Air Conditioning Restoration Part II

[Rob Peters]

Well, now that I got the stitches out of my hand I was chomping at the bit to get back, in earnest to my Air Conditioning Restoration. 

In my past post on this I had mentioned I was having trouble getting the POA valve and the Expansion valve off of the Evaporator coil.  Last week I removed the Evaporator Coil from the car.  It was a little hard to do one handed due to my hand surgery but I was able to get it out.  A couple days ago, before the stitches removal I was able to get the Expansion Valve off. 

Tonight, after multiple soakings of PB Blaster on the fittings of the original POA Valve I was finally able to get the original POA valve off.  I know now that I would never have been able to get it off of the Evaporator Coil, with the coil still mounted inside the box, without damaging the lines on the evaporator coil.

It took clamping the evaporator coil fitting to the POA Valve into a vice.  The problem with doing this is it put undue stress on that line with the evaporation coil hanging in the air unsupported si I had to build a support platform to support it.  With the evaporation coil supported and the vice holding the line fitting that goes to the POA Valve and it soaked good in PB Blaster it still would not budge.

My next step was to get my torch out and heat up the POA Valve.  This was suggested by "Old Air Products" where I purchased all of my new parts for my AC system.  With the vice holding the nut on the Evaporator line, and the POA valve heated with a torch for 3 minutes,  I put a pipe wrench on the POA Valve and tried to turn it but unfortunately the base of the vice would not stay locked and the torque on the POA with the pipe wrench was causing the vice to rotate on its base.  I reheated the the POA Valve with the torch again, placed a 15 inch wrench on the vice to hold it into position and a pipe wrench on the POA Valve and most of my 225 pound body weight on the wrenches the POA Valve finally broke free.

rob

[Rob Peters]

Now, with the POA and expansion valves off and the Evaporator coil out of the car it was time to proceed with the flushing of the Evaporator Coil.  If you had followed the earlier posts, when I disassembled my system I found a lot of oil in the lines.  According to what "Old Air Products" has told me when I reinstall my rebuilt compressor I should put about 10 1/2 ounces of oil into the compressor.  

With the amount of oil I found in all of the old lines I was sure there would be oil in the evaporator and the condenser coils.  This was another reason I wanted to remove and inspect my evaporator coil.  I am now very glad I did.  I know at I drained at least 3 ounces of oil out of the evaporator coil.  This coil is the farthest component from the compressor and I feel that much oil in the evaporator was very much excessive and I was glad I removed it.  Once I got as much oil out of it as possible I started flushing the evaporator coil with Denatured Alcohol.as suggested by "Old Air Products".  I used about 1/2 gallon of denatured alcohol to do multiple flushings of the Evaporator coil followed by blowing it out with compressed air.

So now my evaporator coil is flushed and as soon as I straighten out all of the fins in the Evaporator Coil and all of the denatured alcohol has had a chance to evaporator I will reinstall it.

Due to the fact I would have to remove the front bumper, filler plate and numerous other parts,  to try to flush the condenser coil, I was thinking bout trying to flush the condenser coil with it still on the car.  After seeing how messy and hard it was to flush the evaporator coil, I now think I will go ahead and remove the bumper, filler plate and other parts and remove the evaporator coil to do a proper flush of the condenser coil.

After I have done that, I am sure I will find considerable buildup of oil in the condenser coil.  I will save that for a future post once I have the condenser removed.  Once the condenser is flushed I will be able to start reassembly of all of the parts I have removed..  Thanks to everyone who has sent along encouragement, suggestions and assistance. 

Thanks also to Willie for supplying me with a few parts I needed.  

rob

[cny first gen 71]

What no pictures??? You know the deal Rob no pictures it didn't happen

[Rob Peters]

Today I was able to remove the Condenser Coil.  I have flushed it out real well with denatured Alcohol.  Since the Condenser coil is the lowest point in the cycle of the system and the amount of oil found in all the other areas of the system I expected to find a lot of oil it it.  After all, all of the lines and the evaporator coil had a ton of oil in them.  

As it turned out there was very little oil in the condenser coil.  It was a bit of work to get the condenser coil out and at first I was upset that there wasn't much of any oil in it and thought maybe I should have just skipped this step in the restoration of the AC System but I would have always wondered if maybe there had been oil in it.  To remove the condenser coil you have to remove the front bumper, turn signals, bumper to grill filler panel, (the grill was already off), the hood release etc. etc etc.  You will see in the pictures the Monte looks like it is smiling but not sure why it would be smiling with this many pieces off of its body.

