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TR6 Clutch Problem

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Govtslug

Govtslug

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Hi everyone-

My clutch suddenly stopped disengaging today. It’s a 1970 TR6 with a Toyota 5 speed. Probably about 4000 miles since the transmission was installed. Everything was working fine, took off from a stop light, tried to shift into 2nd gear and it wouldn’t go. Pumped the clutch a few times, finally went in. Shifting into 3rd and 4th was difficult, and when I pressed in the clutch while in gear it only partially released. Limped home. It has fluid in the master, and the clutch feels ok. Does that sound like a master problem? I’m not sure what the slave is like, is it Toyota or Triumph?

im looking at master cylinders and there is a .70 or .75 bore. Change over was 1970, so I’m not sure which one I need. The one on the car is a TRW with the number 541 104 stamped on it, but I can’t seem to find that number on the new TRW masters. Does anyone know?

Thanks!

Tom
 
The VanDenakker slave is inside the bellhousing. This is why the Eagle Gate Kit is better
Mad dog
 

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I need to get under it today to see if I can find the slave on the outside. Do you think it’s more likely a slave problem or a master problem? I guess if the slave is inside the bell housing I need to remove the trans to get to the slave? Ugh.
 
Govtslug said:
I need to get under it today to see if I can find the slave on the outside. Do you think it’s more likely a slave problem or a master problem? I guess if the slave is inside the bell housing I need to remove the trans to get to the slave? Ugh.
Click to expand...
The HVDA conversion use a hydraulic throw out bearing. Look to see if you have hydraulic lines going into the bell housing and you will know for sure.
 
Maybe unrelated, because it happened to me with my Austin Healey Sprite recently ... with reconditioned gearbox mounted. Long story short, after they disassembled almost everything the most unobvious thing had happened. In the factory-new clutch assembly, 2 of the 3 bolts with which the levers for the pressure plate were supposes to be mounted had loosened, so the clutch disk never fully released.
 
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On the earlier HVDA conversions he used a throw out bearing that required regular brake fluid, NEVER silicon. Silicon would kill the O ring inside the unit. I am not familiar with the latest version.
You still can bleed the system if needed.
Your problem sounds more like a master cylinder problem. I would start there.
Charley
 
Update: I replaced the clutch master and everything seemed ok. Then after a short test drive it happened again - clutch didn’t appear to disengage, and after popping it into neutral it wouldn’t go back into gear. I turned the screw behind the clutch pedal to allow the pedal to travel further (about 1 turn), and it went into gear. Then the next day it happened again. Maybe my problem is as simple as turning that screw down farther? How far can I turn that screw down before I start having problems with the pedal extending the clutch too far?
 
Govtslug said:
Update: I replaced the clutch master and everything seemed ok. Then after a short test drive it happened again - clutch didn’t appear to disengage, and after popping it into neutral it wouldn’t go back into gear. I turned the screw behind the clutch pedal to allow the pedal to travel further (about 1 turn), and it went into gear. Then the next day it happened again. Maybe my problem is as simple as turning that screw down farther? How far can I turn that screw down before I start having problems with the pedal extending the clutch too far?
Click to expand...
My recommendation is to first try to bleed the clutch system. There may be some air in the system.
If no change then try moving the bolt.
( I assume you are referring to the bolt mounted to the floor underneath the clutch pedal).
Be careful about moving the bolt very much. I remember the warnings about being able to push the bearing to far could make bad things happen.
Charley
 
Thanks. I’ve bled the clutch and it feels firm. At this point, I don’t think I have much to lose if I back the bolt off a little more. If it doesn’t work, it must be a problem with the slave or throwout bearing. And that would require taking the trans out, which i really don’t want to do. if I back off the bolt too much and cause bad things to happen, then I will also need to remove the trans. Any way to know how far I can turn that bolt down before I cause problems?
 
Govtslug said:
Thanks. I’ve bled the clutch and it feels firm. At this point, I don’t think I have much to lose if I back the bolt off a little more. If it doesn’t work, it must be a problem with the slave or throwout bearing. And that would require taking the trans out, which i really don’t want to do. if I back off the bolt too much and cause bad things to happen, then I will also need to remove the trans. Any way to know how far I can turn that bolt down before I cause problems?
Click to expand...
I am not at home until Tuesday. I have the set up instructions there. I have had 3 of these in place now for an average of 10 years each. Never had to change the pedal position. I did get one bearing to close and had to remove tranny and reset the bearing back a bit.
I assume you do not have the info of how to set it up initially. I suspect that tells me what you need to know.
I would think about 1/8" at a time would be safe. My best guess.
How far does the pedal travel to reach the stop bolt at this time?
Charley
 
The pedal is 3/4 inch from the bolt
 
oops, I mismeasured it, it is about 1 3/8 inches from the head of the bolt to where it touches the clutch arm. The bolt only sticks out about 1 1/2 inches, so I wouldnt be able to get three inches even if I fully took the bolt out!

