Right after I did the conversion and noticed the poor performance at idle, I replaced my fan clutch for the very reason that testing one is not really an option. It didn't help any. I may try adding an electric fan that comes on with the compressor to see if that will help out so I don't have to replace the condensor, but have not located one yet (it needs to be pretty thin to fit behind the grille). Suprisingly, it's been pretty cool lately with all the rain we've been getting so this has not been nearly as big a problem as it was last year.

 

yeah i hear you about the motorcraft clutches,I went thru 2 different hayden heavey duty clutches that didn`t last a week before failing.

 

So if I wanted to put a 1995 condenser on my 1990 everything will work but the liquid line and would need one for a 1995?I guess the condenser will bolt right in?or do I need to modify something?

 

anyone help me with this?

 

I'm pretty sure you are correct. IIRC, the accumulator for the 95 (R134a service and LPCS fittings) will also bolt up.

 

There's plenty or R12 available.

You can purchase R12 12oz or 14oz cans on E-bay for around $20.00 .
Your vehicle requires 4 14oz cans. $80.00.
If you convert to R134A 4 12oz cans $28.00.

So you save $52.00 on the refrigerant which doesn't include the R134A conversion kit for the fittings and oil.

Fix the leak and stay with R12.

Take the open book test and get 609 certified and you can purchase R12.
http://www.epatest.com Cost $20.00.

 

I used the manifold hose assy. and dryer for a 1994 truck. That all fit perfectly and the high pressure line connects to one side of the condensor, so evidently, that high side of the condensor is the same for 1991 and 1994. However, the liquid line was different (I was replacing mine because it was damaged and I inadvertanly ordered one for a 1994 and it wouldn't fit my condensor) so I believe the fitting on that side of the condensor is different. I am 99% sure that if you replace your manifold hose assy, condensor, liquid line and dryer with 1994-96 units it will all bolt up.

Staying with R12 is not a long-term solution IMO. I would also be wary of 15 year old cans of R12 still being full at this point. We were told (back when I was in the business) that the 1 lb. cans could not be trusted to hold their contents for more than 2-3 years. That may have been EPA scare tactics but just throwing it out there in the interest of full disclosure.

If you wanna stay R12 then I recommend you use R406a, which is an R12 drop-in replacement. I have had good luck with it and it is only about $8 a can IIRC. You do still need barrier hoses to use it, tho.

However, the nice thing about R134a is you can pick it up at Wal-Mart whenever you need it. Sometimes it's hard to keep these old trucks leak-free, especially considering the built-in-from-the-factory leak where the liquid line joins the evaporator core.

 

R406a (Autofrost) contains R22. It is not compatible with the rubber used in MVAC systems. It will attack and destroy the seals.
It is also a "blend", which will fractionate if a leak develops. The oil carrying component, R142b, will leak off first and can starve the compressor for oil.

Contrary to popular belief, there is no "drop in" replacement for R12. Each alternate option has it's own necessary modifications and drawbacks. There is a long list of EPA "approved" refrigerants. The EPA approves them on the basis of how environmentally safe they are. They make no recommedations or claims as to how well they actually work in an MVAC system.

There is enough virgin R-12 available to last the expected lifetime of the vast majority of R12 systems left on the road. As the number of these systems declines in daily use, there should be R12 available to the collector vehicle market for the forseeable future. This also has the happy effect of lower cost due to the decreased demand.
While blends and other alternatives were viable options 10 years ago, they just don't make sense today.

 

It is my understanding this is only true for butyl rubber seals. I don't think those have been used for some 20+ years, have they? Use the blue (neoprene) seals for R-406a and there won't be a problem.

While perhaps true in theory, I have not seen this happen on my 2 personal vehicles that are using R406a.

It's probably good at this juncture to point out that EPA certification is required to legally purchase either R12 or R406a. So discussing further may be a moot point. He asked about R134a, I'm gonna stick to that from now on in this thread.

 

Hey guys I ordered everthing for the ac in the truck,I am going to changeout the evaporator and need alittle help here,to take the box apart I see 2 screws on the top middle where the box splits in two and two of the same on the bottom where it splits in two I see one stud or bolt that holds the map sensor and thats all I can see is there another that I am missing as this won`t come apart somewhere near the bottom?

 

Well, after all these years, I finally swapped out the condensor for a '96 model. It's pulling a vacuum right now as I type. The dang thing never leaked so I did not want to open up the system until I had to when I replaced the wheezer 300 with a 460.

The '96 condensor is NOT a direct bolt in. It hits the brace that runs vertically right in the center of the core support. It was an easy mod to make to space it out about 3/4" from the core support to make room, but just be ready for this.

The bigger issue is that the outlet tube is smaller than the R12 unit. You could get around this by using a '96 liquid line, as I tried to do, but then I found the inlet to the evap core is also smaller. So, you need to replace the evap core OR, what I did was have a custom line made with the little R134a fitting on the condensor end and the big R12 fitting on the evap core end. This was a lot cheaper than a new evap core, and easier.

I thought I should update this thread since my opinion that the '96 condensor would bolt right in was not correct.