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1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks Discuss the Early Eighties Bullnose Ford Truck

C5 kickdown rod

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Old Jan 22, 2019 | 04:24 PM
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C5 kickdown rod

Trying to settle an argument, I say the kickdown rod controls line pressure and shift points, my friend says it doesn't. Which of us is right?
Also was looking under the hood of my '84 F150, and the hose from the modulator running into a plastic vacuum tee on the firewall. Wouldn't there be a better vacuum source at the intake manifold?
 
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Old Jan 22, 2019 | 04:49 PM
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Originally Posted by 1981 F100
Trying to settle an argument, I say the kickdown rod controls line pressure and shift points, my friend says it doesn't. Which of us is right?
Also was looking under the hood of my '84 F150, and the hose from the modulator running into a plastic vacuum tee on the firewall. Wouldn't there be a better vacuum source at the intake manifold?
A TV rod controls line pressure and shift points. A kick down rod just kicks the trans down a gear at or near full throttle application from cruise.
The C5 uses a kick down rod, not a TV rod.
 
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Old Jan 22, 2019 | 06:23 PM
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Originally Posted by matthewq4b
A TV rod controls line pressure and shift points. A kick down rod just kicks the trans down a gear at or near full throttle application from cruise.
The C5 uses a kick down rod, not a TV rod.
Yep, mine is a C5. Wonder if I could move the vacuum modulator line to the vacuum tree at the intake manifold, instead of where it is now?
 
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Old Jan 22, 2019 | 07:02 PM
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Originally Posted by 1981 F100
Yep, mine is a C5. Wonder if I could move the vacuum modulator line to the vacuum tree at the intake manifold, instead of where it is now?
To me vacuum is vacuum be it on the manifold or a vacuum tree, that's what that is call on the firewall you must have factory AC, or if you ran a line to the back of the truck.
But if it makes you feel better give it a try.
Dave ----
 
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Old Jan 22, 2019 | 07:05 PM
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Originally Posted by 1981 F100
Yep, mine is a C5. Wonder if I could move the vacuum modulator line to the vacuum tree at the intake manifold, instead of where it is now?
Where is it now ? It should be on the vacuum tree on the intake or the vacuum distribution manifold fed by the intake.
The C5 is the same transmission as the C4 but with a lock up torque converter.
 
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Old Jan 22, 2019 | 09:27 PM
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Originally Posted by matthewq4b
Where is it now ? It should be on the vacuum tree on the intake or the vacuum distribution manifold fed by the intake.
The C5 is the same transmission as the C4 but with a lock up torque converter.
It is hooked into a small black vacuum block that is mounted on the upper firewall.
 
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Old Jan 22, 2019 | 09:28 PM
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Originally Posted by FuzzFace2
To me vacuum is vacuum be it on the manifold or a vacuum tree, that's what that is call on the firewall you must have factory AC, or if you ran a line to the back of the truck.
But if it makes you feel better give it a try.
Dave ----
It HAD factory AC, but not anymore since I removed it
 
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Old Jan 22, 2019 | 09:52 PM
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Originally Posted by 1981 F100
It is hooked into a small black vacuum block that is mounted on the upper firewall.
That is equivalent to manifold vacuum if you want move it to the intake as this will give you a more true signal especially if something else on that block is leaking badly. But generally it should not make a difference.
 
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Old Jan 22, 2019 | 10:11 PM
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Originally Posted by matthewq4b
That is equivalent to manifold vacuum if you want move it to the intake as this will give you a more true signal especially if something else on that block is leaking badly. But generally it should not make a difference.
Ok thanks. I also observed the modulator line was rubber all the way from the modulator, to the vacuum block on the firewall. I assumed it was a steel line ( it was on the 81 I had)
 
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Old Jan 22, 2019 | 10:31 PM
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Originally Posted by 1981 F100
Ok thanks. I also observed the modulator line was rubber all the way from the modulator, to the vacuum block on the firewall. I assumed it was a steel line ( it was on the 81 I had)
It should be metal all the way with rubber line connections to the modulator valve and the vac source.
If it is rubber all the way there is good chance it is collapsing under vacuum and screwing things up.
 
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Old Jan 22, 2019 | 10:38 PM
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Originally Posted by matthewq4b
It should be metal all the way with rubber line connections to the modulator valve and the vac source.
If it is rubber all the way there is good chance it is collapsing under vacuum and screwing things up.
Yes it is a rubber line all the way, feels like windshield washer tubing. I'll go get a piece of metal brake line and make a new one. I think they were 5/16" or 1/4"
 
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Old Jan 22, 2019 | 11:31 PM
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Originally Posted by 1981 F100
Yes it is a rubber line all the way, feels like windshield washer tubing. I'll go get a piece of metal brake line and make a new one. I think they were 5/16" or 1/4"
1/4" OD is all you need that would be about 3/16" ID no need to to go any bigger than that.
 
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Old Jan 23, 2019 | 06:18 PM
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I moved the hose to the intake manifold, and it made a world of difference. there was metal line in place, I just didn't see it.
 
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Old Jan 23, 2019 | 06:33 PM
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Originally Posted by 1981 F100
I moved the hose to the intake manifold, and it made a world of difference. there was metal line in place, I just didn't see it.
Check to make sure something on the distribution manifold is not leaking or that it is not cracked. As it should not make difference.
 
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Old Jan 24, 2019 | 04:40 PM
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Originally Posted by 1981 F100
It HAD factory AC, but not anymore since I removed it
Even if it does not work the controls still need vacuum to operate the zone doors, defrost / dash vents / floor.

Originally Posted by matthewq4b
Check to make sure something on the distribution manifold is not leaking or that it is not cracked. As it should not make difference.
Yes do so. Because he has AC and I cant remember were the vacuum tank gets it's supply from. Check the tank / metal juice can for leaks, mine had rusted pin holes so the motor had a vacuum leak.
Dave ----
 
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