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Proper Pressure Plate adjustment M809 series with manual transmission.

Superthermal

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Steel Soldiers Supporter
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Location
Utah, Murray, United States
I am having some issues with the TM on adjusting the pressure plate. My pressure plate that was removed doesn't even come close to the spec (I am assuming here as I am struggling to understand where the measurement surfaces are) and neither does my new one I am looking to mount.
The TM says the distance between the pressure plate ..... ring???top is to be 1.281" but there is no "ring" to measure to and even if this ring is the finished surface on the side of the pressure plate it is not the same "thickness" on the new one as the old one. Also the finger adjustment... and the "top of the pressure plate, that the fingers are to be measured to, where the heck is that spot on the top of the plate? That makes no sense to me.
I will get some measurements for the depth of the pilot bearing in the face of the transmission when I have a sec to see what the compounded distance is to ensure that the bearing will release from the three fingers when in the retracted position. Whomever wrote this section of the TM was drunk. I see no markings on the pressure plate to indicate a "measurement" surface or ring or anything in either of these two spots referred to here:
1749947028687.png
So far this is what I had:
Pressure plate bolt face to the face of the old pressure plate=1.625", New=1.437", TM I think wants 1.281... to the whatever part of the pressure plate...
Old Clutch thickness= .430, New clutch thickness .440
Distance from flywheel pressure plate mounting surface to the clutch face - 1.770 inches
This gives a compression sping load with the original pressure plate of .285 inches.
This gives a compression spring load on the non adjusted unit of.107 inchs.
If I follow the TM for what I think it is asking I would have a negative compression of -0.049"
1749949841793.png
ON this spring load in inches measurement between the old and the new. .285 vs .107. These are my thoughts:
The springs will be at the same compression distance when mounted on the flywheel when in contact with the clutch disc. This is designed into the actual pressure plate and the springs chosen. They only thing that could screw up the clutch not "binding" on the clutch disc is if the plate height was to be adjusted to compress the springs (bringing the plate height up into the pressure plate) so the plate was already compressed higher into the plate than the disc will touch. This would be crappy. And this height is what I would get if I adjusted to the 1.281 distance. I would have a negative distance of .049.
The higher the adjustment distance from the pressure plate mounting face to the pressure plate clutch face only relaxes/releases spring pressure at the extended distance.
Note!: If it plate was too high/extended there could be an issue of not being able to fully disengage the clutch as the plate would just keep extending from its compressed position to what the maximum extended distance would be.
The way I see it if I installed the new pressure plate as it is I would have basically a .107" clutch engagement distance from initial touch to fully engaged and the peddle distance from initial contact to this fully engaged contact would happen over much shorter distance .107" than what I had previously where the initial contact and the fully engaged happened over .285", a peddle travel feel nearly three times the distance between just sllipping and fully engauged. Now my clutch worked perfectly for thousands of miles (The truck has something like 21,000 miles on it) with the height at what you see here in the pics basically a 1 5/8" height from the floor is what I am leaning toward adjusting it to. Same as it was before.
1749947552973.png1749950129097.png1749949744250.png1749950145501.jpeg1749950168666.jpeg1749950184790.jpeg
 
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Superthermal

Well-known member
Steel Soldiers Supporter
357
996
93
Location
Utah, Murray, United States
OK some additional measurements:
Transmission mount face to flywheel's pressure plate mount face=.977
The transmission mount face to the retracted throw-out bearing = 2.033
With the measurements from the pressure plate mount face to the fingers= OLD 2.312 and New 2.327.. This difference may be due to the old one having been work away a bit.. LOL

This means that with the old and the new there is ruffly .294 maximum inches of disengagement of the throw out bearing with the three fingers on the new non adjusted plate and .279 with the old one that was messed up.
That makes me feel better about not ruining the throw-out bearing in this process of having it run all the time and not be able to be disengaged all the way. Now all I need to know is how compressed the pressure plate face is to be when engaged. Since my old one worked just fine with a spring compression of .285 I am thinking I will adjust the new one to be the same as the old one where I will adjust to 1.625 on the bolted contact face to the pressure plate face as seen here:
1000009289.jpg


Any thoughts before I commit and end up tearing this thing back apart because I'm not accounting for something?
 
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