... I was looking for this thread from way back...

OK, I know you're supposed to bring the system down to a vacuum for x amount of time (how long again?). Are there any vacuum pumps (manual, electric, whatever) that do the job at the price range of a DIY'er?

edit: (In case the pumps are expensive and that is not an option) Assuming no leaks, what would be a fair price for a professional to do it?

 

harbor freight is your friend

 

I have one strong recommendation for tools and supplies: Arizona Mobile Air www.ackits.com

They sell manifold gauges and vacuum pumps (you need a good strong one to pull a vacuum).

The Heating and AC section of the FSM is your friend. The information for the S5 is also applicable to the S4.

 

Yeah, googled ac vacuum pumps and got a few HF hits. There's one across the border in Buffalo I've been meaning to check out. None in Canada (at least in Ontario AFAIK), but we have a similar place called Princess Auto.

Nice info. Will add to my Auto/Air Cond Bookmarks folder

 

thanks for bringing this thread back as it was just what i was looking for.

i've let my ac system go from somewhat cool to non existent over the last 2 years..

i think i'm going to try freeze 12.

 

Before switching refrigerants, download the A/C Heating Section of the manual and go through the troubleshooting section to determine why. Decline in performance could be due to a leak or, if the car has sat for a long time, the refrigerant had seeped out. I had a 300ZX that sat for five years and the A/C didn't work because there was no refrigerant in the system.

Tidbit about refrigerants: Ester oil is the safest bet when working with R-12 or converting to R-134a or an alternative refrigerant.

Tidbit about compressors: OEM compressors, whether new or used, are the best ones to get. Remans are only as good as the rebuilder. I can only recommend Arizona Mobile Air in regard to remans. On used compressors, change out the oil. On new ones, take note of whether they're shipped dry or not. If dry, fill with 3oz of compressor oil, otherwise find out what kind of oil is in the compressor.

Tidbit: When replacing seals or installing conversion fittings, use Nylog Blue (for R-134a or alternatives) or Nylog Red (for R-12 or mineral-based refrigerants/oils) on the threads of the schrader valves (not the line fittings) and coat the o-rings.

Tidbit about R-134a conversion fittings: Get only good brass ones. Before installation, you will have to remove the original R-12 schrader valve cores using a $5 schrader valve core removal tool available at any auto parts store. Otherwise, the conversion fittings will not fit or work correctly.

Tidbit about converting to anything other than R-12: Install a high-low pressure cut-off switch. AMA http://www.ackits.com/ sells them with a R-134a conversion fitting. Wire in place of the original low-pressure factory cut-off switch in the nose near the accumulator. Don't forget to remove the schrader valve on the high-side line before installation.

Tidbit about when to work on systems: Avoid opening or filling a system during or after it rains. Moisture is the enemy to an A/C system. Keep protective caps on all major components or the system closed until you are ready to do installation or other work.

 

Good Post.

Suddenly, I don't feel so alone.

I can endorse nearly everything in this post. I have been recommending ACKITS.COM, nylog, Ester oils and pressure cutout switches on conversions for a long time.

One small addition/correction. While you can replace the OEM Pressure switch, I would recommend wiring the new high switch in series with the OEM Switch. That is just a personal preference of mine-to leave the oem wiring as original as possible.

 

Speaking of OEM, stick with OEM parts as much as possible. I still had my original evaporator and expansion valve, but decided to replace them since they were left open to the elements for several months. The replacement evaporator, a Chinese-made unit, fits in the evaporator case, but not as well as OEM. Otherwise, it works fine.

I would've kept the original pressure switch (in fact, I have a new one), but I had to give up the switch when I had adapter lines made for the parallel flow condenser that I put in. The hardline with the pressure switch has an odd-ball angle #6 fitting, so I had to cut off just above the pressure switch fitting.

The A/C wiring is still stock--I simply extended the new switch's harness and crimped on two 1/4" male quick-disconnect terminals and plugged it into the pressure switch connectors; then sealed it with self-fusing tape. The specs on the high-low pressure cut-off switch's low cut-off point are only a few PSI higher than the original.

Refrigerant is Enviro-safe (only one can was used) with a touch of propane left over from pressure testing with a total of approximately 5.5-6 oz of Ester oil in the compressor and accumulator. I was originally going to run R-134a (in fact, I was going to do a write-up on a proper R-134a conversion and its results), but a good friend of mine suggested that the Enviro-safe would do a better job.

The condenser I used was AMA part #12-0544C (21" W x 14H x ~0.5" thick), which is a bit taller and thicker, but narrower than the stock condenser. You might go with a unit that's a few inches wider, but bear in mind that need a few inches room to install the fittings; I got a condenser that was too wide (a Polar Bear unit suggested in another thread).