IMG_0419.jpeg
 
Govtslug said:
oops, I mismeasured it, it is about 1 3/8 inches from the head of the bolt to where it touches the clutch arm. The bolt only sticks out about 1 1/2 inches, so I wouldnt be able to get three inches even if I fully took the bolt out!

View attachment 92676
Click to expand...
If you are willing to wait until Tuesday I will then be better able to advise you.
Charley
 
That would be great, thanks! Meanwhile, I’m going to back the bolt off a little more and see if it helps.

Tom
 
Govtslug said:
That would be great, thanks! Meanwhile, I’m going to back the bolt off a little more and see if it helps.

Tom
Click to expand...
Tom,
I just checked my two cars and what I got was -----1) the pedal is about 2 &3/8" from the stop bolt. The first 5/8" is slop or travel in the linkage before I feel any resistance. Then there is about 1&3/4" of travel with resistance.
2nd car)--- The pedal is 2" from the stop bolt. Then about 3/8" before I meet resistance. That leaves about 1&5/8" of travel with resistance.
With that said my 3-4 "of pedal travel was wrong.

Reading from the installation instructions here are the three steps they give.
1) Park vehicle on slight incline so that when clutch is fully released, vehicle will roll.
2) Depress clutch pedal slowly until vehicle starts to roll, indicating that the clutch is disengaged. At that point, set the brakes.
3) Accurately measure the distance between the pedal and the firewall, and adjust travel stop so pedal does not exceed the distance of full clutch release. It is the travel after disengagement that will cause seal rupture on installations that have excessive pedal travel.

As each of these cars may be set up slightly different. Meaning the distance between the throw out bearing and the clutch fingers is variable . The distances of pedal travel will be affected likewise.
I believe that if you wish to adjust the stop bolt use the steps above. That should keep you safe from harming the throw out bearing seals.
If you determine that you need to actually remove the tranny and set up the throw out bearing once again and need more info on the intial installation let me know.
Charley
 
Thanks Charley! I’ll give it a try, although getting the measurement right while I’m trying to hold the clutch pedal in place might be tricky…

Another measurement I checked was the distance of the clutch master cylinder rod when I fully pressed in the clutch against the stop bolt. The rod has about another inch of potential travel (if I did something crazy like removed the stop bolt - which I won’t do!) before the fork end of the rod would touch the rubber gasket. Would you be able to check how far the fork on the end of the rod is from your rubber gasket on the floorboard when you have your clutch fully depressed? I’m just curious if you are moving your master cylinder rod more than I am. Thanks again!

Tom
 
Govtslug said:
Thanks Charley! I’ll give it a try, although getting the measurement right while I’m trying to hold the clutch pedal in place might be tricky…

Another measurement I checked was the distance of the clutch master cylinder rod when I fully pressed in the clutch against the stop bolt. The rod has about another inch of potential travel (if I did something crazy like removed the stop bolt - which I won’t do!) before the fork end of the rod would touch the rubber gasket. Would you be able to check how far the fork on the end of the rod is from your rubber gasket on the floorboard when you have your clutch fully depressed? I’m just curious if you are moving your master cylinder rod more than I am. Thanks again!

Tom
Click to expand...
The rod is 1&1/2"from the front of the boot to the front of the fork. On both cars the rod moves about 1/2 of the distance or 3/4". Attached is a photo. The rod is rubbing on the boot. So you can see the black on the rod showing the movement.
Charley
 

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Charley, I really appreciate your help. I turned in the stop bolt another turn, the throw on the master cylinder rod is now closer to moving about half the distance to the rubber boot. I drove it this morning and it shifted fine. Let’s hope it stays that way!

Tom
 
Have you tried the first two steps in the 3 step process?
By having the bolt already in place there is no need to measure. You might be able to move the bolt even further. You should make sure that you are getting the clutch fully disengaged when the pedal is fully down. Otherwise you will be getting excess wear on the clutch and flywheel anytime you have the car at a stop with the tranny in gear.
Charley
 
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