Retrofit AC upgrade results

[Backfoot100]

My stock AC system didn't work when I acquired the truck (86 Sub with 350, rear air and an R4 compressor on the drivers side). However, I was assured that the system did work when it was last checked at least 6 months prior.

Living in FL I need the AC to work. I had the original system fill valves upgraded, evacuated, vacuum checked and filled with R134. The system did work great for a few months. Then the compressor seized.

I read through about every post concerning AC upgrades. I read all of the horror stories....
Buy only new and not rebuilt R4 compressors....
R4 compressors are pretty much crap to start with but new ones are even more crappy....
Brand new R4s might last a day, a week or a month....
Some have had good luck with new R4s....
Upgrade to a Sanden....
If the compressor seized you need to replace everything and flush the system completely....
Don't overfill with R134.....
The list goes on.

So I decided on just trying to replace the R4. AC is my Bane and I don't like to deal with it. I replaced the R4, the accumulator and the orifice tube. Then I took it to a reputable shop and they flushed it completely, vacuum checked it for integrity and put a fresh charge of R134 into it.
They found the system to be pretty dirty from the seizure. They flushed it twice to make sure it was clean.
They also found the expansion valve for the rear air was clogged too so they replaced that.
That was two weeks ago and I have to say the system cools wonderfully now. I guess its just a matter of how long will it continue to run.

I've already decided that if this thing ***** the bed again I'll upgrade to a Sanden compressor but that means a new mounting bracket as well as new hoses to the compressor. None of which is going to be cheap but the end results have been favorable for virtually everyone who's done it.
Its not a daily driver so I'll update this occasionally as it gets used more through the upcoming summer. Hopefully others trying to keep their AC systems working will be able to benefit from my trials and tribulations.

 

[idahovette]

Just upgraded my 66 Nova with a Sanden 5 cylinder and brackets all for $300 from Jegs. Not working yet other things to do but this has got to be better than my 50 year old + A-6 compressor

 

[Oaasport]

@Backfoot100 I am in the same boat, except I live in Arizona. I am not only doing a Sanden conversion, but a whole new system upgrade for LMC Truck. I got tired of vaccuum lines breaking, cables getting stuck and only air on the floor. I also have rear air and thats a really nice feature for my passengers

 

[Backfoot100]

Reviving this with some more results hopefully others will be able to use.

The "new" R4 that I replaced after the original seized lasted about 9 months and that one also crapped the bed. What countless others have experienced holds true. New or rebuilt R4's suck......they're all Chinese knockoffs that will eventually crap the bed. Its not a question of "if" but "when".
All the pundits will argue that they're covered under warranty and you just replace them with another piece of crap R4 every year. The problem is you still have to replace the accumulator and orifice tube and then you have to evac and fill the system....every time. Every one of those episodes is a minimum of $175 in my part of the country plus your labor to go through this fire drill every year. No thank you.

I did what I should have done from day one. A brand new Sandon 7 valve compressor (because of the rear air) Suburban that this thing needs to cool. An aftermarket mounting bracket that was pricey but literally bolt on (and before you ask, absolutely no issues with headers, power steering pumps or mounting problems) and new hoses custom made for my application. Put everything on, had the system evaced and filled. Works perfect for two years and counting in FL heat.
The whole new system after said and done cost $700 but I had more than $500 into two failed R4 attempts.
The moral of the story guys is do it once and do it right. Don't poke the pooch. Pony up one time and don't look back.

 

[Craig 85]

I used a Sanden with my OEM set up. Works perfect.

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[Kurnacopia]

How does one figure out which Sanden compressor is right for their truck?

 

[Backfoot100]

How does one figure out which Sanden compressor is right for their truck?

Need to do some homework. Go to the Sanden website. 5 cylinder or 7 cylinder? 5 is fine unless you're trying to cool a Suburban. Then its a matter of V-belt drive or serpentine drive? Mounted on drivers or passenger side? High or low mounts? Headers or manifolds? Do you want to keep it in the factory location or move it to the other side? Seeing as new hoses need to be made, you can change up whatever you want. That's kinda the beauty of it. You wanna keep it pretty much factory V-belt drive, go for it. If you're planning on upgrading the entire factory V-belt drive to a serpentine setup, you can do that too. How far do you wanna go.
A little common sense goes a long way too.

 

[Joshua Keith]

A/C rebuild list. May help someone

1985 K10 SBC 350 This is the list I’ve come up with, but there may be some better deals out there. Prices are with taxes. I will have to get some lines made from a shop once I get it all together. Total price is 523.45 and still needs lines.I know Original Air makes a complete...

www.gmsquarebody.com

 

[blueburb2500]

I used a Sanden with my OEM set up. Works perfect.

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Hey there I was wondering how you did your clutch connection. Getting ready to do this swap myself and I see the Sanden has a one wire hook up but my old Pancake is a two wire.

 

[Craig 85]

Hey there I was wondering how you did your clutch connection. Getting ready to do this swap myself and I see the Sanden has a one wire hook up but my old Pancake is a two wire.

Without going to looking, I believe I just cut the OEM connector off the positive wire and added a bullet type to mate to the Sanden wire. The unit itself grounds through the mount.

IIRC the OEM ground wire terminated on one of the OEM bracket bolts anyways.

 

[SquareRoot]

Without going to looking, I believe I just cut the OEM connector off the positive wire and added a bullet type to mate to the Sanden wire. The unit itself grounds through the mount.

IIRC the OEM ground wire terminated on one of the OEM bracket bolts anyways.

This ^^^^

 

[blueburb2500]

Yep I figured it out I didn’t think it was that simple I was overthinking it.

 

[greatlakes08]

Need to do some homework. Go to the Sanden website. 5 cylinder or 7 cylinder? 5 is fine unless you're trying to cool a Suburban. Then its a matter of V-belt drive or serpentine drive? Mounted on drivers or passenger side? High or low mounts? Headers or manifolds? Do you want to keep it in the factory location or move it to the other side? Seeing as new hoses need to be made, you can change up whatever you want. That's kinda the beauty of it. You wanna keep it pretty much factory V-belt drive, go for it. If you're planning on upgrading the entire factory V-belt drive to a serpentine setup, you can do that too. How far do you wanna go.
A little common sense goes a long way too.

Ive got a 1991 Suburban with rear air. Currently it has been converted with the original compressor still working but its not cooling like I want it to. I would like to do as few mods as possible to the truck in order to achieve cooler air. Can you tell me which compressor you used and where you purchased the bracket? I understand my TBI might have a different layout then your 86 but I assume the the original front/rear AC setup is identical. Any info to save me from hours researching would be much appreciated.

 

[gmbellew]

R4 to Sanden whith stock ac lines(for serpantine)

Went ahead with a sanden change out on my suburban. Kept original lines by picking up a sanden unit with rear line mount and adding inline #8 discharge adapter. I will get part numbers and drawing for adapter plates posted on monday. The pulley on the compressor has extra ribs, but it does not...

www.gmsquarebody.com

this is the info you need for an upgrade and conversion to r134a. you may also want to adjust the low pressure cutoff switch a little bit to further help it cool.

 

[greatlakes08]

R4 to Sanden whith stock ac lines(for serpantine)

Went ahead with a sanden change out on my suburban. Kept original lines by picking up a sanden unit with rear line mount and adding inline #8 discharge adapter. I will get part numbers and drawing for adapter plates posted on monday. The pulley on the compressor has extra ribs, but it does not...

www.gmsquarebody.com

this is the info you need for an upgrade and conversion to r134a. you may also want to adjust the low pressure cutoff switch a little bit to further help it cool.

Thank you very much!