Hi everyone,

Within the past few months, I've been working on getting my 1987 Wagoneer's Air Conditioning up and running. I've been converting it to R134a and whatnot, with a new compressor, condenser, drier, TXV, basically the whole nine yards. Right now, it's kinda on hold because the evaporator is leaking. However, that little quick disconnect thing at the outlet of the filter drier was slightly leaking too. I gutted the little valve, but still couldn't get the stupid thing to seal correctly. So I began looking for replacements...

I came across a new one that looked awfully similar to the old one. It's sold by National Parts Depot and is for a 1967-73 Mustang/Cougar. Lo and behold, the business had a location about 15 miles from me, so I went to check the compatibility of the fittings. To my delight, I believe it will fit and work in our Jeeps. The assembly is two pieces. One side goes the liquid line TXV hose, and the other side screws onto the filter drier's outlet. I've already confirmed that both ends DO fit on the drier and TXV hose. I'll be replacing my Evaporator and Heater core over Thanksgiving break next month, so hopefully, maybe by the end of next month or early December, I'll update the thread on how things go.

Here's a link to the parts. I picked them up in person for around $83.
https://www.npdlink.com/product/fitt...n-steel/209612
https://www.npdlink.com/product/fitt...%3D0%26year%3D

Few quick questions for when I change out my Evaporator.. Regarding the method of replacement, I'm thinking I'll just split the heater box. Nothing wrong with this method? Also, my new Evaporator doesn't have the temperature probe hole for the A/C cycling thermostat. Should I just re-route the probe around the evaporator onto the outlet side of the evaporator (the side of the evaporator that faces the heater core?) or the inlet side (the side that faces the blower motor?)? If I reroute it around the evaporator, should I bend the probe and poke it into the tubes/fins? I just wanna know what works, and what doesn't work. Thanks!

 

Splitting the heater box is the standard method for replacing the evaporator. It's the right way to do it.

For the missing probe hole, route the cycling switch probe to the outlet side of the evaporator (the side facing the heater core). Don't poke it into the fins. Just strap the probe firmly against the metal outlet pipe. This will give you an accurate reading and reliable cycling.

Good luck with the project.

 

Any advice on where and how to split the heater box? I just can’t go though removing the whole dash.

 

Awesome! This is exactly what I needed to know! Thank you very much! It may be a little while, but I'll make sure to update the thread.

 

Of course, I haven't done any of the work yet. I'll be starting on it next month. However, I've done plenty of homework figuring out what I need to do. Here's a good write-up made by a member of the forum. I'll also attach a gentleman's YouTube video that I found very insightful.

https://www.cherokeeforum.com/f2/how...erokee-270977/


If I come across anything interesting during my endeavor next month, I'll make sure I note it. Heck, I might just make my own write-up here; we'll see how it goes.

 

Well, I said I'd give an update to my thread... By far, this was one of the most labor-intensive projects I've conducted on my jeep. Anyways, here's some stuff I ran into....

When I dismounted the dashboard, I found it made things a bit easier to loosen the steering column bolts. Don't take them out all the way, but just loosen them up drastically so that the steering column can come down a teensy bit. Also, be careful prying up the decorative defroster bezel; there are some fragile clips.

I chose to use the UAC EV4177AT evaporator because I felt it resembled the design of the original evaporator better than others, and it also has a "distributor" on its inlet (better refrigerant distribution throughout the coil, maybe better efficiency?). However, I had to modify the UAC evaporator quite a bit to get it to fit inside the HVAC box. I had to grind off some of the metal on the evaporators 'bracket, near the bottom of the coil, on the corners. Fortunately, after some careful cutting, I got it to fit (albeit a big, snug fit vertically with the HVAC box lid). I also had to do some cutting on the plastic HVAC box where the evaporator tubes go in. So be prepared for that..

I re-located the cycling thermostat so that I could have more length in the capillary tube. That way, the end of the capillary tube could reach the evaporator's outlet. I gently clamped the end of the capillary tube to the evaporator's outlet tube with a hose clamp. BE CAREFUL NOT TO CINCH THE CAPILLARY TUBE. I've found that you can test the cycling thermostat by spraying the capillary tube at any length with the 'frost' out of an air-duster can. If you spray it with the frost, you should hear the thermostat click loudly and lose electrical continuity, then, as it warms back up, it will click again and have continuity.

Fast forward a bunch, and I got everything back together and started the Jeep up. I only got airlfow out of the defrost vent... Shoot.. Must've hit a vacuum line somewhere.. Hooked up my smoke machine, and sure enough, a single vacuum line under the dash above the HVAC box became disconnected during reassembly. So I had to dismount the dash AGAIN to reach and fix that vacuum line. I'd highly recommend getting a small handheld vacuum pump from Harbor Freight. That way, you can test your whole HVAC system before and after reassembling the dash. After this mishap, I noticed my speedometer quit working too.. The connector came unplugged from the cluster after having the dashboard dismounted. So keep an eye out for that as well.

After all this fuss, I used my JB 7Cfm vacuum pump and pulled a -30inhg vacuum on the system. It held flawlessly with no rise or loss of vacuum over several hours. This made me very happy. Back in May, I had the A/C 'sort-of' working, but only achieved a -18inhg vacuum. So my leak was indeed in the old evaporator core. I also pressurized the system with 110psi of Nitrogen, it held great for over 72hrs and stabilized around 108-109. Finally, yesterday, I got around to filling the system up with refrigerant. I put in exactly 2 cans of R134a ( I think i have close to 6-7oz of UV dye Pag100), and my low/high pressures looked pretty good, being around 20-30psi and a little over 150psi in close to 80 degree weather. Vent temperatures were in the low 40's. Great!

Today's been a bit hotter than yesterday, maybe mid to upper 80s, so I figured it'd be a good time to test the A/C. At idle in the sun, I'm running low 40's vent temps, and they'll go lower than that when driving. At lower blower fan speeds and when driving, the cycling thermostat will cycle consistently and properly. I'm very happy! We'll have to see how it does when it gets even hotter out.

Most importantly, the quick disconnect on the filter drier works fine. It is indeed compatible with our Jeeps. Later tonight, I'll try to upload some photos I took during this whole ordeal.