Clutch Master Cylinder Cap

[MG_Midget_74]

I was just noticing that when my wife pumped the clutch, fluid was coming out around the vent cap. You know how the cap is two pieces one piece which seals the cylinder and one piece that seals the vent hole. Anyone have this problem. My clutch is fine, have no air in the system. It works just like it did brand new, except for this leakage.

 

[JPSmit]

overfull? shouldn't be any back pressure there

 

[MG_Midget_74]

The thought had occurred. The manual claims to the bottom of the filler neck. When the fluid is there however it still comes out. Where do others fill theirs too?

Mine right now is approximately .25" below the neck and I am still getting a little.

 

[Midget78]

Are you getting a lot of fluid leakage or just a little? I keep mine filled to the neck and have no trouble. Im curious about the cap internal seal failing. I have a pretty good understanding of Hydraulics systems and although the cap may look like simple plastic my personal opinion is the dual seal is designed as such:
1.) The internal seal is designed to maintain positive pressure to the system and basically not allow leaking.
2.) The secondary seal is designed to allow a small vacuum source as it is necessary for the system to function through the clutch pedal operation.
I honestly think a new cap would fix the problem yet I dont know if you can get it without buying the entire clutch cylinder?
Im curious as to what fluid you put in there also?

 

[Billm]

When you are bleeding the brakes there is often (usually) a problem that if you leave the reservoir cap off then fluid will squirt up out of the cylinder pool (try it and you will be very surprised!). Your issue is probably just that the cap is stopping the fluid and then running around the cap and out of the threads. This isn't a problem but it just makes a mess. If you keep the cap reasonably tight when you are bleeding then you will minimize the issue.
Bill

 

[MG_Midget_74]

OKay for the two previous responses. The cap is brand new. It came from VB for what ever that is worth. The cap before the VB one, did the same thing. I am positive it is coming from the area above the cap but below the piece of plastic that will rotate. My clutch is fine and I am reasonably sure there is no air in there. My current solution was to get some gasket material. I cut a single piece of solid material the same size as the clutch MC opening, then I drilled a small 1/16 size hole in the upper part of the material. Problem appears to be solved.


Any thoughts on this solution?

 

[Midget78]

The fact that its a new cap really has me scratching my head. I checked mine and my fluid level is below the neck about an 1/8" of an inch (my clutch cylinder is also mounted on a slight angle). when I press in on the clutch pedal to the floor the fluid level raises just a bit but not a lot to cause it to over spill. Im wondering what the difference is that your fluid volume is so much more active.

 

[MG_Midget_74]

Well, I have not driven the car but have pushed the clutch in and out. I have seen no collection of fluid since adding the solid washer with the 1/16th hole.

Problem solved...?