Damaged AC Line?

[CraigK]

Rather than add to the great thread below, I thought I'd start my own. My AC situation . . .

Bronco II, 1987, AT, 4WD.
I recently had the passenger side front suspension coil bucket rust in half and break, and my front suspension collapse while driving. When I went to repair this I discovered 1) a hole in the top of the wheel well where the top of my shock absorber mounting bolt pierced through. Looks like it also managed to hit and damage a metal line running on top of the wheel well on the inside in the engine comparment, 2) a big puddle of pinkish oily fluid directly underneath.

At first I thought the puddle was ATF, but it appears to be from an AC line going to the evaporator? Does this sound like what would happen?

I converted to R-134a a year or two ago, and except for having to "top-up" about once a month or so during the summer, the AC was working A-OK. My AC will not engage the compressor now (at least on the latest warm day I treid to turn the AC on).

If I have damaged the metal line going to the evaporator (the large box on the firewall?), what are my repair options? Any help appreciated.

CraigK

 

[RobbieD]

At minimum, replace the damaged line and replace the drier; evacuate and recharge the system. Sounds like you lost some referigant oil, too, which is tough to guesstimate how much to add to bring it back to spec after a leak.

But, really, you shouldn't have been needing to occasionally add referigerant before to keep the system operable. Do you know if all of the o-rings were changed when the R134 conversion was done? When an R12 system is changed to R134, all of the o-rings should have been changed, as the originals aren't compatible with R134.

In repairing this damaged line, you may want to consider this approach- replace the damaged line (with new o-rings), replace all the remaining o-rings, remove and drain the compressor of oil, install the new drier, then add the specified amount of new oil, and evacuate and recharge. This way, you'll stand a good chance of fixing the slow leak, and a lot more likely to get the correct amount of oil in the repaired system.

 

[CraigK]

RobbieD

Thanks for the info. A few questions?

I have looked up some of the parts on LMC Truck, AutoZone & Advance Auto websites. Which line (suction? discharge?) runs on top of the wheel well and goes into the bottom of the evaporator? Should there normally be oil in this line? Also, why replace the dryer (not that expensive)?

FYI - I did the R-134a conversion myself, with a WALMART-ish "AC Conversion Kit for Idiots" or something like that (my level of understanding of AC systems). First was screwing on new fittings on the valves. Then the system was emptied by releasing the pressure (not much left at the time), and simply refilling with the kit contents. Then a few days later I emptied the system again (push the valve, release the gas - yes I know this is an environmental no-no) and refilled with R-134a again to get out any remaining stuff. There were no replacement O-rings included, so no O-ring replacement. This has worked fairly well for two years (although never really as cold as before), except for the monthly, ~1/2 can top-ups during the summer, which I had to do with the old stuff anyways (until I ran out of all the R-12 I had hoarded).

Is a special tool needed to disassemble and reassemble AC system joints? Also, if I buy a set of replacement O-rings for my vehicle (1987), are they likely to be the R-12 compatible rather than the R-134a type? Is there a way (color?) to tell them apart? Also, have you any experience with the short AC tube repair kits? These are for (I think) replacing the short piece of tubing that contains the orifice fitting. I think this is the area that might be damaged, very close to the bottom tube coming out of the evaporator, and I thought it might be a good idea to install one of these to facilitate future orifice replacements, if ever needed.

Also, what is the difference between a standard orifice tube ($4), a "severe duty" tube (~$30), and an adjustable tube (~$30)? Might any system performance improvement (cooler) be available by installing an adjustable or severe duty orifice tube?

Again, any help appreciated.

CraigK

 

[reno]

Well you should be careful admitting to releasing refrigerant into the Atmosphere, one could collect a nice reward for turning you in and you will get a heavy fine.
There are A/C tools you need, they are cheap,they open up go around the line then you just simply push them into the fitting releasing the coupler so the line comes apart.

You replace the Dyer whenever the system is opened the the Atmosphere for any amount of time, moisture is a killer to it. If you decide not to change it, it is your risk 100% of destroying your system,mainly the Compressor. A standard Orifice tube will do. And Autozone sells a package of O-rings fairly cheap. As for knowing what ring goes where,you simply size them up with the one that you removed (do one at a time). O-rings are O-rings, they don't care if it is R-12 or R134A or just oil, they do what they designed to do until they dryout and start rotting.

