TR2/3/3A Wrong slave cylinder

[carpecursusII]

I have a TR3 with a TR6 gearbox. When I did the conversion is followed the recommendation to shorten the slave cylinder push rod by about 1/4 to absorb the change in mounting position. I have driven the car about 100 miles and did not like how it shifted, the pedal engaged very late and it seemed that it was barely engaging enough for good shifting. I crawled under the car today to do some adjusting and after reading some posts and looking at pictures I now know I have a tr6 slave cylinder that is mounted on the engine side of the mounting bracket. I can go try and find a tr3 cylinder and hope that it is good but what would happen if I mounted the cylinder on the transmission side of the bracket, adjusted it properly and drove away? Would the concourse judge notice?

 

[TR3driver]

Not likely any judge would crawl that far under the car; and if they did, they'd notice the "wrong" gearbox.

OTOH, I doubt that changing the mounting position is going to help, as long as you already have it adjusted properly.

 

[karls59tr]

Not likely any judge would crawl that far under the car; and if they did, they'd notice the "wrong" gearbox.

OTOH, I doubt that changing the mounting position is going to help, as long as you already have it adjusted properly.

While we are on the subject: My TR3 has always had the 4A clutch MC that the PO had installed. Years ago I installed a TR6 gearbox and did not have any issues with the setup. Recently I had to change out the MC rod end"fork" as the pin hole had ovalled out. I installed a new fork but am now having trouble getting the right adjustment on the MC rod to make things work properly. How would 4A MC rod length compare with TR3 MC rod length and to complicate the issue how would having a TR6 trans affect the slave cylinder rod length? Maybe I should be asking"How do I start from scratch to get this setup adjusted with the 4A MC?" I was thinking of going back to a TR3 MC to make things easier:confusion:.

 

[TR3driver]

While we are on the subject: My TR3 has always had the 4A clutch MC that the PO had installed. Years ago I installed a TR6 gearbox and did not have any issues with the setup. Recently I had to change out the MC rod end"fork" as the pin hole had ovalled out. I installed a new fork but am now having trouble getting the right adjustment on the MC rod to make things work properly. How would 4A MC rod length compare with TR3 MC rod length and to complicate the issue how would having a TR6 trans affect the slave cylinder rod length? Maybe I should be asking"How do I start from scratch to get this setup adjusted with the 4A MC?" I was thinking of going back to a TR3 MC to make things easier:confusion:.

Is it a clutch MC (.75" bore) or a brake MC (.70" bore) ?

I don't know how the lengths compare, but the MC pushrod length should not be critical at all unless you have the old pedal stop installed. With the pedal stop, the important bit is that it still leaves some end play (.010" is the factory number IIRC) when the MC piston is fully out against the stop. Other than that, all the MC pushrod length affects is the pedal position. (As you probably know, the original 4A pushrods were not even adjustable.)

The gearbox should only affect the clutch to the extent that the thicker flange moves the clutch slave mounting position around. But if the MC clevis was worn out, there might be wear in other places as well. The TR6 made no provision to lubricate the bushings that the clutch operating shaft rides in, which seemed silly to me. I converted to the early brass bushings and added grease zerks to mine.

At the slave, you get two choices. With the TR6 arrangement, don't use a return spring and make sure there is a spring inside the slave, trying to push it out. Many books don't show that spring, but it is important.

But if you want to keep the TR3 arrangement, of course you don't want the internal spring and need the return spring in good shape so it actually pulls the piston home every time. I had to modify the mount for mine to get reliable return action. You'll also need the adjustable pushrod of course. I use the TR3 arrangement, but I like to keep the pushrod adjusted quite a bit tighter than the factory spec, so I get a higher clutch pedal. Here again, the only important aspect is that there is some freeplay under all conditions. Anything more than that is just to allow for wear in the clutch. (The gap will close up as the friction plate wears. If it closes entirely, the slave will start holding the pressure plate off the disc, allowing the clutch to slip.)