str8dogg

I know that this is before the season, but I have a ton of things that I need done to "Bertha". Without going into the whole, a/c shop scenario, would it be possible to recharge an '89 f150 with refirgerant from the auto parts store. If so what kind it recommended, expecially with the changing of the refrigerant by the Federal codes?

dewman

Not sure if you can do it yourself. I know that the older a/c units had freon that you could not buy at the auto parts store. The newer a/c uses a different type of freon to cool the car. I do not believe they are interchangeable. You need to modify the older systems to take the newer freon. I am not sure what year that change occurred so I do not know if you have the older system or not.

Dominick

The older systems used R12 cant get anymore.
The systems can be upgraded to 134a I think its a few O rings and
new compressor oil (have to drain the old)
then vac the system down and refill it with 134a.

Just call me Sean

iTrader: (1)

I've done many a/c changeovers with good results and no modifications. Yes, your system uses R-12 and can't be bought by an unlicensed person. It's also outrageously expensive compared to R-134A. An R-12 system with R-134A in it won't get as cold as it used to but only when not moving but not always. This is because R-134A isn't as efficient as R-12. Newer vehicles have larger evaporaters to compensate for this. If your system is only a little low on charge then have a licensed a/c tech add R-12, but if it's mostly or all empty then you might as well change it over. It will be best for you since you can service it yourself. The most important thing when changing over is to have the system vacuumed and you should not skip this step or compressor damage usually results. Vacuuming removes residual moisture from the system and leaving the vacuum will show if your system leaks. If you have a Harbor Freight near you they sell a very cheap a/c vacuum for around $20. It is a venturi type that requires an air compressor to operate. It's not designed for the professional a/c guy because the air compressor must run constantly for 30 minutes while vacuuming but it's good for occasional use. Doing this initial changeover it would be best to have an a/c manifold since it has the gauges to see vacuum and valves to close off the system, and it allows you to vacuum from both the low and high sides. This isn't required though but without it you won't be able to see if the system is leaking and you will have to adapt the vacuum to hook to the low side with the hose you get with the changeover kit. After that just follow the instructions on the changeover kit.

wde3477

I converted mine from R-12 to R-134 back around 2000.

At the time, the recommendations I received were to flush the lines out, and to change the O-Rings, compressor oil, and accumulator/dryer. The kit I got came with the o-rings and the fitting adaptors for the high and low sides, also bought a conversion kit for my manifold which included adaptor hoses and new gauges with the R-134 temperature bands.

I used one of those air-operated vacuum pumps that Sean mentioned - worked OK - but my little compressor was a-huffin' and a-puffin' but got the pressure down to -29inHg - not perfect, but I guess good enough. Also, the recommendation was to refill at a rate of 3/4 lb of R-134 for each 1 lb of R-12 specified. I went one step further and installed a high-pressure compressor cutout switch. It was also recommended to adjust the low pressure cutout down - IIRC, from about 28psi down to 22psi which related to about 1/8 to 1/4 turn on the adjusting screw.

The compressor shelled out shortly after the conversion, but I suspected it was on its way out before the conversion - guessing the conversion just hastened its demise??? Got a new one from some place in Texas - IIRC - Republic Auto Parts, or something like that - about $200 (remember, this was around 10 years ago).

After reflushing the lines to remove any compressor debris - all has been working well since. True, it doesn't seem as cold as the R-12, but kicking the fan speed up a notch takes care of keeping things more than comfortable.

On subsequent topping off of R-134, I try to get the high-side pressure at or just a little higher than where it ran with the R-12. Perhaps not the correct way - but it works. I know that systems designed to run R-134 typically run at higher pressures, but am being cautious - not wanting to blow the now 20-year-old hoses.

str8dogg

I assume the conversion kit(s) can be picked up at an auto parts store? Would that be the name, "a/c conversion kit"? Finally, am I to understand that there are two kits, one for the high/low pressure lines and one for the manifold? SOrry for the confusion, I am trying to learn "auto mechanics" since mine left and moved to Canada?

wde3477

Might be harder to find since R-12 hasn't been in American vehicles since around 1994 or so - but the kits should still be out there somewhere. I think I ordered my stuff from JCWhitney.

I got one conversion kit for the vehicle - this included the o-rings and the adapter fittings for the high and low side gauge/fill ports. It looked to be a generic kit - oodles of o-rings, just have to pick-n-choose. The difference I saw was that the old o-rings were black, the new ones were a green or aqua colored. The adapters just screw on to the existing ports - this is due to the differences between the R-12 spec threaded ports and the R-134 spec snap-on ports. One nice benefit is that the R-134 ports are different sizes, so if you install them on the right line - won't have to worry about hooking a gauge set up wrong in the future.

The accumulator dryer was picked up at the parts store - I just made sure that it was labelled as R-134 compatible. Not entirely sure this is required, but it was recommended - and I only wanted to do this conversion once. The freon, flushing solution, and compressor oil are also available at the parts store without a license. Make sure the oil is for R-134.

The manifold kit was a conversion for my gauge set - I had an R-12/R-22 gauge set, this kit made it possible to connect up to an R-134 system.

You may want to get a total cost estimate for all the stuff before you decide to convert. As Sean mentioned - R-12 is still available, but very pricey and requires a licensed technician to legally purchase and to install. However, if your system is otherwise sound and just needs topping off, and not a near-total refill - professionally recharging with R-12 may be the least costly and troublesome route, for now. Also, releasing any remaining R-12 from the system into the air is likely illegal - but that's up to you.

There are some R-12 replacement products - I think 'Freeze' is one of them - however, have heard of mixed results, and some of these products are quite flammable. It's another consideration, but I wouldn't recommend them.

If you've already decided to convert - you can do it yourself - just take your time, be careful, and get it right the first time. A set of A/C gauges and an A/C shop manual are good tools to have. Use caution when dealing with the freon - the high pressures and extreme temperatures can cause equipment damages and personal injuries that will end up costing more than having the conversion professionally done. Be sure to wear hand and eye protection at a minimum when handling the freon.

Good luck, and keep us posted.

mitchalvin

When changing to R134a change the orifice tube to the one for r134a. This help cool the vehicle better as it makes the system see a larger evaporator. This is because it creates more of a pressure differential between the high side and the low side.

Just call me Sean

iTrader: (1)

This sounds like a very good tip if it's true. I will have to try this next time.

The conversion kits are still available on the shelf at the parts store. They come with the refrigerant, the adapters and a low side hose to add freon. They may even have an oil charge included, I don't remember but if it doesn't then the refrigerant will have a small amount of oil in each can. If you want the manifold it is sold separately.

Here's my experience with my conversions. When I converted without vacuuming the compressor fried a short time later but the ones I did vacuum they worked fine.

mitchalvin

If you add freon without purging or vacuum after opening the system you will have water in your lines from the atmosphere, this will lead to all kinds of problems with the pump, condenser, evaporator, accumulator, and other parts.