1997 Mountaineer A/C Issues

[donaldbc]

How much do you think a shop will charge to install a new accumulator? Do you have to vacum out everything? How tough is that to do?

 

[Glacier991]

The accumulator will run you $75 to $100 depending. The remove and reinstall will be about .5 hours of shop time. The system will need to be evacuated and recharged. Charge for that varies with refrigerant between $125 and $200 would be my guess. HTH.


Happy Exploring

Chris

 

[donaldbc]

I was reading in the haynes manual abouth the removal and install of the accumulator. It says to take your truck to a shop to get the a/c system discharged by a shop. Then install your new accumulator, then go back to the same shop for the recharge. So, will most shops discharge an a/c? I will want to install the accumulator myself, then recharge it myself using my "at home r134 kit" How does this sound? What will a shop charge? It shouldn't take very long for them to do it?
Thanks Guys
Brian

 

[Glacier991]

Brian.... answers to most of your questions are already in this thread. In an earlier post you mentioned "vacuuming out" like it's simply a matter of sucking out old stuff... it's not. You have to establish a very good vacuum within the closed A/C system before you reintroduce the new refrigerant - that means attaching a vacuum pump and running it a while! V8BoatBuilder used an air powered vacuum pump and got decent results, but I think if he had his choice he would have rather used an electric vacuum pump. He also had a gauge set. Both of those are very important things to have. I think his post is excellent and provides a good step by step "how to". Can you do it with less ? Probably. Will it work as well. No.

Happy Exploring

Chris

 

[V8BoatBuilder]

Chiming back in...

In my case, being a DIY A/C technician means not being the best citizen for the environment. Most of the refrigerant in the system had already leaked out through the rusty accumulator, I went ahead and vented the rest. R134a isn't as bad for the ozone as R12. While I wish I could have recovered it, it just wasn't feasbile.

If your system is almost dry, then releasing a few ounces of R134a probubly isn't that bad. Not great though. Releasing a full system to change a component, that's a tough call - I don't think I'd do it.

When you release the refrigerant, air will enter the system and the system will be at zero psi. Not pressurized, not a vacuum, but still "full" of air. The system is vacuumed so that it is truly empty. Any air remaining will decrease system effectiveness. I was not able to get all of the air out - though I got most

I used a venturi pump on my air compressor. It worked - I can sit in 90 degree heat, in the sun, with a black car, in stop and go traffic, and be so cold I have to turn up the thermostat. However, I've found that all windows and the roof must be closed and the control on "Max A/C" otherwise it just can't keep up. I couldn't find an electric vacuum pump to rent or buy cheap enough. But - if I had one to use, it would have been a no brainer.

 

[dmasini]

I'm gonna bring up an old thread here but I'm curious where I need to vent the system? I'm thinking of replacing the compressor in a friends X. How different are these steps for the accumulator from the steps I would need for the compressor?

 

[MalcolmV8]

Awesome thread. I'm just about to start working on my A/C system. I had it discharged at a local shop before doing the engine swap. Even though they charged me $50 I thought it was better than putting it into the atmosphere.

Anyhow I have a venturi pump just like V8boatbuilder and I too can only get about 25 ~ 26 hg and I have a pretty decent compressor. It stands taller than I do, runs on 220, and moves about 12 CFM at 90 PSI all day long without breaking a sweat. I normally use it for sand blasting. I'd like to purchase a real electric vacuum pump as I do tinker with A/C systems from time to time.

I already have a manifold gauge set and an electronic leak detector.

My questions are
1) Where is a good place to get an electric vacuum pump?
2) How do flush or clean the system out first? I've had it open for about 2 months and been driving it for about 2 weeks. I assume there's dust or other dirt I need to blow out with the air compressor and some solvent. But which solvent? Or does it not matter?
3) How much pag oil do I add to an open system? This is a 94 Ranger originally with the 4.0 V6 now running the 302 from a 2000 Explorer. Compressors look the same and I'm using all the other original Ranger A/C parts which look pretty much the same.
4) Are there any official specs as to what the pressures should be on the high and low side when I charge the system?

Thanks for any info
Malcolm

 

[dmasini]

I hope someone will correct me if I'm wrong but for question #2 I believe I read in another AC post that some have used brake fluid?

 

[MalcolmV8]

Brake fluid? wow I don't know. That would be very hard to get out. I was thinking of something more like acetone or any other solvent that will evaporate at room temperature. Seems like brake fluid would leave an oily residue? But I don't know, just guessing here.

 

[Glacier991]

First off, an electric vacuum pump can be had on E-bay for between $100 and $200. There is a "new" one for sale relatively cheaply... it seems a tad small HP wise, but claims to have a good drawdown vacuum number in the micron range...you may need to run it 45 mins or so, but it should be ok.... here's a link, you can also do a search on E-bay for vacuum pump
http://cgi.ebay.com/NEW-MOUNTAIN-1-...558064888QQcategoryZ66999QQrdZ1QQcmdZViewItem

DO NOT USE BRAKE FLUID as flush. Brake cleaner maybe. I recommend you buy a quart of commercial flush and look into a flush gun, or borrow mine. It'll set you back $15 for the flush fluid. You also might want to change your Orifice tube.... I can send you one for 134a. I think they cost me about $3.

Since your system is empty, recharge by weight. Pressures will depend on too many variables to tell you much, and the low side pressure switch will be cutting out frequently if it is cool outside.

The quantity of R-134 should be 75-80% of the R-12 quantity. Oil should be the same (7 oz I think - spread it throughout the system). THAT data should be in your CD !

There is a long A/C thread in the Useful threads (Now in this forum as well)that should serve as a good educational tool for those curious about A/C. Although it is about converting to 134, it covers all the A/C bases.

 

[dmasini]

I thought I was way off base but I just messed up the whole fluid and cleaner! Here is a quote from v8 boatbuilder:

I used brake cleaner and compressed air to flush the systems when I did the Peugeots, but I've heard other people say use Isoproyl Alcohol, others use a dedicated AC flush chemical...

I got it from this post:Converting an R-12 Air Conditioner to use R-134a

 

[MalcolmV8]

Thanks for all the info guys. I'll be buying a vacuum pump soon enough. Wow that one you linked to was only $124? They used to be much higher when I looked a few years ago.
Oh and FYI - my truck was R134a from the factory.
Glacier, I'll see if I can get the CDs loaded tonight. We're remodeling the inside of our house and it's a disaster right now

 

[leenoack]

I have a question about this repair. I was always told that you should not have the A/C in MAX position when charging the A/C. The MAX position tends to pull cool air into the evaporator when warmer air is preferred which theorectically increases the systems ability to take in freon. Is this correct?

 

[Glacier991]

I think there might be a smidgen of rationale to that old wives tale....(more in terms of how quickly it will take the charge)...but, let me add my 2 cents worth.

If the system is empty, adding by weight is the best way to charge it. If you are topping off, you are going to want to try and fine tune the charge. Too little and you do not get cooling across the entire evaporator, and lose cooling capacity. Too much and you flood the evaporator, also losing cooling capacity.

I recommend fine tuning under real world conditions. That means if you are checking vent temps, you should try and simulate the actual operating conditions... fan on the cooler, and maybe AC set to MAX, if that is how you run it.

Actually, even though you DO recirculate cabin air in MAX A/C... which WOULD be cooler... the airflow is also higher... I bet the difference in heat removal in the evaporator is not all that great between the two unless the outside air is 90 degrees or higher.

Was that confusing enough for an answer ?

ps. Your question rather suggests a belief that the more refrigerant you can get into the system, the better. Not so. There is an optimal amount.... too much is bad, too little is not good either.