You should not have to keep adding refrigerant to your system, that would be like having to add water to the radiator every month, would you just not worry about that and keep driving?

 

[CraigK]

reno

Thanks also for the info.

I don't have a problem with replacing the dryer, just wanted to know why. I'm guessing it contains a dessicant chemical (anhydrous something) that absorbs water that would be saturated if opened. ???

Do you know exactly what the difference is between severe duty, adjustable and standard orifice tubes? Again, I'm guessing adjustable orifice (hole) size. ??? What difference might this make? If using R-134a with an orifice tube specified for an R-12 system, might there be a performance advantage to an adjustable tube? "Tune" it closer to an R-134a orifice diameter? Bigger? Smaller? The same? What is Severe duty? Bigger? Why? What impact on AC system efficiency? I don't know, just asking.

And as for running an AC system vs. a relatively costly and time consuming repair, it's a simple cost-benefit thing. For example:

Let's say I have to top up the AC system 4 times during the summer (was probably twice last year) at 1/2 can per top-up, at $10 per can. About a 10 minute job, mostly done while I'm doing something else. Total cost: $20 and 40 minutes tops per summer.

Buy special tools, buy repair kits, tear apart my AC lines, refill entire system, new dryer, new oil, several cans of refrigerant, etc. etc.. If possible for a home mechanic who has never done this before to do, probably at least a full days work (realistically), if not a weekend. Cost ??? north of $60-100??? (Real cost).

It is NOT the same as running a leaking coolant system. Possible terminal engine damage, if not serious performance penalty for running with coolant leaks into the oil or combustion chamber. More like, would you rebuild or replace every engine that burns through a half quart of oil for six months during the summer?? Probably not.

I know from personal experience that neoprene (usually black in color) o-rings will rapidly deteriorate in solvents and chemicals that silicone rings will withstand. And teflon rings will withstand chemicals that neither neoprene or silicone rings can. Someone in an earlier post indicated that the earlier R-12 type O-rings would not withstand the R-134a refrigerant. Again, I'm not sure if this is true or not, but I do know all O-rings are NOT the same. Can anyone with an AC system originally designed for R-134a tell me what color the O-rings are? Thanks.

CraigK

 

[RobbieD]

It sounds like the line that busted is the high pressure liquid line between the condensor and the evaporator. Part # 50-2820 in the LMC catalog that I have, but you might also want to check with the discount parts stores for it.

As pointed out already, you'll need a set of spring-lock coupler tools. Easy to find, and inexpensive.

Regarding the o-rings, I don't mean to ruffle any feathers here, but I've always went by what Ford says in their R-134a training manual: "New hydrogenated nitrile (HNBR) o-rings have replaced the old epichlorohydrin (ECO) o-rings which are not suitable for use with R-134a systems." The manual states that ECO o-rings are not compatible with R134, and Ford even used the HNBR o-rings in late R12 systems, claiming that they seal better than the ECO rings. The HNBR o-rings are green in color. Anyway, it's not that hard or expensive to replace all of the o-rings, and doing so might fix your system's slow leaking.

You're right, that the drier contains a dessicant, and when it's saturated it's done. It's also important to get the remaining original mineral oil out of your system, and replace it with an oil that's compatible with R134. I've used the Ester oil and haven't had any problems.

I have used the severe duty orfice tube, but I don't think the difference is worth what they cost. In my opinion, if you're going into the system anyway, just put a new standard orfice tube in; it's worth the few bucks cost.

Finally, if you haven't already, do read MAKG's sticky article at the top of this forum section, and good luck.

 

[reno]

You can think retopping a leaking system is cheaper than fixing. First you are knowingly releasing Refrigerant into the atmosphere, and by having a leak you are introducing moisture into your system and sooner or later, will destroy a $300 Compressor. But if it is more economical for you, go for it, you asked and I tried to tell you what i have learned so far.