Well Steve....here are the pictures you requested.

rob

rob

[imr]

How hard was it getting the evaporator out. I am guessing your going with 134a

[Rob Peters]

Antoine,

When I removed the Evaporator Coil last week I was working with only one hand due to surgery for trigger release on 4 fingers on my left hand so it took me a little longer than it should have.  Also, it took me a little longer because, with the evaporator coil mounted inside the plenum I could not break the fittings on the expansion valve and POA Valve free and if I had left it in the car I would have damaged the lines and would have had to replace the evaporator coil.  

That said......  to remove the evaporator coil it is not real hard if you can get the expansion valve and the POA valve off the evaporator fittings.  Once the two valves are off you should be able to remove the evaporator coil out by completely removing the plenum side on the motor side.  It is held onto the firewall with 2 or 3 speed nuts and one or two bolts.  Also it is held to the other side of the plenum with 6 to 8 bolts.  Once these nuts and bolts are removed the engine side of the plenum should easily come off.  Just a note, there is also a relay and a vacuum canister mounted onto this side of the plenum and must  be removed.

I had heard from another member that once the engine side of the plenum was removed there may be a bracket on the evaporator coil which was holding it to the plenum but my 70 did not this bolt and bracket holding it to the other side of the plenum.  With the engine side of the plenum removed I was not able to get the evaporator coil out because it was catching on the firewall.  The reason for this is where the air would enter the interior through the firewall there is a outward facing lip on the firewall which prevented the evaporator from clearing.  To combat this I only had to remove one speed nut, one bolt and loosen another bolt near the top and side which secures plenum side nearest the fender and this allowed me to remove the evaporator coil..

I hope this is clear.

Time wise, working with one hand, it took me about 1.5 to 2 hours to remove the evaporator coil.

Today, to remove the condenser coil I think it only took about 2 hours.  One of the hardest things to remove to access the condenser coil was the bumper to grill filler panel.  This is the silver panel that fills the area between the bumper and the grill and the bumper and the fender extensions.  If you look at this filler panel above, pictured next to the bumper you will notice the number of holes in this panel.  That's right, there were 11 bolts holding this panel in position.....total over kill for mounting this panel.  I think it weighs all of maybe 5 pounds.

rob

[imr]

very clear. you intend to go back with 134a correct. has anyone notice any coming characteristic that are different better or worse converting r12 to 134a

[Rob Peters]

About 17 years ago, before I really knew about R12 to R134 change I had my system charged with R134.  At the time I was told the conversion was simple and the old only needed to be purged from the air and R134 put in.  I did not know this was not true.  As a matter of fact the AC worked for several hundred miles and then quit blowing cold air.  I tried to add some more R134 freon but it still would no blow cold air.   I think this is how so much oil got into my system.

At the time I did not replace the POA valve, Expansion valve and drier assembly.  I later learned these three items would need to be replaced.  My compressor was slinging oil on the inner fender well and the hood insulation.  I have also had my old compressor rebuilt and will be going on.

rob

[imr]

I am not sure if the ac works on the monte hard to check in the Michigan cold. I do have some r12 available bbn ke and I always liked it better than r134. I have a 1971 compressor which is the same. I might take bbn it apart and rebuild it. would bbn like to flush the system and clean any trash in the evaporator box. 

[willie]

No problem Rob, glad you are getting her done.. And one handed at that!!!

[Rob Peters]

The left hand is still holding me back some but I look at it as good hand therapy to try to work on the Monte.  Today I started the reassembly of the Air Conditioning.  I am writing an article for the Knight Newsletter and will share the restoration in the May/June Newsletter to be posted as soon as I have completed the newsletter.  In the upcoming issue of the newsletter it will not have the completed article because by the time it is completed my AC restoration will not yet be complete.

I spent about 4 hours starting to assemble the new parts and the parts I had to remove to get to the condenser coil.  In the article I will try to point out the differences in the R12 system and the R134 system parts.  Stay tuned for the release of the May/June Newsletter.

rob

[BobW]

Thanks for this write-up Rob. Previous owner converted to 134, it stopped cooling last summer. I've just started with replacing my condenser, POA valve,evaporator, dryer and expansion valve. I have a March Performance mid-mount accessory drive with a Sanden compressor, new hoses made for that.

I removed and replaced the condenser yesterday. There was a lot of oil present when I bled the freon. The rubber insulator mounts were very sloppy allowing the condenser to move around. I noticed some drushing of the lower tubes of the condenser, the passenger side being enough to possibly restrict flow. Pic later. I've not yet drained or blown through the old one.

Flushed the hard line from the evaporator to the dryer, and the line from the dryer to the expansion valve with denatured alcohol.

So it begins.

