TR2/3/3A Randall, let's try this

[Lukens]

This post is a continuation of my previous post concerning my clutch problems. Sorry for my blunder.:confusion:
Randall, help me out here. From the diagram, I just can't understand the workings of the valve seal. I understand that this diagram is for an integrated MC body, but it's virtually the same as mine with a separate reservoir. Here's what I "assume":
1) when the pedal is pushed, the seal is closed, forcing fluid to the slave.
2) when the pedal is fully depressed the valve opens. What is happening then?
3) as the pedal is released, fluid is allowed to "return" to the mc under pressure from the slave. It appears to me that if the slave were slow to return there will be a vacuum in the master. Would this not be a condition for air to enter the system?
Obviously I'm not seeing something. Educate me please.

 

[Lukens]

Not to exclude input from any other forum gurus. All responses welcome.

 

[TR3driver]

As shown in the inset at the top, the valve at 1 opens only when the MC piston is all the way to the right in the diagram, when the pedal is released. It has to stay closed when the pedal is fully depressed. The rod through the center (which isn't numbered) is what lifts the valve off it's seat, when the metal clip 6 pulls on the tab at the end of the rod.

I guess you're right, if the slave were hanging up for some reason (or perhaps the return spring is missing), the return spring inside the MC could pull a bit of a vacuum. But for most of the slave stroke, the springs inside the pressure plate are forcing the slave piston back into the bore with a lot of force. The only area where the hangup could occur (I think) would be the small freeplay distance where only the return spring is forcing the piston back into the bore. And it's still quite a bit stronger than the one inside the MC.

 

[Marvin Gruber]

Maybe trash or grit inside the slave holds the seal up to allow air in while being pushed back by spring but when pumped the seal has enough pressure to seal fluid going out??

marv

 

[Lukens]

As shown in the inset at the top, the valve at 1 opens only when the MC piston is all the way to the right in the diagram, when the pedal is released. It has to stay closed when the pedal is fully depressed. The rod through the center (which isn't numbered) is what lifts the valve off it's seat, when the metal clip 6 pulls on the tab at the end of the rod.

I guess you're right, if the slave were hanging up for some reason (or perhaps the return spring is missing), the return spring inside the MC could pull a bit of a vacuum. But for most of the slave stroke, the springs inside the pressure plate are forcing the slave piston back into the bore with a lot of force. The only area where the hangup could occur (I think) would be the small freeplay distance where only the return spring is forcing the piston back into the bore. And it's still quite a bit stronger than the one inside the MC.

BINGO!
I've been looking at it bass ackwards. I thought the head on the rod bottomed out in the plunger and opened the valve when the piston was all the way to the left. I see now that the plunger actually pulls the valve open.
Anyway, I've got other "stuff" to do in life. I think I'll put the mystery aside for a while ( I won't be driving hundreds of miles daily). Maybe I'll get crazy and buy both new cylinders.
Thanks for everyone's input.