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Discussion Starter · #1 ·
As some of you noticed lately...I've asked a couple questions regarding air conditioning. This isn't a new avenue to me as I've tried unsuccessfully a few times in the past to get the 79 to blow cold air but have never been successfull.
I attribute this to:
1. not understanding how the system works
2. unsure how to get peak performance from the a/c system
3. not ready to spend the money required to get it functional
4. trusting others to "charge" the system
However...these reasons are no longer valid so in this thread I will document the upgrade/overhaul of my 79's Rabbit A/C system.
First off, my 79 HAD a 1.6L with a York compressor that never really produced good A/C. That motor popped a headgasket so I swapped in a 16V that had a Sanden 508 compressor. I "thought" that with the newer style compressor the a/c would be good to go with a good vacuum and refill. Unfortunately...this was not true.
This is probably because:
1. I didn't do it myself
2. the condenser still sucks
3. the system is 20+ years old.
So I decided to revamp the system. Here's the list of parts I've ordered/had made/am installing.
1. 87 Scirocco condenser
2. New drier
3. New compressor
4. New expansion valve
5. Custom High side line from the condenser to the drier.
6. High/Low pressure Cutoff Switch to prevent system destruction.
I also ordered a vacuum pump and DIY starter kit by Mastercool from ackits.com(HIGHLY recommend).
Let the project begin.
Yesterday I pulled the old condenser out and installed the Rocco unit. The reason is pretty simple...it's larger. It's about 3 inches wider and 1/2 taller.

Before I installed it thought I flushed it with some system flush which I will use in all the lines plus the evaparator. Do not use it in the compressor, expansion valve or drier/accumulator.

I had to squeeze the condenser in but it fit. I also had to drill two holes so the bottom of the rad support. This is because it has two plugs that protrude from the bottom much like 81-84 radiators. Then I used two brackets and bolted it to the upper radiator support.

You can see the two bolts easily on top. One is in front of the hood prop mount and the other is across the way.
On a side note...I always use mk2 fans on a mk1 fan support. The reason is it has more blades to move more air. Plus I just put the wires to the outside terminals so when the fan kicks on it kicks on high

Now the solid metal line that went from the early condenser to the drier won't fit because it's to short. Besides that...I ruined it when I pulled it apart
The Rocco line falls a little short too. I tried to heat it up and rebend it but it didn't really work out. I needed a couple more inches anyway so I just went to the local hose shop and they custom made me a line to the tune of $39 bucks.

Today I turned my attention inside the cab to dig into the evap/expansion valve. I pulled the high side and low side lines into the cabin and removed the knee bar:

Once the plastic tube was removed I had access to the expansion valve.

The black gunk looks nasty but it's easily removed:

At this point be extremely carefull removing the valve because the small line that goes from the evap to the hvac controls is a small capillary that can be easily broken and that would suxor. here's the first part of the valve coming off and also notice the little spring clip removed that held the coiled wire to the evap tube is removed:

And lastly...it's removed. You can see the small capillary line that goes up to the temperature selection. There is a small charge in this line so you know you busted it if you hear it hissing! I know because I've busted one in the past removed some ac/heat controls on a early rabbit:

And that is where I called it quits. While I'm waiting on the parts I will flush the evap and all the lines. There's no way to get the system clinically clean but the cleaner the better.
More to follow.
Thanks for reading,
Jason


Modified by vdubspeed at 5:40 AM 4-22-2008
 

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Re: 79 16V Air Conditioning overhaul project. (vdubspeed)

Here is a tip on hoses:
Check out your local AC supply company. The will sell you hose ends for
about five bucks each and you can buy bulk hose to match by the foot.
Temporarily install the fittings, trim and fit the hose, mark the hose and
fitting to account for any twist or off center trim. Take the hose and fittings
back to the AC supply shop and they will crimp the ends on to the hose for a
few bucks each. Presto, new custom hose for cheap
 

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Discussion Starter · #5 ·
Re: 79 16V Air Conditioning overhaul project. (Cubster)

Quote, originally posted by Cubster »
Was this car fitted with factory air or aftermarket? I'm installing a/c to my car also but it has the aftermarket "CCCCCooool" system in the "cockpit".

