Automotive Air Conditioning Information Forum (Archives)

Accord91 on Thu August 09, 2012 5:18 PM

Year: 1991
Make: Honda
Model: Accord
Engine Size: 2.2L
Refrigerant Type: R12
Ambient Temp: 86
Pressure Low: 12
Pressure High: Unknown
Country of Origin: United States

Greetings:

I'm pretty much all set to do a DIY top off of my 1991 Accord's R12 system. However, I'm unable to connect my high side gauge hose because the hose and fitting are different sizes and I don't know where to get the correct adapter or hose (I've searched online, but there is much confusion).

My hose set fits the low-side fitting, which I believe is 7/16 (threads/inch = ?). Schrader valve connection.

If my research is correct, the high-side fitting is 3/8 (threads/inch = ?). Schrader valve connection.

So, can someone tell me exactly what I need to adapt my existing high-side hose (7/16) to the high-side (3/8) Schrader fitting? Or, is there a separate high-side hose to accommodate the smaller high-side fitting?

Relevant information:

- My low-side static pressure is 90 PSI at 86 degrees F.

- My low-side running pressure at 1000 RPM was around 12 PSI. (I couldn't get a high-side reading: Wrong hose to match the fitting.) At higher RPMs, the low side dropped into vacuum range.

- I concede that I will take the car to a shop if the high-side readings are whacky once I get the adapters/fittings to connect my high-side gauge.

- The AC cooling deteroriated late last summer. I have a little cool air from the passenger vent.

- Compressor and AC fan run.

- I found that my low-side valve had a very slight leak. I tightened the valve with a Schrader valve tool and it is no longer leaking. I suspect that this valve has been slowly leaking for a while.

- I have two 14 oz cans of R12. (I got my Section 609 certification to purchase the R12.)

- The system has never been exposed to air, and until last summer it had been cooling just fine.

- I'm willing to try the DIY approach with full knowledge that the proper way to do a recharge is to evacuate, weigh the refrigerant, pull a vacuum, check for leaks, and re-charge, but this is a 20-year-old around town driver. If this doesn't go well, I'll have the system properly evacuated, etc. There is a guy in town who still has R12 refrigerant and recovery equipment. I'll consider doing a proper R134a conversion, but that decision point is not here yet.

Thanks for any guidance. BTW, I did look through the FAQ and the forum pages, but I did not find info I seek. This is a great forum






Edited: Thu August 09, 2012 at 5:31 PM by Accord91

AutoCool on Thu August 09, 2012 6:02 PM

Accord 91, standard manifold hoses are known as 1/4", that screws directly onto your Hondas LP fitting as you wrote. The high side is smaller, that¨s called a 3/16" fitting. Mastercool sells an adaptor for that called a 1/4" x 3/16" GM Adapter article number 90355. Most AC tool makers have their own version too.

You might want to check your clutch hub clearance on that compressor, too much clearance and they tend to slip when engaging and can heat up fast. Seen lots of fried rubber hub rings, clutch bearings and clutch electromagnets on those cars.

mk378 on Thu August 09, 2012 6:26 PM

There are two kinds of the 1/4 x 3/16 adapter. One has a long probe and only fits certain GM cars. The other one has a standard probe, for Japanese and other cars from about 1988 to the end of the R-12 era. The site sponsor and better auto parts stores all sell both.

Leggie on Thu August 09, 2012 8:39 PM

I had the same issue. My work around was to fit a high side retrofit adapter from a R134a kit. It's just a threaded aluminum ring. Once you have that on,you could clip on a R134a high side fitting.

It's not permanent. You can unscrew it after use.

1976 and later used 7/16 on high side. 3/8 was used on both until then. The reason is that people were rupturing R12 cans by hooking it up to high side which can get close to 400 psi on hot days.

Cussboy on Thu August 09, 2012 10:57 PM

Quote
Originally posted by: AutoCool
Accord 91, standard manifold hoses are known as 1/4", that screws directly onto your Hondas LP fitting as you wrote. The high side is smaller, that¨s called a 3/16" fitting. Mastercool sells an adaptor for that called a 1/4" x 3/16" GM Adapter article number 90355. Most AC tool makers have their own version too.

You might want to check your clutch hub clearance on that compressor, too much clearance and they tend to slip when engaging and can heat up fast. Seen lots of fried rubber hub rings, clutch bearings and clutch electromagnets on those cars.

Quote
Originally posted by: mk378
There are two kinds of the 1/4 x 3/16 adapter. One has a long probe and only fits certain GM cars. The other one has a standard probe, for Japanese and other cars from about 1988 to the end of the R-12 era. The site sponsor and better auto parts stores all sell both.

Yes, there are two types of R-12 3/16 inch flare high side adapters. There's one that fits earlier GM and Toyota. There's another that fits Ford and for the Japanese-made Mazda, like my 1988 B2200. I have both, myself.

Not sure which one Honda would use.

Accord91 on Fri August 10, 2012 10:01 AM

Thank you all for your responses. I now know what I need to look for: 1/4 x 3/16 fitting adapter. No wonder I was confused looking for 7/16 x 3/8. :-)

There are a couple of industrial supply houses in town. Now that I know what to look for, I should be good to go!

You guys are great. Much appreciated!



Edited: Fri August 10, 2012 at 10:03 AM by Accord91

AutoCool on Fri August 10, 2012 12:06 PM

Youre welcome. Good luck.

TRB on Fri August 10, 2012 2:25 PM

90358 Adapter

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Edited: Fri August 10, 2012 at 2:28 PM by TRB