As for the differences in the Orifice tubes, Makg would be the one to ask that, I have been teaching myself A/c's, and this is what I have learned.

 

[MAKG]

I've used the "self adjusting" orifice tubes, and I really don't like them much, since I can't time the cycles anymore (the stock tables don't work). I also noticed NO difference.

So I use the $2 fixed orifice tubes.

The liquid line (NOT suction and NOT discharge -- those are compressor lines) is likely at fault; on 1987s, these contain the high pressure test port. These are not very expensive. If the break is on the other side of the union, you need an evaporator. The PITA factor is large for those with the engine installed in the vehicle (not impossible; just a nasty contortion).

LMC is NOT a discount parts house. They are a restoration house. In many cases their prices are as high as the dealer's. Go to a good local parts store.

I second the motion for fixing it right. You will eventually let the oil charge get too low, eat the compressor, and foul the entire system.

 

[CraigK]

MAKG, reno and RobbieD

Thanks again for your continued thoughts and help.

I was able to feel down where the damaged line is, and MAKG was correct, the damaged section is on the long metal line leading into the evaporator that is actually part of the evaporator, rather than on a more easily replaceable hose/line. (CRAP.) So it has to come out for repair. (Heavy Sigh.)

When you say PITA, what is involved in removing the evaporator? Can the plastic box be simply split and pryed open enough to get the evap unit out? (Engine is staying IN the vehicle!) My new plan, based on my VAST knowledge is to remove the evaporator, replace the damaged section with one of those repair tube kits (~3" of tubing), and re-install the repaired evaporator. I will replace as many O-rings as are needed to get this done. (Maybe more if I get the hang of it.) Also, where is the darn dryer located? I can't seem to find it, and will definitely replace this too.

Current questions:
Where in the system is the orifice tube located? In this straight section of tubing leading into the bottom of the evaporator? Do you know the location (URL) of a good picture of the AC system for this vehicle? (This is one value of the LMC catalog!) Should I order an orifice tube for an '87 system? (spec'd for R-12) Or is there a model and year of Ranger that I could specify to get an orifice tube specified for an R-134a system that would fit into my system's tubing? (This is one reason I thought an adjustable tube might be a good investment.)

Any help MUCH appreciated.

By way of explanation, my B2 is an 1987 with a significantly rusted body, badly leaking exhaust system (manifolds to Y-pipe), dripping valve cover gaskets, etc. etc.. Just keeping it running takes up more time than I have to spare, and the book value of this vehicle is likely less than the value of the tires and the CD player! It is my back-up vehicle, and costs likely one-third its value per year just to maintain insurance. I do all work on it myself, have very limited time - at least until after June, and as such have to make time/cost/benefit decisions on repairs that favor "keep it running" vs. fix it now the way it should be done ($$$ and time). If I can get the AC running again at a limited cost and effort, and just keep it going by adding a bit of refrigerant every now and then, I know it's not the optimal way to do it, but will be the best choice given my current time and $$$ constraints. (Good news is there is only 125k on the motor, so it's still relatively fresh.)

CraigK

 

[MAKG]

The orifice tube is probably right underneath your break.

I'd get the one for your application. It's simpler, and will work decently.

The case unfortunately cannot always be just split with the engine installed -- though you should try it (it doesn't work with a 4.0L, but you have a 2.9L and it doesn't have that %$@#^%$&*$&^(&*) coil pack in the way and the exhaust manifold may be further away as well.

I had to remove the airbox, pull the blower motor, separate the evap box from the firewall (one bolt is only accessible from under the vehicle, another from INSIDE, under the glovebox -- there are a total of four nuts to be removed), and THEN separate the two halves.

An advantage here is that you can clean out all the leaves that typically get lodged in there.

 

[RobbieD]

On my '90 B2, I pulled the passenger side valve cover (for more clearance) and the wheelwell liner (to access housing bolts), and was then able to R&R the evaporator without too much trouble. Hope this helps in your case, CraigK, and good luck with it.

 

[shadetree]

If you convert to R134, the red orifice tube would be the choice as opposed to the blue. There will be those who tell you it doesn't matter, but it does. The blue will still cool, but not as well as the red. shady