I'm still running the original stock radiator, (newer) OEM hoses, thermostat and water pump and had a maximum water temperature of 200 degrees F on a sunny day around 90 with high humidity with A/C on max at cruising speed 55-60. In a black car with a glass roof on a sunny day, I was comfortable.

 

For a quick performance test, simply start your car, throttle up to 1500RPM for 5-10 min while inserting a cooking thermometer into your middle vent. Your thermometer should drop to around 40-45 degrees fahrenheit. If it doesnt, its TOO hot. What you do next depends on how badly you want/need cold A/C. IF you fail above, find a set of gauges and hook them up. at rest, your pressures low and high side should be pretty much the same (normally 50-100psi depending on the vehicle). Then, start the car and run the same as above while viewing the pressures. A/C systems have different specs depending on the system and refrigerant used, be sure to get this right. Pressures and temps of hoses will tell you EVERYTHING you need to know from here on out.

When working with these older systems, again it has to be noted that in order to use R-12 in your system, you have to be licensed to buy it (already stated WAY back). That being said, 12oz of R-12 is twice the price or R 134a. Contrary to belief, it DOESN'T cool any better, its just harmful to the ozone. If you are out of refrigerant you have a leak. If you have to refill, remember your parts are already old and should probably be replaced anyway. If you dont, or you dont have a leak, R134a requires higher pressures than R12, and the new pressures WILL blow through the old seals. When replacing ANY parts in an A/C system, you should always replace the receiver/dryer (or accumulator depending on the system you have). The older the system, the less useable the dessicant... Not to mention, your orifice tube is probably gonna be clogged up too forcing your cooling temps UP. To sum it all up, giving the age of any FC, it is best to do a complete retrofit (compressor, orifice tube, receiver/dryer and all "o" rings). It may cost a little bit, but you will thank me later... Make sure that once all the parts are replaced (RECEIVER DRYER LAST BEING SURE TO SEAL THE SYSTEM RIGHT AFTER), be sure to vacuum the system out to 25-30" Hg for a minimum of 30 min to get ALL the moisture out of the system or your pump will blow and then due to metal shavings in your system, you will have to start the WHOLE process over again and no parts warranty will cover that mistake......

If you have any questions, feel free to PM me

 

wow i didn't expect that many responses. thanks for all the info. I'll be sure to read the troubleshooting guide. tho i believe (or hope) that it has just seeped out. I'll try to check the pressure tomorrow to see if it holds.

also, i just got a new piece of info. my car currently has F12 in it. apparently guy i bought it off of had a friend in the heating/cooling industry or something and could get it cheap. does this change anything i need to look for?

 

That depends. Was there any other work done on the car's A/C system? Were the o-rings and accumulator/drier/receiver changed? Do the compressor hoses appear to be in good condition with no cracks or other damage?

Freeze12 is a blended refrigerant (HCFC 142 and R-134a) and others on this forum have claimed good performance and a "drop-in" replacement for R-134a (ironic considering) without any changes to the stock system. I almost went that route myself when I decided to put A/C back in my car; simply run new seals, oil, drier, and away I went. I was delayed by an unrelated problem on a different car, which gave me a lot more time to research.

Given the fact that Freeze12 contains R-134a and its molecules are smaller (and could therefore seep out through the 20+ year-old stock compressor hoses), and concerns that the stock serpentine condenser efficiency may not have been up to snuff, I felt that it was not really a good idea to use; at least not in a stock system without new seals, drier, high-low pressure cut-off switch, and rebuilt hoses (barrier hose such as Goodyear Galaxy or Gates).

Ultimately, provided you do what I mention above, what refrigerant you choose is a matter of personal preference. Some think that R-134a or Envirosafe will work just as well provided you retrofit a parallel-flow condenser (I can attest to that) for increased efficiency.

It should also be noted that if you run anything other than R-12 or R-134a, it can not be legally reclaimed and recycled. So most, if not all, shops will not service a system with an alternative refrigerant. You will be on your own for filling and servicing.

 

*sigh*

I'm sure you mean well. You may even be an experienced MVAC guy. But you are passing bad info.

R134a doesnt require higher pressure- look at a t/p chart. It RUNS higher pressures. You cannot avoid this. The FCcondenser has inadequate capacity to run 134a.

Also your advice to replace the orfice tube is faulty . Have you ever worked on an FC a/c? The FC doesn't have an orfice tube. It has instead a TXV. Big difference. And before you say 'same thing' no it's not. We are advising/helping out by passing good info to those who need it. Bad or misleading info is enshrined forever on this forum due to the 15 minute editing lockout.

