'63 heater airflow problem

[Harry S.]

Re: '63 heater airflow problem

Thanks Harry. I am looking at the AIM. I don't see this part in the heater section. It only shows up in the A/C section. Did this only appear on the latter heater boxes??
Bill

Bill, I see that also. It's part 3839557 (outlet). The only way that part can attach is if there is a rectangular hole cut into the left-end of the heater box. I have seen many heater boxes on eBay (non-A/C) with the cut-out.
I believe the part was used on both A/C and non-A/C cars.

Also, as I look at page 245 of the AIM, is is possible that part was removed and the A/C duct was placed over the left-end of the box?

[Erik H.]

Re: '63 heater airflow problem

Still frustrated here. The shop manual describes the operation of the unit, but not the specifics of the adjustment. Basically says "adjust the Bowden cable". What I can't seem to get past is there looks to be very little adjustment here - the only place I see is the screw where the Bowden cable is mounted.


The bar slides from left to right (towards the passenger side) when the cable is pulled. Given that the defrost flap needs to be up most of the time (in the off and heat positions), I can't see how this can be accomplished with the slide bar configuration. The flaps in my heater box are pretty free-wheeling, so while the bar is able to pull the defrost flap snugly down at the end of the range of the bar, there is nothing to hold it up in the other positions - it just flops right down at anything other than the two extremes of the slide bar (it will stay firmly up when the slide bar is pushed to the left for no heat, and firmly down when the slide bar is pushed to the right for defrost). The issue is the middle position, or first heat detent on the pull knob. When the slide bar moves to the middle when heat is selected on the middle position of the pull, there's nothing to keep the flap from falling down. My slide bar looks like Harry's in the first set of photos in the thread. I have to be missing something here. Thanks for continuing help.

[Harry S.]

Re: '63 heater airflow problem

Erik, you are correct there is very little movement in the adjustment.

Can you take off the radio side panel on the LH side. Remove the Y duct and/or the Snout and with a flashlight and mirror watch what happens when you engage the dash pulls? As I recall one or both of the flaps is spot welded to the cross shaft. Possibly one of your flaps was not spot welded and it has come loose and remains in the closed position no matter what you do?

This picture is after I restored the box and reinstalled it. You can see quite a bit!

[Wayne W.]

Re: '63 heater airflow problem

Still frustrated here. The shop manual describes the operation of the unit, but not the specifics of the adjustment. Basically says "adjust the Bowden cable". What I can't seem to get past is there looks to be very little adjustment here - the only place I see is the screw where the Bowden cable is mounted.


The bar slides from left to right (towards the passenger side) when the cable is pulled. Given that the defrost flap needs to be up most of the time (in the off and heat positions), I can't see how this can be accomplished with the slide bar configuration. The flaps in my heater box are pretty free-wheeling, so while the bar is able to pull the defrost flap snugly down at the end of the range of the bar, there is nothing to hold it up in the other positions - it just flops right down at anything other than the two extremes of the slide bar (it will stay firmly up when the slide bar is pushed to the left for no heat, and firmly down when the slide bar is pushed to the right for defrost). The issue is the middle position, or first heat detent on the pull knob. When the slide bar moves to the middle when heat is selected on the middle position of the pull, there's nothing to keep the flap from falling down. My slide bar looks like Harry's in the first set of photos in the thread. I have to be missing something here. Thanks for continuing help.

There are flat springs to put pressure on at least one of the flaps. I am not sure which or if more than one. Its been a while since I have seen one.

[Harry S.]

Re: '63 heater airflow problem

Post 10, springs on each flap.

[John H.]

Re: '63 heater airflow problem

The bar slides from left to right (towards the passenger side) when the cable is pulled. Given that the defrost flap needs to be up most of the time (in the off and heat positions), I can't see how this can be accomplished with the slide bar configuration. The flaps in my heater box are pretty free-wheeling, so while the bar is able to pull the defrost flap snugly down at the end of the range of the bar, there is nothing to hold it up in the other positions - it just flops right down at anything other than the two extremes of the slide bar (it will stay firmly up when the slide bar is pushed to the left for no heat, and firmly down when the slide bar is pushed to the right for defrost). The issue is the middle position, or first heat detent on the pull knob. When the slide bar moves to the middle when heat is selected on the middle position of the pull, there's nothing to keep the flap from falling down. My slide bar looks like Harry's in the first set of photos in the thread. I have to be missing something here. Thanks for continuing help.

Erik -

Does your defrost door have a spring steel clip riveted to the top surface as shown in the top and bottom images in the attached photo (courtesy Dave Zuberer, I think)? That's what positions the defrost door at the detent positions; if it's missing, the door will just flop free.

[Erik H.]

Re: '63 heater airflow problem

Great pictures John!

I have both side panels removed as well as the Y duct and driver duct. I craned my head up under there, and see only the large clip on the metal side and the tab on the fiberglass side - no sping clip or rivet holes for one. Can you confirm that the spring clip existed on early style boxes? I don't see provisions on the box for where a metal bar would roll under this clip, either, and wonder whether that was a later mod by the factory to address this problem.

I'm thinking of bending out the large clip against the metal box to add more tension. Thoughts?

[John H.]

Re: '63 heater airflow problem

Great pictures John!

I have both side panels removed as well as the Y duct and driver duct. I craned my head up under there, and see only the large clip on the metal side and the tab on the fiberglass side - no sping clip or rivet holes for one. Can you confirm that the spring clip existed on early style boxes? I don't see provisions on the box for where a metal bar would roll under this clip, either, and wonder whether that was a later mod by the factory to address this problem.

I'm thinking of bending out the large clip against the metal box to add more tension. Thoughts?

Erik -

I've never had a '63 box apart - that spring clip may just be a '64-up design; '64-'67 boxes have a cam that moves a shaft between the top of the door and the bottom of the clip to move the door and set the detents.

[Harry S.]

Re: '63 heater airflow problem

Erik, I know it's difficult for you send pictures as your box is in the car. To help, what is the VIN sequence number of your car. I have many photos of boxes that I restored and I'd be happy to send you them if close to what I think was in your VIN.

Send me a PM.

Cheers