griffiths

For the investment you would have to make in minimum equipment to "properly service" (do the job right the first time) the ac system, (not to mean the mechanical work): the evacuation, charge, test and diagnostic work, it is not effective to DIY unless you plan on servicing a few to several systems per year.

However here is the list:

1) AC Vacuum Pump
2) Service Gauges with Hose Set
3) Electronic Leak Detector
4) Electronic Refrigerant Scale
5) Black Light Leak Detector Kit
6) Refrigerant Recovery System
7) A few traditional books on automotive ac systems
8) Electronic vacuum gauge - micron scale or equivalent conversion scales
9) Liquid Flush Equipment

Now some with rationalize that because of their success in doing a few systems that turned out well that all the equipment is not needed or the level or cost of the equipment could be less (i.e. "you can find this on Epay...." etc.). This may be true for their particular experience with a few cars. What usually happens in the case of poor performance after converting to R134a is often related to a procedure (man or method) or component issue (material). :

1) For example: failure to pull a deep or long enough vacuum can leave residual moisture or air in the system. R134a is not as forgiving as R12 when it comes to residual air left in the system. A mixture such as this causes high side pressures to rise above normal R134a recommended pressures. The residual air in the system could have been related to, (a) on the "material side": a malfunction in the vacuum pump, leaking service gauge set or its hoses, accuracy of analog low side gauge, a leak in the vehicle system, (b) on the "method side": failure to replace compressor pump oil, failure to pull a long enough vacuum, attempting to pull a vacuum when ambient temperatures were too low (in cold weather), or (c) on the "man side", over confidence in capabilities or equipment, rushing the job or taking short cuts, or failing to document data, etc.

2) For example: buying inexpensive equipment and not having test equipment to verify its capabilities; such as a vacuum pump or gauge problem you could trouble shoot with an electronic micron gauge to verify its capability or pinpoint a leak in a section of the service gauge/hose set.

3) For example: problems relating to the use of small cans of refrigerant vs. using a typical 30 lb container with an electronic weight scale. When you need to inject a particular quantity of refrigerant it is much easier to use the later.

4) Failure to follow the procedure of charging by P&T's or Pressures and Temperatures. For each type of refrigerant there is a range of high side pressures that correspond with a given ambient temperature.

DIY projects can be fun, rewarding and save you money. However there certain projects, or portions in the project, that are simply not cost effective for the average DIY.

The hose failure is typically related to time. It sounds like you have the usual needed components. Just make sure you have refrigerant oil (you can use ester) and new o-rings, have any remaining refrigerant recovered from the system before you open it, and schedule your time so you are not rushed.

I have personally converted three of my own sharks to R134a (1978, 1984s and 1989S4) and all performed perfectly up through 95F ambient (I did not have the opportunity to test as higher ambients). As well, many of our clients were satisfied provided the work was properly performed

BlueMaxx

dr bob;

Thanks for insight. Been running the system for 2 weeks with no hitch at all. Hot and humid here in Hampton VA but so far i'm very happy. This was the last Biggie in my quest to restore. Well...there is the drivers sear bolster problem but.......

dr bob

Glad it's working! I have a reasonable knowldege of AC systems, but I'm no Charlie Griffiths. I have no knowledge of seat and upholstery repair though. So while my car is quite cool inside on the warmest days, it has the same driver's seat bolster problems that you mention. So at least it's not the hot seat...


Stay cool!

UKKid35

Are R12 substitues flamable? Here is the Material Data Safety Sheet for AutoFrost

It is decribed as I don't use AutoFrost myself but is should be readily available in the US. I've had Isceon49 (by Dupont) in my car for the last four years, the only problem I have is that my compressor control relay seems to be on the verge of failing.

dr bob

The hardest point to get across to most folks is that, no matter what refrigerant you plan to install, you really need to fix the leaks before you start adding anything. Once you decide to do that, including replacing the 25-year-old o-rings and the perforated hoses, the choice of refrigerants is easy-- choose one that you can get easily and have serviced anywhere. Kinda narrows the choice down to R-12 or R-134a. You need to replace the drier and the compressor oil no matter what, so adding the correct expansion valve(s) is really the only difference.

Can anybody tell me why they would even consider "topping up" with one of the refrigerant blends, especially in your AC system that's already demonstrated its ability to leak?

JHowell37

I've got a couple of my own questions on A/C and I'll just tack them on here rather then starting a new topic. My car had a sticker claiming to have been retrofitted for R-134A about 7-8 years ago. It's leaked out to the point where the compressor doesn't come on when the button is pushed. No surprise. I have a new o-ring set, dryer, and expansion valve. I'm thinking the hoses need replacement as well since they're most likely the originals. I've heard of some people making their own hoses. So here are my questions.

1. How does one get the materials to make their own hoses?
2. How many simply replaced their original hoses with OEM?
3. Are fresh OEM hoses suitable for R-134A?

Like most other people, I really don't like letting others touch my car, and fortunately, most mechanics shy away anyway. Would it be okay for me to install the new parts and then take it to someone else to do the vacuum, charging, etc?

dr bob

Making your own hoses requires the hose material and a crimping tool to swage the sleeves on the ends over your original fittings. Fortunately the services are generally available from industrial hose suppliers if your local auto AC specialist isn't up to the task. Many better AC shops are set up to rebuild hoses so that should be your first stop.

You'll want to befriend that AC shop, since you'll need some of their services getting the AC evacuated, leak-checked and recharged. The costs of buying the tools needed just isn't justified with one recharge or even half a dozen. Look at Charlie Griffiths' list above and you'll get an idea.

the flyin' scotsman

Talk to Roger @ 928sRus............he's in the midst of having the hoses rebuilt using new Barrier type product.

the flyin' scotsman

After Charlie's and dr bobs posts I believe an owner can replace all the parts and then have the system evac, check and fill done by your local a/c garage.The question, for me anyway, is the amount of time from when new parts are installed to the system refill.