[jft69z]

Bob, has anyone mentioned using a parallel flow condenser instead of the stock type?

[BobW]

7 hours ago, jft69z said:

Bob, has anyone mentioned using a parallel flow condenser instead of the stock type?

I've seen that, but I'm beyond that now!

[BobW]

Pic below of the old condenser with the dented/ crushed tube. 

In addition to the oil sprayed when the freon was released, there was a fair amount that dripped from both the condenser and the evaporator when they were tipped during the removal process.

Today started with remounting the bumper from yesterday's condenser replacement.

Next was pulling the Sanden compressor to drain the oil and refill with the proper amount according to the Sanden service manual when putting it back in service. They done, on to the evaporator.

Removed the POA valve and the expansion valve, removed the tall valve cover and the bolts from the motor side of the plenum. My motor is an '87 block with the dipstick tube on the passenger side, removed it!

Opened the plenum, loosened the evaporator and pulled/twisted it out.

The inlet side was almost completely plugged with leaves and debris, much more than the pics below show! No wonder it was never really cold.....🤔

I did not take the time to drain the old evaporator or condenser yet.

After cleaning that out everything went back together rather quickly. Tomorrow I'll get it vacc'ed down and charged.

[Leghome]

They cool so much better with hte parrellel flow condensor like ten to 15 drgrees cooler

[BobW]

12 minutes ago, Leghome said:

They cool so much better with hte parrellel flow condensor like ten to 15 drgrees cooler

Too late now............ 🤔🙄

[Rob Peters]

16 minutes ago, BobW said:

Too late now............ 🤔🙄

Bob,

I am not saying the newer "Parallel Flow" don't cool better.  I can tell you that I am running the R134 after installing new hoses, expansion valve, POA and drier but using the original cleaned and flushed evaporator and condenser and with the temperatures in the upper 90's and humidity about as high as it could be without being rain in Carlisle, PA at our Eastern meet this past June, I can tell you that within a couple minutes with the AC turned on I could cut it down a notch from HIGH.

rob

[BobW]

4 minutes ago, Rob Peters said:

Bob,

I am not saying the newer "Parallel Flow" don't cool better.  I can tell you that I am running the R134 after installing new hoses, expansion valve, POA and drier but using the original cleaned and flushed evaporator and condenser and with the temperatures in the upper 90's and humidity about as high as it could be without being rain in Carlisle, PA at our Eastern meet this past June, I can tell you that within a couple minutes with the AC turned on I could cut it down a notch from HIGH.

rob

Thanks Rob, I'm sure it will be significantly better than it was, especially after seeing the airflow blockage on the old evaporator.

Vac & charge appointment on Thursday, I'll report back then.

[Rob Peters]

17 hours ago, BobW said:

Thanks Rob, I'm sure it will be significantly better than it was, especially after seeing the airflow blockage on the old evaporator.

Vac & charge appointment on Thursday, I'll report back then.

I agree, the debris blocking the old evaporator would have definitely affected the cooling had it not been cleaned out.  I know you are in Florida and having lived there, growing up, until 1968 I know it gets hot and it may get worked a bit more than than some other places but high 90's in Carlisle, PA along with the high humidity we had at our meet there in June, upper 90's is upper 90's no matter where you are.  I think you will be fine.  

If mine had been a daily driver I may have gone with a new condenser and evaporator but being a classic and not a daily driver I think you are going to be cool as a cucumber.

rob

[Jeffrey Aldrich]

Does anyone have pictures of where the two small 1/4 inch lines that come thru the fire wall hook up?

[Chevy Dave]

One should go to the hot water valve in the heatwr hose.  The other one should go to the vacuum reserve canister next to the evaporator housing.

[Joselk1]

I just replaced my condenser last week. No one had them in stock.  I tried to find A parallel flow condenser, and I couldn’t even find a part number for that. The only place that had the condenser was National Parts depot for Chevelle so that’s what I used. Air is working again.  

[BobW]

So...it's been a minute!

While recharging we kept having the compressor seeming coming on and off, belt squealing with each restart, acting as if it was a fluctuating high pressure situation! 

Note this is a friend with gauges, not a shop. We tried different amounts of freon charge with no change. Google search indicated it might the expansion valve might be to blame, though it was new, I replaced it. No change.... 🤨

Yesterday I took the MC to a shop. Turned out the Sanden compressor clutch was at fault. They reshimmed the air gap in the clutch and all is well, and cool! 😁 🥶

[Rob Peters]

Glad they figured it out.  Was going to say just in time for the cooler Temps that are hitting us but with you in Florida there is plenty of warmth, heat left to enjoy the AC.

rob