupe

 

Thanks for the Replies!