Old Air A/C installation.

[ddsmith]

Several board members requested I post this information here. So here goes. The first part will be a bunch of night time pictures taken of the truck following the installation. I will follow that with the initial information I provided cali_surfer because he wanted some details. I will then provide information specific to the install since it's still relatively fresh in my mind. If you have specific questions that I am not answering then you can PM me and I will do my best at answering to the best of my knowledge. The disclaimer is I have no relationship with Old Air Product other than I purchased on from GMC Paul and this is my experience with it. Let's get started.

Additional photo in the next thread do to number of image limits.

This is exert from the info I sent cali_surfer.

How about I start you off by telling you what you can do even before the unit arrives. Take your glovebox out. If the truck isn't driven daily and you know when the unit will arrive then here are some other great get them out of the way things to do. Remove your heater and ducting on the inside of the truck. Remove all of your duct hoses. You get new ones in the kit. Remove the firewall side ducting/(evap) if the truck originally had A/C. Remove the bumper and grill. Boy it looks funny like that. Remove the heater control panel. You'll need it out for the installation. Remove the cables from the control panel. You sort of need to do this to get the control panel out. Remove the radio to allow access for running duct hoses. Remove ashtray, actually needs to come out for heater control panel removal. I was thinking it probably does not have to come out but hey it four screws.

The only thing you reuse is the control panel and the vent outlets. Everything else is pretty much included. Don't buy anything thinking you may need it because you'll probably be ripping it out. I posed that same question on the board because I was thinking about fixing the hi speed relay and someone replied not to bother. They were right if I had fixed it I would have been throwing money away. All of the vent doors and other stuff related to the original come out with the heater and evap removal with the exception of the damper on the passenger side kick panel and the cowl area on the passenger side. Neither one is needed for the Old Air unit to function. In fact they recommend the doors stay shut to reduce outside air in the cab. The one on the kick panel stays closed without vacuum. Just pull the hose and your set on that one. The one in the cowl area I'm still trying to figure out. I believe it is normally open with no vacuum but can't see it well enough to make sure. I currently have the hose removed from that one also. If it is closed with vacuum it's easy to make it that way with the engine running. Just plug the hose into the fitting were the original vacuum reservoir tapped off the intake manifold. The vacuum can gets removed. It has two lines. One comes from the manifold and one that feed a valve on the A/C and heater control panel. During removal of the panel you will see three vacuum lines hooked up to a three port valve. It doesn't look like a valve but that is what it is. Those hoses get pulled and discarded. The new setup uses two cable controls. One controls the defost damper and one controls the heater flow control valve that they provide in the kit. In addition they provide a cutoff valve to totally stop coolant flow in the summer to prevent defeating your A/C system cooling ability. They provide the new cable so you can scrap the old ones when you pull them out but if your like me you'll keep them until done. You never can tell when they may be useful.
I'll do a quick run through of the installation. The control panel gets modified first. The kit comes with a microswitch which allows the compressor to operate. This gets mounted to the control panel with two screws or pop rivets. The instructions say drill to 1/8 " pilot holes. All I'm going to say is you decide what size holes you need to drill. I ended up using the pop rivets because I don't plan on taking it apart. Just make sure the switch is positioned so that the switch is made up when the control lever (the cold/hot one) is in the cold position. Do not reinstall the control panel. Wait until later when the cables get installed.
I moved then to the unit installation. The A/C and Heater unit is a box with four tubes coming out one side and three nut looking thing installed on that side. There is a plate that goes on the inside of the firewall and a plate that mounts on the outside of the firewall. They eventually get bolted together and sandwich the firewall. Here is were you'll need some kind of cutoff wheel or sawall. The firewall on my truck had a raised lip on the openings on the inside of the firewall. That raised lip has to be removed and some additional material needs removed because it interfers with the tubes that must passed through the firewall. I used a plasma cutter which made it alot easier. The instructions said I would need to enlarge some bolt holes on the firewall and that wasn't necessary. Once the firewall is modified put the inside and outside plates together sandwiching the firewall and check for fit. Pull the inside plate back off and mount the unit to the plate with the three 1/4" X 3/4" bolts provided. Don't overtorque or you'll pull the nuts out. Remount the inside plate and mark the drain location on the floor of the cab below the unit. I had to pull back my floor mat for this. They say to drill a 1 1/4" hole in the floor for the grommet. My grommet was so stretched out because some dummy folded the hose and put it through the grommet streching it out of shape. I chose to drill a hole that was just a small bit larger than the drain tube and seal it with RTV. I'm pretty sure I used a 5/8" drill for this operation. So with the unit out drill the hole. Attach the hose to the unit. You can do this a couple of ways. I chose to attach it to the unit and work it through the firewall during the inside plate reinstall. You could try and put it on after the inside plate is installed with the unit attached but I didn't want the pain. Once the plates are installed( don't forget the ground wire) then move to the outside of the cab.
There is a four hole grommet that needs to go on over the four tubes coming through the firewall and then worked into the engine compartment firewall plate opening. I used dish soap to lubricate it so I could get it over those fittings one at a time. Then I worked it into the opening. Make sure the caps are tight on the A/C lines so you don't get dishsoap in the freon lines. That would be the two on the left looking at the firewall. I think I'll go for now but I'll give you additional installment of the installation. Talk to you later.

