Automotive Air Conditioning Information Forum (Archives)

Kchan156 on Wed October 19, 2011 12:08 PM

Year: 1993
Make: Toyota
Model: Land cruiser
Refrigerant Type: R12

So I bought a set of mastercool dual r12 r134 gauges. The hoses says r134. The low side fits but the high side doesn't. I guess it's an 3/16" valve?? My question is can I put a set of r134 service valve adapter on so I can use my gauges to measure my r12 readings?

mk378 on Wed October 19, 2011 4:20 PM

For most R-12 cars after the late 1980's, you need a 3/16 to 1/4 adapter like this one:
https://www.ackits.com/pc/90358/chargeadapter/90358+-+Service+Port+Adapter

But yes you could also put a converter on temporarily. Be sure to remove it after measuring the pressure to avoid confusion.

NickD on Wed October 19, 2011 5:34 PM

It was in the early 60's that GM came with a smaller high side port, so called GM high side adapter.



Can only recall one vehicle I worked on, think it was a Nissan that didn't require this high side adapter. Problem with using R-134A conversion ports, some are self locking, may never get them off. Get the adapter. LOL, talk about inflation, recall paying around 40 cents for these things.

NickD on Thu October 20, 2011 5:28 AM

Ironically for years could buy one set of gauges to service both your home AC with R-22 and vehicles with R-12. Then the EPA comes along and says all refrigerants must use different fittings. Nobody was dumb enough to put R-22 in an automotive system or R-12 into a home AC system.

So we have a whole bunch of adapters to deal with, and any time you had another fitting, increase the possibility of leakage. So we have a bunch of idiots treating us like a bunch of idiots. Then they approve of all these so-called R-12 replacements that aren't worth a crap, so created a refrigerant mixing problem. So now we have problems that never even existed before.

Tried to get a job with the EPA, wasn't qualified, have an IQ greater than two. Only complete idiots are eligible to apply.

Cussboy on Thu October 20, 2011 2:58 PM

Ford had a different R12 3/16 adapter, I still use that on my 1988 Mazda truck that's R-12. I used the GM 3/16 adapter for the high side on my 1988 Suburban when I had that, they are different. I wouldn't know which one an old Toyota would use.

Cussboy on Thu October 20, 2011 2:58 PM

My gauges are R-12, but I have the adapter hoses for R134a.

Edited: Thu October 20, 2011 at 2:59 PM by Cussboy

mk378 on Thu October 20, 2011 3:27 PM

GM is unique for recessing the shrader valve into the port. All other brands should use the regular adapter. If the pin of the shrader valve is even with the top of the fitting-- the same as it is on the low side-- use the adapter posted above.

Edited: Thu October 20, 2011 at 3:28 PM by mk378