CK5
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Hydro clutch swap issue
- Thread starter ntaj*ep
- Start date
I have to believe at this point some pictures of the parts you are dealing with would help a lot.
ntaj*ep
1/2 ton status
Do you know the heights? I have only found one height.. that would be super awesome
Maybe find someone local with a hydraulic clutch and compare the amount of travel?
Here’s what arti says…
throwout bearing lengths
The throwout bearing length for a GM transmission varies depending on the specific transmission type and model year. Here are some general guidelines and measurements:- According to a post on the 1947-1972 Chevrolet & GMC Truck Message Board Network, the throwout bearing length for a 1967-1972 Chevrolet and GMC truck is:
- Old style (longer): 1.875"
- New style (shorter): 1.255"
- Another post on the same forum mentions that the throwout bearing length for a 1965-1972 Chevrolet and GMC truck is:
- 1 7/32" (1.21875")
- A third post on the same forum mentions that the throwout bearing length for a 1967-1972 Chevrolet and GMC truck is:
- 1/2" from the front of the fork to the face of the bearing
- 1-1/2" total height of the bearing from the back of the lip to the face
- A snippet from the “Height dimension of GM throwout bearing” mentions that the tip of the pivot to the front face of the bellhousing or rear face/edge of the block is 4-3/4" without a block saver plate.
- A snippet from “Throwout Bearings” mentions that the throwout bearing has a 1 1/8 in. shaft diameter and a 1 3/8 in. I.D. (inside diameter).
Not trying to do an apples to oranges thing. Even though it might seem that way at first.
When I put the 396 big block and a 1995 NV4500 in my M715. I used the 1995 Chevy master, line and slave. I actually left them intact and removed them from the Chevy as a unit. I then installed them as a unit on the M715. All kind of fabrication for the firewall and pedal to work.
Every thing worked great for 3 years of hard driving. Then one of the springs on the clutch broke and lodged itself into the pressure plate fingers. I decided to replace the master and slave while putting in a new clutch disc.
I had the exact same problem you are. Air was bled out of the line, the throw out arm was moving but the clutch wasn’t being a clutch. Just an ON. I took the transmission back out thinking I had put the disc on backwards or messed up the pilot bearing. Nope. All back together again and it just wasn’t getting enough travel to work.
My then 10 year old son was of course helping me. As we laid under the truck talking about what wasn’t happening he asked me “How does the slave know how far to travel?” I laughed, thought, laughed again and then realized he had a good point. I unbolted the slave, had him push the pedal slowly until the pushrod went as far as I was comfortable. Then he let go of the pedal, I waited a moment and then had to really, really push hard on the slave cylinder to get it back into position. Once bolted down it worked perfect.
Mine was starting too far away from the throw out arm to finish the job. Extending it and forcing it back to a new more forward starting position did the trick.
When I put the 396 big block and a 1995 NV4500 in my M715. I used the 1995 Chevy master, line and slave. I actually left them intact and removed them from the Chevy as a unit. I then installed them as a unit on the M715. All kind of fabrication for the firewall and pedal to work.
Every thing worked great for 3 years of hard driving. Then one of the springs on the clutch broke and lodged itself into the pressure plate fingers. I decided to replace the master and slave while putting in a new clutch disc.
I had the exact same problem you are. Air was bled out of the line, the throw out arm was moving but the clutch wasn’t being a clutch. Just an ON. I took the transmission back out thinking I had put the disc on backwards or messed up the pilot bearing. Nope. All back together again and it just wasn’t getting enough travel to work.
My then 10 year old son was of course helping me. As we laid under the truck talking about what wasn’t happening he asked me “How does the slave know how far to travel?” I laughed, thought, laughed again and then realized he had a good point. I unbolted the slave, had him push the pedal slowly until the pushrod went as far as I was comfortable. Then he let go of the pedal, I waited a moment and then had to really, really push hard on the slave cylinder to get it back into position. Once bolted down it worked perfect.
Mine was starting too far away from the throw out arm to finish the job. Extending it and forcing it back to a new more forward starting position did the trick.
Another thing to look out for is that the pressure plate style can dictate what type of T.O.B. - usually a 3-finger style PP will use a bearing that is flat against the fingers while a diaphragm style PP will use a bearing that has a slightly curved surface against the fingers.