Yes...it's factory air. It really wouldn't be hard to retrofit something though. The only thing I would like to do is add a more efficient condenser(parrallel flow vs my old tube/fin) but everything else should be good to go.
Tonight I cleaned the evap out. It had a little gunk in it but the expansion valve was really clogged up with junk.
Anyway...all the goodies are due in Friday. Hopefully by the end of the weekend I'll have some nice A/C.
 

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Discussion Starter · #7 ·
Re: (GEE-BEE)

got the compressor in today and went ahead and removed the old one. I normally daily drive the 79 but currently I'm pimping the moped.
Here's the old and busted beside the new hotness:

Anyway...the rest of the goodness will be here tomorrow. Saturday is going to me an MVAC party for the 79 http://****************.com/smile/emthup.gif
 

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Discussion Starter · #8 ·
Re: (vdubspeed)

got the rest of the toys in tonight. I've been doing some reading in the Mastercool book and I can't believe how wrong I/others have charged the system.
It's amazing it worked even a little. Anyway tomorrow I will attack the a/c system and hopefully get it to work in a correct manner.

I figure if I can tune a 16vT on standalone...I can read a few gauges and figure out what the system wants.
We shall see...
 

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Discussion Starter · #10 ·
Re: (Fein1)

Quote, originally posted by Fein1 »
Added to watched list...It about time someone put in ac instead of ripping it out.

Yes gone are the days that I cared to lose 50lbs in the car to make it a fraction faster.
I guess I'm getting older but screw it...atleast I'm still daily driving a mk1
 

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Re: (vdubspeed)

Oddball tip:
I bought a gauge set from Harbor Freight Tools. It is the typical
Chinese type sold under a dozen or so names. Something like $50.00 or
so. Did a complete conversion including new condenser on an old Chevy
truck and only planned to use it a few times just to get things running.
First time I used it all was well -- it was abut 80 deg or so outside and
the pressures were just a tad on the high side according to the charts. A
bit later I decided to check the charge at higher temps and maybe lower
the charge a bit if it was still on the high side to avoid too much stress
on the old (somewhat noisy) compressor. It was a 112 deg day.
Got everything connected and found the pressures OK but then POW!!!!
The hose on the gauge set burst. Luckily the gauge was off to the side
so my face was far enough away so there were no injuries. Got the valve
closed in a few seconds without any further problems. The hose had
signs of a couple bulges -- this after only using it twice for a few
minutes. Very defective.
Good idea to tie the hoses off to the side and make sure there is as
much distance as possible. And check to see if there are any signs of
bulges, cracks, etc.
 

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Re: 79 16V Air Conditioning overhaul project. (vdubspeed)

Well well well! I'm pretty excited that someone's into making the A/C WORK in their car. Awesome!! I don't normally frequent the MKI forum, but on our local forum my friend PM'd me about this thread because I'm a refrigeration mechanic. High level nerdery.
A few things:
-Don't put any dyes or UV detectors into the refrigerant circuit. It's not necessary and can cause problems.
-For cheap money, get a bottle of Nitrogen to leak check and dry out the system for a more efficient vacuum before charging.
-Make sure the TXV you have matches the refrigerant you're going to use.
-Make sure the oil matches the refrigerant and compressor too.
-I'm really glad you have an actual vacuum pump and not one of those air pressure things. They are useless.
It seems like you have everything you're going to need to get it going. Good luck!
I'll be watching this thread too and see how it turns out!! http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif
 

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Discussion Starter · #13 ·
Re: 79 16V Air Conditioning overhaul project. (hardwareboy)

Quote, originally posted by hardwareboy »
-Don't put any dyes or UV detectors into the refrigerant circuit. It's not necessary and can cause problems.

To late
I put the uv dye in the oil today but not much. Probably .25oz.
Quote, originally posted by hardwareboy »
-Make sure the TXV you have matches the refrigerant you're going to use.

