My w124 evaporator removal thread

[ps2cho]

I am getting ready to order all my parts I need for the evap replacement on my 1987 260E w124. Car was converted to R134a by dealership some time ago...Date Markings on sticker are all rubbed off.
I will be doing it myself.
Want to keep it all consolidated like my transmission removal thread. Cleaner and easier this way...

First my Reasoning/Diagnosis:
A/C works, but leaks out after about 1-2 weeks. Took it to a local euro indy (worked on 124's before) who checked for leaks and could not find any. He put in some UV dye and when we pulled back the carpet on the passenger footwell and used the UV light there was dye present on the side of the heater box (looked old though he said, probably not his dye). Safe to say it is the evaporator that is the culprit?
Anywhere else I should check before tearing up the dash?


General Evap Removal Questions:
Got 5 questions as of right now...

1) Brand of Evaporator? ACM good?

I want to replace all of the vacuum pods....Sounds a good idea for futureproofing? I only ever want to do this once...

Part number list:
======================================================
124-800-00-75 = Defroster pod (dual chamber)
124-800-02-75 = Center vent pod (single chamber, twist-on)
124-800-03-75 = Diverter pod (single chamber, small, attaches w/3 clips)
124-800-04-75 = Recirculation / fresh air pod 1 (dual chamber)
124-800-11-75 = Recirculation / fresh air pod 2 (dual chamber)

124-800-01-75 = Footwell pod (round, small, to VIN A289309, 1986 to early 1987, two required)
124-800-09-75 = Footwell pod (rectangle, from VIN A289310, late 87 through 95, one required)

2) Any other pods not mentioned there? My '87 260E VIN is A5390xx so I would need the late footwell pod correct? Seems a higher VIN# than 289310...so just want to double check I got this right.

3) Any other items you guys recommend replacing?

4) What about testing procedures? Is it possible to test the system with everything apart to MAKE SURE the leak is resolved before I put it all back together?

5) Does the Blower Motor need to be removed? If so, what about replacing the regulator on it?


Projected costs:
~$500 for Evap and 6 pods.

Reference threads:
W124 (124.290) Evaporator, Vacuum Pod, and Bulb Replacements
W124 climate control vacuum pod replacement
My turn for the Evaporator Party

Your list looks pretty good. Definitely do a podectomy while it's apart.

Are you SURE that the leak is not around the expansion valve? It can sometimes leak into the passenger compartment and fool you.

Now would be the perfect time to reverse convert back to R12. Now that most of the cars that originally used the stuff are off the road, the price has come back to a point not terribly more expensive than R134a.

I think the ACM is what most folks prefer. If I recall correctly, it is not dissimilar metals as is the original.

Examine all around the heater core, especially the connections for any leaks. They are not bad about leaking, but if it is, now is the time to replace it.

Once you have the evaporator in place and connected BEFORE starting the replacement of everything else check for leaks. How you do that is determined by what you have to work with. At the very least, do a gross leak check by pulling a vacuum and seeing that holds that vacuum for at least about 10 or 15 minutes, overnight would be better.

If you have nitrogen, a little R22 and a sniffer, that would be better. Both of those are ways that you can leak check without running the system.

The blower motor does not need to be removed for this operation. Consider this a separate repair.

Do you have a factory service manual or CD? It is invaluable for this project. I prefer to pull the steering wheel which means following the FSM for disarming and storage instructions. There are those who have lowered the steering wheel all the way and managed this job without pulling the steering wheel, but that's not my preferred method.

When changing pods, proceed cautiously. A broken plastic lever or piece connected the pod presents some serious challenges to over come.

Don't get in a Flat Rate hurry on this job. Take your time and lay out subassemblies and associated parts and fasteners in the order that you take them off, then reverse the order when you go back together.

Keep us posted and best of luck,
Larry

[thinktank]

im going to try

[ps2cho]

Thanks Larry,

Yep I have the FSM on the job. Any other 3rd party ones?

My dad actually managed to get hold of 12x12oz cans of R12 so I would love to switch back. I have a sniffer, but I took it to someone else because I just wanted a second confirmation that he couldn't sniff anything in the engine bay either....just to cover any mistakes myself.

Propane OK in place of Nitrogen? That's what I was using before.

The Indy used his sniffer around the expansion valve and said he couldn't get any signs from it. I thought about replacing it first, but if I can't sniff any leaks on it, should be OK?

Are you aware of the correct procedures for a reverse conversion? It will be well worth your while.

As far as the propane goes, I'm a purist. I personally would never introduce a flammable or any other foreign substance into an a/c system for ANY purpose.

It would be illegal to draw a vacuum as a gross leak check and then once it passes that, blow a little R22 in the system for leak checking reasons. The legal way to use R22 for leak checking is to pressurize with Nitrogen and then introduce a few ounces of R22. You can then blow the 22 into the atmosphere legally under those circumstances. The reason 22 is used is because it is highly detectable by a sniffer. Too bad it's illegal to just shoot some R22 in the system without the Nitrogen. The Nitrogen pressurizes everything to help with leak detection, but for your purposes, a pound or so of R22 would probably verify your evaporator as leak free. Too bad it's illegal.