I'm editing this to provide some of the stumbling or slow down things that happened in addition to what was already mentioned above and I broke them out so that if you already read above you could just look here.

There was suppose to be a decal that get put on the new control after you modify it to identify what everything does. My kit didn't come with a decal. I figured I don't need it anyways because I know what the levers do. It would sure goof up someone if I let them borrow my truck. Hey wait I don't have to worry about that because no one borrows my truck.
The instructions for inserting the thermostat probe in the evaporator core were confusing. They made a big deal about were on the core to insert the probe and they had a bullseye attached to the core to show where to insert it. The diagram shows the probe going straight in and the instruction said insert it at a 45 degree angle. This is obviously to allow insertion to 2 inches in depth and to not run into an evaporator tube. You'll see when you get there. This can be done as soon as you unpack the unit if you chose.

[ddsmith]

This is installment two in a series of how many it takes to describe the installation.

One of the items that would be nice to get out of the way would be duct hose installation. To start with, if your truck originally was air equipped, this particular piece of information may make you happy. My kit came with a center vent that you could install on a truck without A/C originally but it only has one inlet port. I started looking at it and looking at my original center vent and determined that I liked the distribution(two inlets) of my original vent and the front piece on the new vent. I was able to remove the chrome front of the new vent and place it on the old back piece. This gives it the best of both worlds. Two defrost hoses get run from the units oblong duct to the defrost ducts. A oblong Y distributor is used to allow this hookup. The driver side defrost hose routes above the radio area. If your truck was not an original A/C truck you'll have to cut openings in the dash center section and also were the driver and passenger side A/C vents need to go. I can not comment on the two side vents because mine were the original ones and no other side vents were supplied in my kit. With the defrost hose hooked up move on to the A/C vent hoses. Place adapters over original A/C driver and passenger side vents. Route the hoses as required to the 4 round outlets on the top of the A/C unit. Two of these hoses will route to the center vent if using the original center vent or modified new vent. You'll only have three hoses if using the new center vent. They supply a cap to install to one of the four ducts at the top of the unit if only three hoses are used. Make sure when routing hoses that you take into consideration the defrost cable must route to the defrost damper on the drivers side top of the unit, but isn't installed yet. Once this routing is complete you may wish to reinstall your radio. Leave the ashtray and vent control out until later.

Now we can move back to the outside. Let's work on the compressor install a little. The bracket supplied comes with a caution that they will not accept a return if it has been painted or plated. Test fit prior to painting. So how about a little check. The big problem would be you got a left versus right side mount. I just eyeballed how it was to hook up and painted the bracket. Once the bracket is dry you can install the bracket in place. This requires removal of two water pump bolts and two intake manifold bolts. Installation is relatively easy. The kit said to get between a 54 and a 55" belt. I got 54.5" and it turned out to be to long. Fortunately for me I also got an alternator belt which was 53.5" and that worked great for me.