Don't post if you don't know.

Thx

-jack

 

By the way, this is a picture of a Nippondenso A/C compressor from an S4 Turbo II, courtesy of a pic taken by JSSense's TurboII restoration thread.

http://i150.photobucket.com/albums/s...k301/023-1.jpg

 

has any one ever rebuilt their ac compressor? As opposed to buying a reman for 200+ or new for however much that costs?

If so, links to rebuild kits, and how hard was it?

plz and thx

Thomas

 

I looked into doing that, but while seals and bearings for Sanden compressors are cheap, the tools required to work on a Sanden compressor are not. The bearing and seal tools for a Sanden SD-708 cost over $400 when I last checked. A used unit or reman would cost considerably less.

 

Just buy a used compressor from this forum. They are readily available. Just make sure you get the correct compressor and that it spins freely.


All those northern guys (cluosborne and pfsantos excepted) don't really need A/C, since it never gets hot up there. They mostly rip 'em out to save weight. Often the power to weight ratio approaches that of a modern Honda Fit...

 

I got a used system from an S5 vert (i believe its a sanden, the ports are on the end of the compressor). I had the system evacuated and what not. The vacuum I pulled for about an hour, and refilled with r134a.

It is semi cold, nowhere near where is should be though. But when the compressor kicks on at various RPM's it squeals really bad.

Would that be just the clutch? or the whole compressor?

 

The squealing could be due to a loose accessory belt. Make sure it's tightened to spec (and don't overtighten)

Is the A/C system in the car completely stock, including the condenser?

If you want to run R-134a, you have to do a few things:
1. You'll want to flush out the lines--pull the evaporator core, remove the expansion valve-- and use proper A/C flush
2.. All the o-rings, including the ones in the cooling unit inside the dashboard, have to be changed to R-134a-compatible (green) o-rings. Coat them with Nylog blue. Otherwise, it'll leak.
3. The stock condenser isn't efficient enough to handle R-134a, you'll want to retrofit a parallel flow condenser. Adapter hoses will need to be made.
4. You need to have the compressor hoses rebuilt with barrier hose. Otherwise, it'll seep out.
5. Install good brass R-134a conversion fittings and install a high-low cut-off pressure switch. Cheap aluminum ones will leak.
6. Remove the A/C compressor and change out the oil with Ester oil.

I have already succeeded in retrofitting a parallel flow condenser, though I ended up using Envirosafe instead of R-134a. I still have diagrams and parts lists of the adapter hoses and other supplies needed.

 

squealing is only with the compressor on. The belt is to spec.

Links to proper setup that you were detailing for proper r134a conversion?

 

Then it could be a bad bearing and not the belt.

I don't have any online links yet.

If you're looking to retrofit a higher-flowing condenser, the attached PDF has part numbers, vendors, and prices. Mots of what's in the list is applicable to both S4 and S5 systems. I'm not sure, but I think the S5 vert has a Nippondenso compressor. I posted a link to a picture of a Nippondenso compressor.

One more thing: the list is mostly complete, but don't take it chapter-and-verse.

 

Thomas-
The squealing is due to high pressure, which is due to the R134a being overfilled. If you reduce the charge, the squeeling will go away, but the car still won't cool properly. you could convert to a parallel flow condenser-if you do the car will cool fantastically on R134a. It is a lot of work and expense-frankly a pain in the ***.


One easy solution is to charge with Freeze12. I really don't like to see people using ES12 or any of the other hydrocarbon (ie fuel) refrigerants. I have extensively tested several of those HC types. My biggest beef is that they do not perform well in Texas Heat (104* today and 108* tomorrow, any question?). They also well, they are also fuel.

But...there is another way....

I am going to start a new thread regarding a different refrigerant!

It has very, very nice pressure/temperature characteristics.
It cools great.
It is cheap, less than 1/3 the cost of R134a.
You can buy it anywhere. ANYWHERE!
You don't need an EPA license.
It does not support combustion.
It is compatible with Synthetic oils.
It can replace R12 or R134a in any system currently on the road.
I am currently running it in 2 FC's and 1 other R12 cars.
Performance is similar to R12.
I have trialed it in factory R134a systems where it works fine.

Stay tuned folks!

 

Jack, I must know what you're using!!!! Impatient!

I'm using Freeze 12 with great results. 40 ish temps in desert heat (100's daily)

 

Freeze12 is da bomb.

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/hows-your-c-doing-759808/

New thread coming...

 

i have a question.. I disconnected the LOW and HIGH pressure hoses from the compressor when swapping the engine, and now it leaks. but i cannot remember if it had a O-ring...

 

Yes, there is an oring on each connection.