1st Gen Air Conditioning Woes

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1st Gen Air Conditioning Woes

Postby furiousbob » Tue Mar 07, 2017 6:14 pm

So I've just picked up a 1990 Trooper and.. the a/c doesn't work. I asked the shop that I work at to help me out and they said no. I even offered money or lunch for a week. "Nope, not touching it". I asked a master tech at a shop I pick up will-call orders from and he said "nope".

Air conditioning is not my specialty. Outside of recharging a h134a system, I've never done anything else. However, I'm starting to think maybe I need to wet my a/c feet a bit more.

As of right now, the compressor does not kick on when I switch it to a/c. I've picked up a pack of r12a as well as a gauge. I was initially going to just try recharging it but since the compressor doesn't even click on, I'm going to need to do some sort of repairing first. I've tried googling and youtubing r12 diagnostics but there isn't a lot of info out there.

Can someone point me in the right direction?
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Re: 1st Gen Air Conditioning Woes

Postby furiousbob » Tue Mar 07, 2017 6:21 pm

http://www.aa1car.com/library/ac98.htm

Here's a quick a/c diagnostics guide. I feel kinda silly for answering my own question and I swear I'm not just trying to up my post count!

But this link might be useful for anybody else that might want to diagnose their own system.
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Re: 1st Gen Air Conditioning Woes

Postby Hack » Tue Mar 07, 2017 7:00 pm

R12 is so expensive, I can see why no one wants to touch it. First thing I would do is use a vacuum pump to see if the system has leaks. You don't want to pump in a couple of pounds of R12, only to have it leak right out. Then you might try to bypass the pressure switch to see if the compressor will even kick in. Again you don't want to pressurize the system, only to find the compressor is shot. The bypass won't tell if you the compressor is functional, but it will at least show whether or not the clutch kicks in. Moreover, if the system wasn't pressurized for a number of years, the seals and receiver/dryer should probably be replaced. Even if you do all of this, you can still pressurize the system only to have something pop (the system is over 25 years old) and all the R12 leak out. You see why no one wants to touch it? Facing this, most would just live without AC.
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Daily Driver: 1995 Trooper Limited, Auto, 3.2L DOHC, Rear LSD, HD Torsion Bars, Moog Cc812s, Cooper Discoverer A/T3 245/70-16
Trail Truck: 2001 Amigo, Auto, 3.2L, Rear LSD, Front Aussie Locker, DOR Drop Dif, HD Torsion Bars, OME 912s, BFG M/T KA2 33x10.5R15
RIP: 1988 Troop 2.6L 5spd. Burnt valve(s). Damaged frame. Parted out. Sent to crusher.
RIP: 1998 4WD Rodeo, Auto, 3.2L -- Ruined by Daughter #1 with Russian assistance. Parted out. Sent to crusher.
RIP: 1989 Troop 2.6L 5spd --- Stripped of all good parts. Body and rotted frame sent to the crusher.
RIP: 1999 2WD Amigo, Auto, 3.2L -- Engine blown and body damaged by Daughter #2. Parted out. Sent to crusher.

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Re: 1st Gen Air Conditioning Woes

Postby RickP » Tue Mar 07, 2017 8:18 pm

First you need to get some gauges and see if you have any pressure in the system. I found a good vacuum pump on Craigslist. I had to replace my compressor and really want to use R12 since it cools better in these old systems. However, I didn't want to waste it, so I used computer duster aka canned air aka R152a. Search R152a on Youtube. I have a leak I haven't located yet, though.
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Re: 1st Gen Air Conditioning Woes

Postby hessmess » Wed Mar 08, 2017 11:57 am

I worked on and off on mine last year, finally got it working. I agree with the above, do a vacuum test first. The pressure switch can be bypassed easily to see if the clutch is working. I also replaced all of the seals I had access to. I replaced compressor, dryer, and the switch inside the box underneath the dash. Nothing worked. We finally figured out I had a plugged line. We ended up pulling the lines and using some air pressure to finally dislodge the plug. Pulled another vacuum and everything worked great.
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Re: 1st Gen Air Conditioning Woes

Postby Ed Mc. » Wed Mar 08, 2017 7:59 pm

Interesting comparison test of R-12, R-134a and R-152a:

http://www.autoacsystems.com/fasttrack/r152tests.html
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Re: 1st Gen Air Conditioning Woes

