Hello all,

I'm replacing my A/C evaporator and have the dash out, ready to open up the climate unit and put in the new evap.

I have the spring lock tools (the plastic ones) and they seem to compress the springs ok but so far I can't pull the lines apart. I can't seem to get the needed leverage. Anyone have an idea on this? Would it make sense to dismount and pull back the climate box some to help the lines separate?

Also is it hard to get the lines (with new seals) pushed into the new evaporator? Do you sometimes have to bend the evap lines to make the angles right?

Thanks much!

1. Make sure you have the spring lock tool fully inserted.
2. Keep pulling on the lines, but first make sure you remove the 6mm allen bolt holding the lines and the receiver/drier bracket, near the headlight (NOT the one securing the two lineset flanges together!) It's the one closest to the drier bottle.
3. I would pull on the lines in the engine area, don't mess with the plenum yet, it does take some effort, those O-rings hold it pretty tight.
4. Be positive that you have the tool properly inserted! You are actually EXPANDING the spring to allow the flared end of the evaporator pipe to slide past the spring, you are not compressing the spring.

If you purchased an aftermarket evaporator, the lines probably are not bent correctly. Once you have the new evap installed, it will be VERY difficult to line up the lineset in the engine compartment because they are very rigid. The alignment of the evap pipes must be VERY close, it is a tight fit and any misalignment will make it extremely difficult to install the O-rings/line set. I would recommend making a "gauge" to bend the lines of the new evaporator to match those on the removed unit. You could use a cardboard box, cut to the proper size, holding two edges of the box to two adjacent outside edges of the old evaporator. If you cut the depth correctly, you could mark the location of the pipes by punching a hole where they intersect with the box. But this is just where the ends of the pipe end up in relationship with the exterior of the evaporator, you also need to try to get the angle correct. Don't be afraid to bend the pipes of the new evaporator, just ensure you do not crimp, crush or distort the flared end where the O-rings seat. If you have a black plastic clip on one of the pipes of the old one it acts as a bracket to secure the pipe to the body of evaporator. I would pry it off the old one and cut off the tabs that get shoved in between the fins - you don't need them. Install it on the new one. This will help hold the pipe steady because you will need to push pretty hard when you try to secure the spring lock connection again. You will be very sorry if you do not take the time to get the pipes aligned as close as possible to the original unit PRIOR to installing it in the climate plenum. Minor misalignment can be corrected by bending the steel lines within the engine compartment but be aware this is easier said than done. Always use new O-rings, I lubed them up with a light coating of silicone grease.

When pushing the evaporator lines thru the firewall, be careful. You need to balance using enough force to push the lines thru the rubber grommet (lube it up), and push the heater core lines thru the firewall (aligning both at the same time!) and not bend or damage the flared ends. If you do damage the flared end, it will be difficult to get the spring lock to lock again. But you can't be a wuss about it either, it takes some force to do it. It might help to have a helper look from the firewall side to see how your alignment is before you push the plenum hard.

Always replace the receiver drier, my hose was seized to the bottle but was able to get it off when I removed the hose at the compressor and whacked the wrench with a 5lb hammer a few times.

Pull a vacuum on it when your done, ensure you have no leaks.

Many thanks for your thorough reply!

Since I wrote I was able to get the original lines free by doing exactly as you said. I kept a fairly strong steady pull on the steel lines and after a couple of minutes each gave way.

It is an aftermarket unit I bought, although other than the angles which are about 5-10 degrees off I can't tell any difference whatever between them. The supplier was AC Delco and I bought it with the accumulator (receiver/dryer) too. The new evap includes the black plastic support clip on it. We will use your idea of making a gauge or template to get the alignment correct. A local mechanic I know says incorrect angles are a fairly common problem on replacement evaporators. Do you suppose the exact angle varies among individual cars (even of the same model)?

In a book I read it said to use refrigerant oil to lube the new o-rings. Another possibility is laboratory-grade vacuum grease (which I believe is silicone). If you have any further comments on this or other issues I'd welcome them.

I read PAG oil is hygroscopic and will absorb moisture and not to coat o-rings with it. It said to use mineral oil or silicone grease.

"Also keep in mind when replacing leaky o-rings on all A/C systems, including R-134a systems, that replacement o-rings and their fittings should be lubricated with either mineral oil or an application-specific, silicone-based lubricant instead of PAG or POE oils. PAG or POE oils should not be used due to their hygroscopic nature that can promote moisture attraction, possibly causing o-ring deterioration or thread fitting seizure."
http://www.asashop.org/autoinc/march2003/mech.cfm

On a car with factory original evaps I doubt they vary much, the steel lines in the engine compartment are bent consistently to probably aid in speed of assembly. They can easily control the angle of the lines with whatever vendor they are using.

I'm sure you are already aware, don't leave the new drier open too long, it absorbs moisture quickly.

I bent the evap lines just as you said. The front edge of a desk along with a try square and ruler made a good reference. At my employment place is a superb journeyman machinist who made me a mandrel for bending each tube without disturbing the expanded part or the flare. This was a straight piece about 45 cm long so just a steady modest force was really needed (and the long extension made it easy to see what angle was achieved).

Thanks for the web reference - I think we should conclude a silicone product is the thing to use with sealing rings, because mineral oil is not compatible with R134A, only with R-12 (see www.sanden.com where there is an article on retrofitting R-12 systems to R134a).

Regarding reinstalling the climate unit, I understand the heater core can be removed and replaced with the climate unit in place (no need to remove the dash, just several kick panels and probably both knee bolsters). If that's so then it might be easier to install the climate unit without the heater core and cover (or at least without the 2 hot water lines) then fit them in. This would save aligning 2 items at once. Have you got any opinion on this idea?

Again, many thanks for your comments.

I guess you could remove the heater core/lines. I was able to get it back in position with it in place, though. It might help to remove it, I just got tired of tearing everything apart. I still have not been able to get a vacuum drawn on my repair, so I don't know if I have any leaks yet. Everything is sealed though. FYI, you can use standard #114 O-rings on the heater core, you need 4 total, NAPA had them in an O-ring kit. They are NOT metric.

Cool. It looks like we are good to go on this end. I actually got the evap from a NAPA distributor - people there were very helpful.

I located a place which rents a vacuum pump and gauge set by the day. I am in Illinois where this is legal I guess. The only issue I've heard and read about is that sometimes when you can't draw a good vacuum it is the gauge set, hoses or pump which aren't up to snuff - not always to conclude the system is leaking. This might apply to a rental set in case it did not get good care in the past.

I just had a buddy draw a vacuum on mine after my repair and it is leaking. Vacuum rose 10 in HG from 30 to 20 in 10 minutes or so. Perhaps it could be his lineset/vacuum pump because there was no way to isolate it from the system (no shutoff valves). I ordered an O-ring replacement kit and will try again because I did not replace o-rings in 2 joints I separated (the flanged connection near the headlight and the compressor/hose connection. Hopefully this is where my leak is located.

You should be able to draw a good vacuum with your rental set but whether or not your connections can hold it over time when you secure the pump is the question.