Triumph Repair: TR6 Transmission Issue, clutch release, slave cylinder

Question
QUESTION: I'm restoring a 1972 TR6 and I've got the engine running but I noticed that when I depress the clutch it doesn't seem to disengaging the pressure plate on the clutch.  With the engine running and the clutch fully depressed, I can't shift out of neutral.  When I put more pressure on the shifter the car jumps into gear(I know this isn't great for the drive train)!  I crawled under the car to check that the slave cylinder and push rod were working properly and when the clutch is fully depressed the puch rod moves about half an inch.  I suspect the problem is in the transmission perhaps the tapered bolt that connects the shaft and fork.  Are there any other steps I can take to diagnose this issue before opening up the transmission?

Thanks
Kim

ANSWER: Hi Kim,
The TR-6 is notorious for the problem you are having. Most of the time it is air in the clutch release system. Even when everything is correct you had to push the pedal all the way to the floor to get it to release so it didn't take much to go wrong.
First confirm that the bleeder valve is on top of the slave cylinder and bleed the clutch. Be sure to use DOT 4 not DOT 3 as DOT 3 will melt the seals in the system. After bleeding confirm that the pedal free play is less than an inch at the tip of the pedal. Confirm that the pedal return spring is installed.

Many times when working on TR-6s I found that some had a nut installed on the end of the clutch rod inside of the slave cylinder and have also found some rods that have had a piece welded on to the end to lengthen the rod to take up free play.

I had restored a 72 and did everything I could to get it to release further off the floor. I had installed a new clutch and rebuilt both the master and slave and had corrected the pinch pin in the shaft and still had the clutch grab right off the floor. I finally found that an older master cylinder was a larger bore so I installed it inplace of the one that belonged in the car. A smaller bore slave would work too but I never researched for one.
Here are all of the possible that I have found.
A warped clutch disk.
A loose clutch arm
Air in the system
Bleeder valve on the bottom position and line on top
All moving parts worn just a little each thus making the operating rod too short.
Thrust bearings worn out on the crankshaft allowing the crank to move back and forth. (to test this condition push the clutch in and put a pry bar on the front pulley then release the clutch pedal and pry the crank back towards the back of the car. If you can see any movement that is probably the cause or at least one of them.)

let me know,
Howard




---------- FOLLOW-UP ----------

QUESTION: Thanks Howard,

Before I did the things you suggested, I put the car up on four jacks this morning and turned the starter over with the car in 2nd gear(the clutch was not engaged).  I was surprised to see that the rear axles did not turn.  I tried this in all 4 gears and reverse with the same outcome.

I wonder if I did some damage when the car went into gear without the clutch engaged fully as outlined in my earlier note?

Is there another problem I should also be looking into?

Thanks

Kim
ANSWER: Yes, putting a car into gear when a clutch will not release can brake something. But you need to check a few things first to see if that happened.
How does the clutch pedal feel when you depress it now?
Engine OFF, Transmission in neutral, have some one hold one rear wheel while you try to turn the other rear wheel. Does it turn?
Now put the shifter lever into 4th gear and while someone holds one rear wheel you try to turn the other. Can you turn it?
Let me know what results you get on these tests.
Howard

---------- FOLLOW-UP ----------

QUESTION: Hi Howard,

I checked the things you mentioned with the following results:

-the clutch feels the same as it has since I started restoring he car...it has about an inch of free play at the top and is tight all the way to the floor.  The pressure is very consistent and it feels solid(I haven't bled the Master yet).
-engine off, transmission in neutral-while holding one wheel the other can be turned in either direction
-engine off, transmission in 4th gear-I couldn't turn the wheel while someone was holding the other wheel.  The wheels wanted to turn in opposite directions once the other wheel was released.

What are your thoughts.

Kim

Answer
That's good, nothing was completely broken off anyway. Your description of how the pedal feels means the hydraulic system is probably doing all it can do. So you either have a warped disk or a pressure plate that is not releasing squarely. Providing you checked for end play in the crankshaft like I suggested earlier.
One more test. Put the gear lever into 4th gear with nothing in front of you and hold the brake and the clutch pedal to the floor and hit the starter to see if the engine will start. If it does. Does the car creep forward when you release the foot brake? If it will not start, does the engine turn over with the starter? If not, you probably have a stuck clutch. Normally this requires that the trans and clutch be removed. However, If it has been setting for a long time you may be able to brake it loose. In the dealership we had a lot of stuck clutches back then because a lot of the sports cars would be stored all winter and only brought out in the spring and they would find the clutch stuck.

It requires some skill and a long straight road with no stops and little traffic.

Put the car in 1st gear and start the car. It will take off. Speed up to a speed that you would normally shift to 2nd and carefully bump the gear lever into neutral. Lower the RPM to what you think would be correct for 2nd gear at what ever speed you are moving. Pull it into 2nd gear. Speed up again and bump the lever into neutral again and lower the RPM to what you think would be correct for that speed for 3rd gear and push it into 3rd. and do the same thing for 4th gear. Yes, it does take some skill to do this. Once you are in 4th gear, speed up to as fast as the speed limit will allow and hold the clutch pedal to the floor and quickly open the throttle and quickly let it off and repeat this several times holding the clutch pedal to the floor. If it don't brake loose after 5 or 6 tries you will need to remove the transmission and clutch. I had many MGs and Triumphs do this and I usually got 2 out of every 3 to brake loose this way. The reason you need to use 4th gear is that the maximum strain on a clutch is in 4th gear not 1st.
This is only if you have a stuck clutch not a dragging clutch. If it is a dragging clutch you will need to either do a modify of the bore size of the master or slave or remove the trans to see what is wrong.
I have seen many warped disks due to rough handling of the trans while installing it.
Good luck, let me know how you do.
Howard