Postby RickP » Wed Mar 08, 2017 8:36 pm

Ed Mc. wrote:Interesting comparison test of R-12, R-134a and R-152a:

http://www.autoacsystems.com/fasttrack/r152tests.html


With R134, my Trooper was in the upper 40's. With the R152 I saw 38 degrees a few times, but the average was about 40. I just have to find the darn leak.
http://www.planetisuzoo.com/viewtopic.p ... 50#p777041
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Re: 1st Gen Air Conditioning Woes

Postby furiousbob » Tue Mar 21, 2017 2:11 pm

Ok so I ordered new seals, a new expansion valve and a new drier (dryer?). I did some poking around and noticed a whole buncha dried up gunk behind the compressor. I know the compressor/clutch works because I shorted the low-pressure switch and the system kicked on. I unscrewed the block where the high/low hardlines enter the rear of the compressor and checked the seals. They didn't look oiled up but didn't look cracked either.

Now I think that's the culprit for my zero pressure issue.

How likely is it that the compressor would be leaking refrigerant on a 123k mi trooper?

Should I replace the compressor altogether or wet the seals and try dumping in some refrigerant? I'm not sure if the seal kit I ordered has the seals I need for that block, either.

Also, what kind of oil do I use for the seals?

Thanks in advance!
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Re: 1st Gen Air Conditioning Woes

Postby RickP » Tue Mar 21, 2017 2:15 pm

furiousbob wrote:
How likely is it that the compressor would be leaking refrigerant on a 123k mi trooper?


It's more of an age thing than a mileage thing.
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Re: 1st Gen Air Conditioning Woes

Postby furiousbob » Tue Mar 21, 2017 3:43 pm

WELL after doing some quick reading, I've decided to just replace the suction and discharge gaskets on that manifold on the rear of the compressor. I've ordered a/c mineral oil to coat the gaskets/o-rings before replacing them.

The confusing part is: all new/reman compressors from rock-auto use PAG 150 oil. PAG oil is only used for hfc134 systems. SO if I were to replace the compressor... would that mean I'd be forced to swap to hfc134?

Right now, I have several cans of r12a ready to go, including a dye can and an oil charge can. I'm going to replace the aforementioned gaskets and try to charge the system, see what happens.
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Re: 1st Gen Air Conditioning Woes

Postby Dingbat » Wed Mar 22, 2017 7:21 pm

If the R12a you have is like the RedTek R12a, looks like the PAG oil will work.
http://www.redtek.com/win_12a_oilselect.html
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Re: 1st Gen Air Conditioning Woes

Postby furiousbob » Wed Mar 22, 2017 7:31 pm

Oh yeah that's the kit I have. I have the 3 bottles from the kit (2 refrigerant/1 leakstop), 1 can of dye and 1 can of oilcharge.

I've actually already jumped the gun and picked up some Mineral oil from ACDelco. I'm going to get to work this weekend on replacing all the o-rings (except for maybe the ones by the evaporator, I'm not even sure how I'm going to get the new expansion valve in) and if all goes well, I'll hook it up to the vacuum at work and see if it holds. I know I'm supposed to flush the system out since I have no idea how long the systems' been at 0psi and air means moisture... but I'm just gunna wing it. I've spent enough time beating my head against the wall with this thing.
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Re: 1st Gen Air Conditioning Woes

Postby Ed Mc. » Wed Mar 22, 2017 7:50 pm

The compressor does have a mechanical seal and it's replaceable. Not sure what kind of special puller you need to remove the clutch, but I'd expect Autozone would have it as a rental.

The OE seal is $25.52 at this Isuzu parts site:

https://www.isuzupartscenter.com/parts/ ... eid=216496

Jerry Lemond could likely get the seal for you, too.
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Re: 1st Gen Air Conditioning Woes

Postby furiousbob » Sat Mar 25, 2017 11:10 pm

OK so problem located.

I replaced all the o-rings and pre-coated them with mineral oil. I replaced the valve cores on the hi and low pressure valves (mine were leaky). Replaced the drier. I added R134 adapters to the valves. I dumped in a 2oz can of leakstop r12a and I hear hissing. I sprayed some simple green on the compressor and sure enough, bubbles all along the outer housing of the compressor.

I searched for a new compressor on RockAuto and found that they all use PAG 150 oil (they come pre-filled with it).

Can I continue to use PAG 150 + R134 even though I've coated all the new o-rings with mineral oil?

