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TR2/3/3A TR3a Clutch cylinders

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L

Lemlem

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Hello everyone, On my car the master cylinder has a .75 bore and the slave cyl has a 1 inch. Shouldn't it be the other way round?
 
Nope, that's right. Why do you want to reverse it?
 
Try thinking about the brakes: The diameter of the master cylinder vs the diameter of the pistons in the calipers.

Like using a lever -- you position the fulcrum to turn a lot of movement into a little movement.
 
Thank you for the responses BUT, "like a lever" a lever works by leverage advantage, ie A long handle and a small pivot. It seems that if the m?cyl is smaller then the volume of fluid entering a larger cylinder will not push it as far! It seems like it should be the other way round,NO!
 
Are there any other comments on this. What I'm trying to say is; if a Master cylinder has a bore of 3/4" and it is operating another cylinder which is 1" then for 1" of movement of the master the fed cylinder can only move 3/4" as it needs more fluid to occupy the 1" diameter. Conversely, if a 1" cylinder fed into a 3/4 the 3/4 piston would have to move farther!
 
Well, the math is a bit off, you need the ratio of the two volumes, not just the diameter.

But you are right, a larger piston pushing a smaller slave will result in more movement at the slave, the opposite will result in less movement, but with a mechanical advantage.

But that doesn't mean the sizes the Triumph engineers selected are wrong, and of course other parts of the linkage (clutch petal, the arm that operates the fork) also affect the system.
 
Yes, I agree, I was just generalising the dimensions. Well, here is the issue, the clutch pedal needs 2 pumps before it will fully operate and I have bled it properly, adjusted the slave rod as per the book 1/10th" play. It was just the same when I started!
 
Check how far the slave moves for one stroke of the pedal. If it is less than about 5/8", there is a problem in the hydraulics. (My guess would be a broken spring inside the MC, but there are lots of other possibilities including not having the pedal properly adjusted.)

If it is moving that much (and you do have it properly adjusted), then there is a problem inside the bellhousing.

Oh yeah, also check that the return spring is, in fact, returning the slave piston all the way to the internal stop. A weak or ineffective return spring can also cause odd problems.
 
Darrell_Walker said:
Well, the math is a bit off, you need the ratio of the two volumes, not just the diameter.
Click to expand...

JIC anyone is wondering, it's actually the ratio of the piston areas.
 
Thank you, when you say pedal adjustment, both pedals are at the sme height is there a different adjustment?
 
TR3driver said:
Darrell_Walker said:
Well, the math is a bit off, you need the ratio of the two volumes, not just the diameter.
Click to expand...

JIC anyone is wondering, it's actually the ratio of the piston areas.
Click to expand...

Randall is of course correct. I was thinking about that there is an equal volume of fluid displaced, but the mechanical advantage (or disadvantage) of the hydraulic potion of the mechanism is the ration of the areas.
 
I appreciate the input from everyone, if anyone knows, what is the recommended process for adjusting the Master cylinder rod.
 
Nope, drivers seat is always fixed. Only the passenger side folds forward, even on RHD cars.

PS, it's good practice to start a new thread when you have a new question. Lets folks decide if they are interested in reading by the title, and makes it easier to find later on.
 
Thank You, Yes, I realized that afterwards. I clicked on New reply instead of New post. As for the clutch issue, I ended up modifying (shortning)the push rod then removing the very strong spring, I pushed the piston all the way out then adjusted the free play on the rod. I added a very week spring just to ensure the lever would in fact come back. It is perfect. I presume that someone fitted the wrong cylinders, I ordered the correct ones and of course they were not going to work! Thank you all.
 
My experience with the Âľ master cylinder and 1 inch slave was resolved when I put in a Âľ slave. What I found was that it took a lot more leg pressure to push the Âľ slave, so I rebuilt the 1 inch slave and found the car much more comfortable to drive.
 
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