The next part of the installation is the condenser and drier. If you have an original A/C truck you may run into a little trouble trying to install the condenser. I chose to use the original holes for mounting the condenser. The problem was that the bottom holes are in a very difficult location to allow access without ripping out the shroud, radiator and etc. I'm a little on the lazy side and didn't want to do that so I taped a nut and lockwasher on a piece of wire. I used welding filler wire but any straight stiff piece of wire will work. I installed a bolt through the hole and lowered the nut and lockwasher on the wire to hold it to allow engagement of the nut. Then I was able to hold the nut with my hand while tightening the bolt. If you have a none A/C truck you attach the condenser with self tapping machines screws. That's why it's easier. With the condenser mounted, you can move on to the drier. The drier gets attached loosely to the front of the core support on the passenger side of the condenser following the directions supplied. Install the aluminum line from the condenser to the drier. Make sure to use lubricated o-rings at the joints. The lube which is refrigerant oil is supplied in the kit in white tubes which are not marked. Now comes the fun part. There is a opening in the core support between the drier and the condenser. It is about two inches in diameter and needs to have a grommet installed. If the truck was original then I would just pulled the original one out and slit it to allow tube installation, place the aluminum tubes in the grommet and reinstalled it back in place. The killer grommet piece is the one that gets installed under the front of the battery tray. It is very difficult to get the grommet installed in the space that is available. It needs to be installed to prevent the aluminum lines from being chaffed on the steel. This is probably more important if the original grommet is not used. You can now connect the aluminum lines which come through the grommet to the condenser and drier. With the proper lubricated o-rings. I had a small problem here because the picture they supplied did not match how the lines needed installed. I needed to bend the aluminum lines a small amount to provide adequate clearance to prevent tubing wear at the upper condenser fitting. The next step involves installing the support bracket to the battery tray. If you have an A/C truck this bracket is already installed. If not, using the supplied template mark the battery tray and drill as required to attach. Make sure that the aluminum A/C lines are not punctured by the drill. Install the pressure switch in the aluminum line with the port. Now install the tubing support bracket to the mounting plate. Well I think that's it for this installment.

[ddsmith]

