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Hi all,

I have just regased my aircon on my 68 Riviera after importing to Australia 12 months ago and I noticed the cold air only comes out at floor level.

The vent outlets on the dash are not working at all, even with vent selected.

 

Can anyone suggest were to begin so I can get the dash outlets to work.

 

Thanks Felix

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3 hours ago, mach1 said:

Hi all,

I have just regased my aircon on my 68 Riviera after importing to Australia 12 months ago and I noticed the cold air only comes out at floor level.

The vent outlets on the dash are not working at all, even with vent selected.

 

Can anyone suggest were to begin so I can get the dash outlets to work.

 

Thanks Felix

check the vacuum hose from the back of the carb to the vacuum tee on the fire wall. they are known to become brittle, I suspect you are loosing vacuum,

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 The vacuum controls and AC components are all covered in the '68 Buick Shop Manual Felix.

It's a good investment that will answer questions you haven't thought of asking yet mate !

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17 hours ago, 68RIVGS said:

 The vacuum controls and AC components are all covered in the '68 Buick Shop Manual Felix.

It's a good investment that will answer questions you haven't thought of asking yet mate !

I second Randy's comments. I had the same thing happen on my '68 when I knocked loose my vacuum lines from the back of the AC controller (right control) and then put them back wrong. The Shop Manual is the best way to determine the correct routing for these pesky little vacuum lines.

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I have the 2 shop manuals and I have checked all the vacuum hoses in the engine bay and they are OK.

From the book it appears to be a problem with the heater/aircon mode diaphragm but I cannot seem to locate it.

I did find a diaphragm behind the passenger kickboard is this it?

Also I have a mechanical cable running to the top of aircon box which does not move when any selection is made on the dash,

does any one know what this is for as book does not show it.

Any advise would be appreciated.

Thanks Felix

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2 hours ago, mach1 said:

Any advise would be appreciated.

Thanks Felix

It appears the control head is not connected by cable AND air.

There are two associated and similar appearing diaphragms. One in the cabin in the dash and one in the engine bay.

As stated above, the pneumatic "boot" may have come off the control head.

Here's similar albeit Chevy head with boot shown. Friction fit.

It will take some finesse and patience. All it takes is one unseen split in a line to loose vacuum.

The one attached to my engine bays' diaphragm has partially split twice due to the bad angle.

 

 

$_57.jpg

Edited by PWB (see edit history)

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. . . been a while - I'll have to recheck my manual to see if I can help sort it out Felix.

The  mechanical cable running to the top of the aircon box is the temperature control cable, it may be broken, or the end has come off the control assembly.

The diaphragm behind the passenger kick panel is the outside recirculate diaphragm.

Working on  the heater/AC control can be a P.I.T.A., unless your a part time contortionist !!

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I found a split vacuum line at the canister in engine bay,repaired  and now dash vents and floor vent are working correctly.

I still cannot figure out how the actuator with the mecanically operated cable on air con box is supposed to work, if I disconnect the cable from the mechanism on the box

and move it physically I get hot air in cabin so it is obviously directing hot or cold air via a door in the box. 154269_Engine_Web.jpg.9ae48ca867d215d1bc2b92473ab4392f.jpg

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In post #7, Randy says the mechanical cable is the temperature control cable.  The temperature control should part of a heater hose.  It's allowing or not allowing hot water into the heater core.  The lever on the control panel will probably say TEMP or HEAT. Having no reference, I don't know for sure.  

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On the 2nd gen. Riviera Heater/AC control panels they use thumb wheels Ed to move a cable, no levers.

The mechanical cable controls the open or closed position of the door in the blower and heater box . 

 

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8 minutes ago, 68RIVGS said:

On the 2nd gen. Riviera Heater/AC control panels they use thumb wheels Ed to move a cable, no levers.

The mechanical cable controls the open or closed position of the door in the blower and heater box . 

 

 

A bit wormy

LoL

 

 

Worm.jpg

  • Haha 1

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. . . thank you for the Heater Control Assy pic Mr. Paul, a little bit wormy for sure !

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Looks like a rack and pinion setup. Is a cable attached to the rack part to open and close the air door?

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The cable on the engine bay box is for the heater door and I can see it disappear up behind the control panel.

I cannot get up behind it even after pulling the ducting out.I will give it another go tomorrow.

Also noticed the compressor clutch is now not engaging.With the compressor plug off I have 12 volts but when I connect it 0 volts.

I can get compressor running by jumping it out with the battery.

From the diagram it appears it could be the clutch swich in the dash or the relay.

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14 hours ago, mach1 said:

I still cannot figure out how the actuator with the mecanically operated cable on air con box is supposed to work

Mach1, the left thumb wheel on the AC/heater control panel controls this cable. You may have to try to lubricate the lever on top of the air box to loosen it up. Mine was very stiff at the wheel and lubing this lever helped some. I think the main issues, discussed on another thread, is the fact that the control cables get stuck or sticky within the wire outer coil of the cables and they are very hard to lubricate. Trying to turn the thumb wheel when it is very stiff may lead to breaking the cable anchor at the back of the thumb wheel controller or striping the threads on the controller rod, as seen in the picture above. Be careful and don't force the controls if they offer too much resistance.

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12 hours ago, RivNut said:

Looks like a rack and pinion setup. Is a cable attached to the rack part to open and close the air door?

Yes Ed, the Red side cable  is for temperature control door, the Blue side cable  is for Defroster control door.

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I have got the heater door working on a/con box by spraying some lubricant down the cable.

Vents on dash now working correctly.

Only problem now is  I am only getting 3.7 volts at the compressor when a/c or recirc selected.

Compressor works fine if I power it directly off the battery.

I am thinking the guy did not put enough refrigerant which is causing compressor not to start up.

I will check the wiring out on the weekend.

 

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Thanks everyone for your assistance.

The heater door control cable was kinked just behind the control wheel that is why I could not get full travel.Kink straightened and now OK.

As for the low voltage at compressor I found the clutch control switch in the control panel has a high resistance.Tried spraying it with WD40 and made no difference.

I have now by passed the switch and put a separate switch under the dash.All works great now.

Regards Felix

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