I've heard that mixing PAG and mineral oil can create sludge.
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Re: 1st Gen Air Conditioning Woes

Postby Ed Mc. » Sat Mar 25, 2017 11:47 pm

Looks like you're OK, based on the info from this site:

http://www.aircondition.com/tech/questi ... O-rings%3F

What Oil to use on O-rings?

When replacing A/C system O-rings, it's always recommended to lubricate all O-rings with clean 525 viscosity mineral oil. Oil on the O-ring surface helps protect the O-ring during the assembly of fittings. The use of PAG and Ester oils are not recommended for this purpose. Many PAG and Ester oils attract moisture, which is said to promote corrosion at the fitting.

Sealing washers which are common on General Motors vehicles were designed to be installed dry. Sealing washers do not require any lubricant during assembly. Lubricant will not affect the seal, but the chance of dirt sticking to sealing surface during assembly is why lubrication is discouraged.

Nylog works very well as automotive air conditioning assembly lubricant. One bottle of Nylog can be used to lubricate many hundreds of O-rings. In addition to its' ease of use, Nylog is manufactured from refrigerant grade lubricant, so there is no chance that the product will cause any contamination. Nylog can be purchased at ACSource.Com

We also found the lubricant Krytox to work very well on air conditioning O-rings. Fittings that were lubricated with Krytox were found to still have traces of the product after many months of use. This would suggest to us that the sealing qualities of the lubricant remain intact, even in the high temperature and pressure associated with the automotive air conditioning system.
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Re: 1st Gen Air Conditioning Woes

Postby furiousbob » Sun Mar 26, 2017 12:27 am

Yayy! Thanks!
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Re: 1st Gen Air Conditioning Woes

Postby furiousbob » Sun Apr 02, 2017 3:30 pm

So I got my new compressor from RockAuto and picked up some PAG 150. Couldn't figure out where to put the oil so I dumped 2 oz (to the existing 3 oz that came installed with the compressor) in to the suction port to make 5 oz. I spun the clutch about a dozen times by hand and went to installin!

Install was kind of a pain in the butt because of the bottom 2 bolts. I removed the top 2 bolts easily but figured out that it was easier to remove the bottom bracket by removing the 3 bolts that attach the bracket to the compressor. Got that out, messed around with the different manifold gaskets and slapped everything back together.

Pulled a vacuum for 3 PBR hours (roughly 1.5 sober hours):

Image

The refrigerant that I used (R12a) stated that I needed roughly 16 oz to equal 32 oz of R12. I dumped in about 15oz of the R12a and called it a night.

In the morning, I drove the truck around the block and within 3 minutes:

Image

Thank you everyone for the help! This is my first time actually tackling A/C. All my other A/C-less cars of my younger days just went on without A/C. BUT I'm an a-dult now and I gotta have my A/C. Plus the recent years' heatwaves in SoCal have done nothing to help.
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Re: 1st Gen Air Conditioning Woes

Postby Hack » Sun Apr 02, 2017 3:35 pm

Good luck. Hope the system holds up for you. Stay cool.
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Daily Driver: 1995 Trooper Limited, Auto, 3.2L DOHC, Rear LSD, HD Torsion Bars, Moog Cc812s, Cooper Discoverer A/T3 245/70-16
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RIP: 1998 4WD Rodeo, Auto, 3.2L -- Ruined by Daughter #1 with Russian assistance. Parted out. Sent to crusher.
RIP: 1989 Troop 2.6L 5spd --- Stripped of all good parts. Body and rotted frame sent to the crusher.
RIP: 1999 2WD Amigo, Auto, 3.2L -- Engine blown and body damaged by Daughter #2. Parted out. Sent to crusher.
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Re: 1st Gen Air Conditioning Woes

Postby hessmess » Sun Apr 02, 2017 10:46 pm

Wow that turned out well, and yeah that compressor sucks to install.
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Re: 1st Gen Air Conditioning Woes

Postby Skeletor » Tue Apr 11, 2017 10:23 am

RickP wrote:
furiousbob wrote:
How likely is it that the compressor would be leaking refrigerant on a 123k mi trooper?


It's more of an age thing than a mileage thing.



exactly....as the remaining vehicles age, you'll see more and more glitches popping up...when our Troopers first rode off the
assembly lines, no one would have guess 20,25 plus years later, they are still running..
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Re: 1st Gen Air Conditioning Woes

Postby Ed Mc. » Tue Apr 11, 2017 1:05 pm

It'd be more common to see a leaking compressor seal rather than a split body, but things happen!
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