This is the third and hopefully last installment of the installation. So far we've got most of the inside work accomplished and a big chunk of the outside work done. The light at the end of the tunnel is near. It's time to run the A/C hoses to get the freon side of the system closed up. The kit comes with a TXV(thermostatic expansion valve) that needs to be installed on the bottom left(looking from the front of the truck) line coming through the firewall. Again you need to use the appropriate lubricated o-ring when installing the valve. The top of the valve has a dome on it with a line coming out of it. This is the sensing line and needs to be install on the upper line. There is a special clip that comes with the kit to allow attachment. The important part of placing this sensing tube is that you take care with it and gently bend it so the pigtail looking part is parallel with the upper tube and then clip it to the upper tube. The next thing to do is take the refrigeration tape(sort of a sticky black spongy tape and wrap the clip and upper tube and continue wrapping the sensing line all the way back to the dome of the TXV. When this is complete you'll have three refrigeration hoses that need installed. One hose is installed between the liquid line outlet of the condenser(hi pressure liquid line) and runs to the TXV you just installed.
Caution: The compressor will probably have some residual pressure when removing the caps for hose install and will come with oil already installed. The A/C compressor can mount at the upright or 90 degree position. If you mount it at the 90 degree position. The discharge port will allow some oil to be pushed out of the compressor.You may chose to keep both fittings pointing upward when installing the hose to retain the oil in the compressor. One hose runs from the upper left line coming through the firewall(lp gas line) and goes to the inlet of the compressor. One hose gets installed between the compressor discharge and the condenser(hp gas). The ends of the hoses are all o-ring sealed. Ensure that the proper countertorque is applied(use two wrenches and don't overtorque) when putting together any of the A/C fittings in the kit or you will be setting yourself up for problems.
Time to install the heater hoses. I purchased a long piece(I think 10') of 5/8" heater hose from the hardware store. Just make sure you have enough. You'll also need a bunch(at least six) of hose clamps for this heater hose. The hard part of installing the heater hoses was fitting the adapter for the water pump. It was originally 3/4" hose adapter. When I tried to put in a 5/8" hose adapter it was to wide at the nut portion of the adapter to thread in and provide full contact. The nut portion had interference with the water pump body. I ended up purchasing a short section of pipe and a double female connector to move the nut portion out away from the water pump body. Two valves are supplied with the kit. One valve is a manual shutoff valve and one is a cable operated valve. The manual valve gets installed in the hose installed from the upper right pipe coming through the firewall and goes to the water pump adapter we just discussed. You select the location along the hose. The second valve is more tricky when it comes to location of installation. I routed a hose from the bottom right pipe coming through the firewall and it runs to the fitting on the intake manifold by the A/C bracket. When the hose is run then you can move back to the inside. Don't worry we'll get back to that cable operated valve soon.
You can start off by reinstalling the radio. Take care to ensure the defrost/ac hoses don't get torn when putting the radio in. Reinstall the ashtray. The next part is a bit of a pain to get right so be patient. There are two cables supplied with the kit. The longer cable gets attached to the bottom lever and routes through the firewall to the engine compartment. This is the cable that operates the heater control valve. My installation was a A/C cab and I already had a opening where an original cable came through the firewall, so I just routed the new cable right where the old one went through the firewall. If you have a none A/C cab you may have a similar grommet to route the cable through or you'll have to improvise. The cables are held on the pins with some small push nut type fasteners. The ones supplied with the kit just made me angry so I bought a small assortment at the hardware store to prevent further frustration. The important part about all these cables are that they are adjustable by changing the location that the metal clips hook on to the cable. In my case, I had to mess with both cables on the end where it attaches to the control unit to allow full motion of both levers. The short cable gets routed from the middle lever pin to the defrost damper on the upper left hand side of the A/C unit. I would recommend ensuring that the middle and lower levers have full travel after tightening the attaching screws at the A/C control panel. After you verified this you can install the short cable to the defrost damper and then tighten the clamping screw down at the bracket on the left side of the A/C unit when the cable will provide full open and close position of the damper. The bottom lever should be placed in the cold position. You should hear the microswitch click when you are sliding the lever toward the cold position. Now we move back outside. The cable gets installed in the hose we left alone earlier. The key point here is that the cable needs to be routed to prevent to tight a radius on turns. In my picture you'll see I have a loop to provide this. Once routing is determined then you can figure out where to cut that new hose you installed earlier so the cable operated valve can be installed. When the valve has been installed then you'll need to adjust the clamp screw on the cable operated valve to allow full valve travel. Test the full throw of both middle and lower levers to ensure proper operation. Connect the wire harness to the A/C control panel and install the panel in the dash. Recheck for proper operation of the middle and lower levers. Adjust as necessary. The wiring of the system is very straight forward so I'll let you figure it out. Just ensure the green wire going to the compressor is not hooked up until your ready to charge the system. You need to have the manual heater valve and the cable operated valve open when you first start the engine. This provides coolant into the heater section of the evap/heater and prevents freeze-up of the heater coil. Make sure the A/C compressor is mounted tight and the belt tensioned properly. The A/C compressor can mount at the upright or 90 degree position. If you mount it at the 90 degree position, which I did, oil may come out of the hi pressure gage connection when the system is charged, which it did. Hopefully your other belts are new also. Unfortunately, my alternator belt is not new because my new alternator belt wound up on the A/C compressor. Now you can take the truck to an A/C shop or attempt the charge on your own. I don't recommend this unless your willing to spend some cash to buy a R-134A gage set and a vacuum pump which is capable of drawing a deep vacuum(greater than 29.0"). The point of the deep vacuum is to remove moisture from the system. All the lines were open so this should be done. This also allows you to check for leaks in the system. This is a must if you don't want to be charging all the time. Also if you take it to a shop, make sure they evacuate the system and hold it at least 30 mins. The longer the better. The charge is more touchy on the R-134A system. Overcharging should be avoided. Don't forget to shut the manual and cable operated heater valves before charging the A/C system. Place the control panel lower lever in the full cold position and connect the wire at the A/C compressor. Run the fan on Hi Speed with the doors and windows shut. This system runs a relatively low suction pressure so don't be suprised when the suction pressure is running around 20#. The important part is charging to get the air outlet temperature cold and stopping when the system is functioning correctly. Well I think this wraps up the Old Air A/C system installation. Good luck and enjoy the fun.

Don

[ddsmith]

I installed the compressor in the 90 degree position. Meaning the discharge and suction fittings are 90 degrees to the top facing the passenger side fender. I would strongly recommend against this. The unit ran fine in the first season but is now seized up. Just thought I would provide this information to help people learn from my pain.

[krue]

Can you repost the pics for us?

[ddsmith]

To All,
I am sorry to say that the picture were being hosted on a website that no longer exist and the pictures are history. Wish I had saved them but I wouldn't have any room if I saved it all.