Yeah I have no idea how to tell the difference. I just ordered my stuff from ackits.org and told them I was going to use 134 so they sent me the correct compressor oil. I "ASSUME" they sent me the right TXV???
Quote, originally posted by hardwareboy »

I'll be watching this thread too and see how it turns out!! http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif

Well I got everything bolted back in just now and it's holding a vacuum. I'm about to start the deep vacuum http://****************.com/smile/emthup.gif
 

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Re: (vdubspeed)

Quote, originally posted by vdubspeed »

Yes gone are the days that I cared to lose 50lbs in the car to make it a fraction faster.
I guess I'm getting older but screw it...atleast I'm still daily driving a mk1





WORD to you J
 

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Discussion Starter · #15 ·
Re: (8382)

this project is on hold as of right now.
High side line + alternator = big mess.

Much to clean up and rebuy

Will resume next weekend.
Jason
 

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Discussion Starter · #16 ·
Re: (vdubspeed)

Here we go again...
last weekend I had got it all assembled and the vent temps were about 55 or so. Not great but I was going to try a few more things. Well after buying more freon at Autozone the high side line touched the alternator and EVERYTHING spewed out.
Here's the line.

That was Saturday. I put it back together with the old compressor and crap and drove it around for the next week.
During the week I ordered a new dryer, some more oil for the system and a new parallel flow condenser.
I took the busted line to the local shop and using thier sweet skills they salvaged the ends of my hose, brazed on some new fittings that allowed them to clamp on a newer style hose. Now the ends are reuseable.
So last night I mocked up the condenser and today I went ahead and installed the rest:


The end result: 38-40 vent temps with the compressor cycling on and off! That was with 72 ambient temp tonight so the real test will come when it gets hot out but these temps are at idle and only the rad fan pulling air across the condenser.
Tomorrow I will take it out in the heat of the day and see how it does. The vinyl seats don't help much and neither do crystal clear windows. I thought about tinting the windows but I don't think that will happen.
Thanks for viewing.
Jason
 

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Re: (vdubspeed)

If anybody wants to try a universal parallel flow condenser here is info on
how it was done on a Jag: Should be easier on a Wabbit.
http://bernardembden.com/xjs/pcond/index.htm
And
http://www.ecs.fullerton.edu/~...d.htm

These condensers can be bought on line. Here is a source at random:
http://www.polarbearinc.com/PB....html
I bought the 12" tall by 24" wide with both top and side mounting
flanges. The 24" is actually 25 and 7/98 or so. it looks like the top
mounting channel will have to be notched a bit to clear the hood latch
mechanism.

Have yet to install it so I don't know how well it works.


Modified by R_Pogo at 12:45 PM 5-3-2008
 

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Discussion Starter · #19 ·
Re: (Digital K.)

I think I got a leak because this morning the compressor was cycling good but it slowly vent away and so did my vent temps! I think I need ANOTHER new dryer too because the one that came in shipping yesterday didn't have a vacuum on it so I'm pretty sure I have to much moisture in the system.
But it's getting there.
I swear I will get this thing to blow cold all the time. http://****************.com/smile/emthup.gif
 

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Re: (vdubspeed)

O-rings: too tight and they leak -- too loose and they leak. First make
sure there aren't any burrs or rough spots on the fittings left over from
previous "fixes". Also check that they are still round not oblong. Use a
little AC oil to lube the o-ring before assembly.
Then: here is a trick to get the torque right with o-ring fittings where you
can't get a torque wrench to fit:.
Put the handle of the torque wrench into a vise. Find a wrench about
the same length of the one you are going to use on the fitting that also
will fit the torque wrench end. Grab the wrench in about the same
position as you will have to do when tightening the fitting. Turn the
wrench and watch the torque reading for when you get it right. It might
take less force than you figured.
Practice with the wrench to get the right "feel" for when the reach max
torque for the fitting. Try it a few times with your eyes closed. After a few
minutes of practice you will come real close just by feel. Then tighten the
fitting. Presto, no more leaking o-rings.
On early cars the factory often specified "FF" in their service manuals
and assembly drawings. It was "Fitter's Feel" -- old timers of the day
were trained this way -- no robots.
 
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