[macdrone]

You know alot of companies use propane instead of R134A anyway right? And that freon itself is a flamable gas also? Shouldnt make any difference but you should replace the dryer and the sensors on the drier since your system will be open to the air. Also be aware A/C compressor would probably love a new charge of oil before getting all charged up.

Neither 12 or 134 are considered flammables. I don't know where that could have come from. You must not be in the US, because to my knowledge Propane is NOT used as an OEM refrigerant in any US systems. I know some farmers that use it in their tractor a/c systems, but they didn't come from John Deere that way.

R/D replacement is part of a proper reverse conversion, or any conversion for that matter. The complete flushing of ALL oil from ALL components so that fresh R12 compatible oil is part of a proper reverse conversion as well.

I have NEVER had trouble reusing sensors that have been "open to the air." You have to transfer them quickly and not leave them around on the bench overnight, but there's no problem reusing them as long as they're in good shape. When I do considerable system work, I pull the old R/D with sensors attached and seal it. Then after everything else is in place I put in the R/D last and not until I'm ready to start the evacuation very soon after it's installation.

[ps2cho]

Thanks for the info for post-op checks. I'll make it work.

Should I replace the RD, but keep the sensors? Anybody explain why either of these would need to be replaced after being exposed? Last thing I'd want is other issues after the leak is resolved.

At least I am learning quick about the A/C system! Never done any work on them before as my wagon has worked since I bought it without any issues. *knocks on wood...*

The R/D should be replaced any time the system is opened for any length of time. If you have really good vacuum pump and a somewhat new R/D, you might get by with not replacing it. In the case of a refrigerant conversion it MUST be replaced because it has accumulated the wrong type oil.

A conversion involves flushing the oil out of ALL components, replacing the R/D and distributing the correct amount of oil throughout the system; couple ounces in the condensor, a couple in the evaporator, etc. After everything is sealed up and while the vacuum pump is running, turn the compressor about a dozen times by hand to make sure there is no liquid locked in the compressor.

I've never heard of replacing sensors as a preventive maintenance step. As soon as you open the system, pull the R/D with sensors attached and seal it in a plastic bag. Then put the sensors on the new R/D just before putting it in place as the last item to seal up. Start your evacuation as soon as the R/D is in place and sealed. This pulls moisture out of the system before it has time to start soaking in the R/D dessicate.

[ps2cho]

I understand. The RD is not an expensive item looks like ~$25 new so I will put that on my list.

I have a vac pump...So all that is needed is to let it run overnight and then turn the compressor by hand and that should be sufficient in regards to "flushing" the system?

Do you know which of the 6 vacuum pods are the ones that are accessible from the glovebox? I am thinking of trying to cut down the costs a little on the items that can be replaced in the future without much work.

[babymog]

There is one pod accesible with the glovebox out, but it wouldn't be easy. I believe that it is the defrost pod.

Also, the footwell pod is accessible with the radio and CCU removed (2 pods on the '86 through early '87).

I'm sorry I thought you knew what was involved in flushing the system. To do this, you break every connection and use a flushing solvent blowing it through each line, the evaporator and the condensor and blow it out THOROUGHLY with compressed air.

This flushing is necessary to remove all the oil that was used with the 134. Once everything is thoroughly flushed and the flushing solvent is THOROUGHLY removed, THEN you have an empty system so that the correct amount of oil can be put in the system.

BTW, flushing of the compressor is NEVER done with solvent. Invert the compressor and turn it by hand to get out as much oil as possible, then put an ounce or two mineral oil or a synthetic R12 compatible oil and turn again by hand to rinse that through. Once all oil is out of all components and lines, and your new evap is in place, connect everything, saving the R/D for last as described earlier.

This is alot of work to go through, I know, but to do this job right, you would even have to do it if you stay with 134, because you have no way of knowing how much oil is in the system.

[Hirnbeiss]

I sure would want to convince myself of the leak location before diving in on an evaporator. Your leak rate is high, so the dye should be plainly visible wherever it is.

It sounds as if he's done about as thorough of a diagnosis as can be done without pulling the dash. It wouldn't hurt to pressurize with nitrogand a few ounces of R22 then check with a sniffer, but it is pretty well diagnosed.

[ps2cho]

Thanks for the info guys. I'll pull back the carpet next week and take some shots of the UV dye I can see on the corner of the heater box.

I would figure either way though it has to be leaking...If the expansion valve is not, where else does the dye come from?

The only thing he mentioned about the running of the A/C was that it was not as cold as it should have been. He said the low side was 50 (psi?) and the high side was 200 (psi?). He mentioned it could be a clogged expansion valve. Seeing as I will be getting a new one anyway that would resolve it, but any thoughts on other possible causes?

There was a very, very minor sign of residue on the compressor...Are there seals that can be replaced or is a new compressor needed?