Heater knob problems...

[poopdevil]

Anyone know exactly what goes on when you turn the heater knob?
I recently reconnected my heater flaps to the cables. I replaced the pin in the handle and started turning it..If I didn't also turn the threaded piece under the handle the handle would want to resist my turning...I was able to get the flaps to raise but then today when I lowered them and tried again ...it was popping and then went real loose..I twisted the metal threaded piece until I pulled the unit out and behold the cable was snapped..
What is happening inside the tube holding the cables while turning...I need to figure this out so I can fix it properly..Is there a diagram out there?
I replaced my heater boxes and flaps so its all new.
It cant be that hard and I don't understand why it snapped while turning it..the cables are not rusty or anything but had a lot of resistance.

thanks in advance

[RareAir]

The heater control assembly acts like a turn buckle. There is an outer sleeve, inside resides a threaded insert. The threaded insert travels up/down inside the sleeve depending on direction of rotation of the control knob.

When you twist the knob to close the flaps (heater on), the threaded turn buckle pulls the cables tight. This will effectively shorten the length of the cable, pulling the flaps closed and forcing the heat from around the cylinders into the cabin.

Twisting the knob to open the flaps (heater off) will allow the cable to slacken and sit in its 'rest' position.

When you installed the cable, are you aware that one side of the cable is longer than the other? Be sure to put the cable lengths inside their proper holes
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1947 Typ 11a
1954 Typ 117
1956 Typ 151
1959 Typ 117
1959 Typ 265
1961 356B
1966 Typ 151
1966 Typ 241

[poopdevil]

Cables were already installed so I didn't know one was shorter. Why would it have snapped do you think? Is there a diagram out there? When turning does the cable wrap around the sleeve as you turn it?

[EVfun]

[Snort]

Here's a page from the service manual showing the pieces if it helps any.

[poopdevil]

Ahhh. Thanks so much...I am wondering what snapped the cable..literally both sides broke and left a tine U shaped bit left attached to the unit..
Thanks for the Diagram. I am going to take it all apart and clean it and re grease and add new cables and see what happens.

[jason]

Make sure it turns really easy while apart. If it is tight it will twist the cable instead of pulling.

[poopdevil]

That's the problem I think. I took it out and will be messing with it soon. Pretty sure the inner screw is jammed and the whole unit was turning.

[Snort]

I remember another person having this problem a few years back. In that case the locating pin inside the tunnel was broken off allowing the #5 in the drawing to spin.