AC Install Recap

[Brett Proctor]

Quick update

System is complete,
I ordered one of those recharge kits with everything you need in it. (vac pump, lines, manifold ,etc.)
Quality of the items in the kit are not the greatest but if I pieced together a system with quality items the cost was more than I wanted to pay for something that will only be used a few times.
Had an issue with replacing the drier and expansion valve. I replaced those with new ones but the problem was that Subaru made a change in them during the production run and I got the wrong ones. So I placed another order and this time got the right ones. When I pulled the used parts out of the vehicle (so I had something for the mock up) I wrote down the year and vehicle the part came out of so I know I ordered the right part. They just made a mid year change that I didn't know about.

So just waiting on the recharge kit now.

 

[Brett Proctor]

Got the recharge kit but no freon yet so I decided to do a preliminary vacuum test just to see if I have any leaks.
Got babysitting duties so after they pick her up I'll check to see if the gauge still reads 30.
So far after 1.5 hours its still holding

Not a big fan of the gauges. Very narrow readout range on the vacuum scale.

I guess this is all the pictures you get
Keep getting error message when trying to upload the others.

 

[Brett Proctor]

After over 24 hours the gauge has moved a little
Not sure if its a leak in the system or a leak in the test equipment.

Next step is I'll pressurize the system with air and see if I can find the source (if any) that way.

 

[Brett Proctor]

Pressuzed the system and found a very small leak At the high pressure fitting at the condenser.

Cleaned the area where the leak was at and applied a little more filler rod material to seal everything up.
Pressurized the fitting and it still leaked.
Ground back some of the filler material and cleaned everything before applying a new layer of filler.
Pressurized the fitting again and it still leaked.
Attempted to apply a wider area of filler material to seal up the leak.
Pressurized the fitting and it still leaked.
At this point I had enough screwing around with it.
I removed all the old filler material on the hard line and at the manifold fitting and started all over including using a new filler rod.

Pressurized the fitting and no leaks. Success.

System has a vacuum on it now and I'll check it in 24 hour to see if the gauges have moved any.
All the videos I've seen on this have said wait 30 minutes to see if it holds a vacuum.(30 minutes is not long enough if you have a very small leak like I had) If it holds the vacuum after 30 minutes then your good to go
If I had done this and not wait for 24 hours the system would have been charged and the freon would have slowly leaked out.
I have also added half the required amount of pag oil to the system. Put it in the drier. The other half will go up at the compressor.

 

[Brett Proctor]

I posted the out come to this install in my build posts but not here so to save you the pain of looking for it there I'll let everyone know here that the system is up and running and is working great.

When it gets hotter outside I'll take more readings and post them to let everyone know how the system handles 100 degree temps.

 

[Brett Proctor]

Ran a quick test on the output of the AC system just to see if it still was working.

Before

After. Took about 1 minute to reach this temperature.

I didn't have the gauges hooked up to see what the High and Low pressures are but I plan to do that next time I check the system.

 

[Brett Proctor]

Haven't worked much on the car but yesterday I had to move it out of the garage and before I moved it back in I took these readings'
Before

After

I think I have too much pag oil in the system. When I first started the system up the compressor was reluctant to turn over. It took a couple attempts before the compressor started turning over.

 

[farfegnubbin]

This whole write-up is really helpful to anyone tacking an a/c system in any kit car. Thank you for continuing to update it.

 

[Brett Proctor]

This whole write-up is really helpful to anyone tacking an a/c system in any kit car. Thank you for continuing to update it.

Your welcome.

During my time here I've heard mention that some people did put HVAC in their cars but finding information on it was impossible. What system they used, how it was plumbed in, what controls they used. Did it even work.
No information that was helpful. so instead of putting this in my build and have it get buried and never found I put it here and try to make the information somewhat useful. I didn't do a step by step documentary on it but if anyone has questions I'll try to answer them
I couldn't tell you how many hours I spent in the yards looking for a unit that would fit in our cars with minimum effort. (you get an idea from all my other posts on HVAC) I knew I wasn't going to find the perfect HVAC that would fit with no effort.
When I came across that Mercedes unit (by accident) I couldn't believe my good luck.
Then it was just a matter of getting it to work outside of the car without any control modules or having to use other parts from the donor car.
After getting it to work it was just figuring out where to mount it. Of course if I were to do it over, there would be some things I'd change. But I am happy with the results.
The system works great
I also found out the problem with the compressor. It helps if the belt is tight.

 

[Brett Proctor]

Thought it might be useful to add the wiring diagrams that I used to this.

Mercedes OEM wiring diagram for the unit. (forgot to down load the legend, I'll locate it and download it )

I used the AC wiring diagram from a 1998 Forester since it was very basic and easily adapted to what I needed
OEM 1998 Forester

This is the wiring diagram that I came up with

This is the fan wiring diagram

Thanks Warren
I didn't have to start a new post.

Mercedes OEM Legend

 

[Brett Proctor]

Forgot to post the wiring diagram for the Mercedes ignition switch which is needed for the CAN network to work. Without this the unit wont work.
The key needs to be in the run position
The CAN wires at the ignition switch need to be connected to the CAN wires at the unit and the small gauge red wire needs to be connected to a power source (7.5A) to be able to turn the ignition switch on and the brown wire goes to ground.
There are 2 CAN networks coming out of the ignition switch. You want the brown and brown/red wires