R-134a conversion question
 

I'm working on reinstalling Air Conditioning into my RX7. Before someone starts telling me about not bothering with A/C, sticking with R-12 or about the disadvantages of converting to R-134a, please kindly save it for later. I've been doing research and gathering parts in preparation for performing the work.

I'm using a Sanden from a 1989 Non-Turbo. My question is should the compressor's seals be changed out? I'm not referring to the o-rings that seal the hoses (those will be replaced), I'm talking about the gaskets and seals.

Yep get green ones. sorry didnt read through

Since you don't want expert help, I will leave it up to the inexpert help that this post will attract.

No need to be techy :-). I welcome any expert advice.

I just want to know if I can get away with running the Sanden SD708 compressor (from an '89) with Ester oil and R-134a as-is, or if I should replace the gaskets and seals. If so, is there a kit for the Sanden SD708 that has all the gaskets and seals I need?

The oil is going to be changed out with Ester oil, not PAG. All the o-rings are going to be replaced with green ones, which are already on hand. There will be a new expansion valve, accumulator/driver/receiver, rebuilt compressor hoses, low-high pressure cut-off switch, and all remaining lines and parts flushed with A/C flush. I've considered getting a parallel flow condenser, but there's nothing that's a direct bolt-in for the RX7, and you'd have to have hoses fabricated.

According to multiple posts on the topic, there's plenty of good advice and suggestions on alternate refrigerants, such as Freeze-12 (which I considered, but dismissed because I'd be on my own with charging and discharging the refrigerant and servicing the system).

However, there are no specifics and only advice on what to do in general terms. So, I thought it would be a good idea for me to do the work, and then post what I did and the results. The posting is going to contain information specifically related to what parts I ordered, what decisions I made, and the costs involved. I'm still a few weeks away from doing the work.

I can already tell you, DeOxit contact cleaner is great for restoring a fan control switch without dismantling the Logicon.

I'm sorry if my initial post was less than professional. I'm not out to offend anyone.

http://www.uacparts.com/catalog/home...ly_Sanden.html

I know nothing of a/c, but I like looking things up on GOOGLE. I did once upon a time buy one of these kits to overhaul a Sanden. I don't remember it working out that well. Kinda foggy in my memory as to what happened, other than...........it didn't happen in the long run. Think I had problems with taking the clutch off to replace a seal. Foggy. Didn't matter. It's a mild climate in Tx.

There are gasket kits, and new main shaft seals, available from multiple sources. One is ackits.com... some of the new seals indicate that they are compatible with R134. The original seals were not; I am told by an expert that a seal intended for R12 will fail prematurely if used with R134.

There are special tools necessary to disassemble the 708. The clutch puller kit is available as a loaner from Autozone. You will need snap ring pliers to get the seal retaining ring out.

Sanden has a complete maintenance manual for the 708 on their website; I highly recommend you read it before you begin, it doesnt come apart the same way as most compressors.

I would not bother doing the remaining seals (other than the main seal) if the pump was working properly before, but that is up to you.

Some sources recommend that all the hoses need to be replaced with barrier hoses; the R134 molecules are smaller than the R12, and supposedly bleed out over time. I have not done that on mine, but that is the guidance.

I found that adding a condenser fan from an automatic RX7 helped considerably. Another mod that has been recommended to me (to help make up for the lower efficiency of the R134) is to go to a parallel flow condenser; they are supposedly 30% more efficient than the original condensers.

Well, I'm starting to think that getting a reman or new compressor is going to be the way to go for a lasting conversion. I looked into buying the service tools, and between them and the seals and bearings, the cost is almost as much as a compressor. In fact, the master service tool kits for a Sanden 708 are over $350.

I am definitely going to have the flex hoses rebuilt with barrier hose.

Clearly, anyone who wants to rebuild their A/C and convert it to R-134a and expects it to be cheap will find themselves wrong.

It just occurred to me that I haven't really examined the compressor itself to see if it's an original or a reman. It's probably not the latter, but it's worth checking out. So far, I only know it's a Sanden SD708, from an '89, and I didn't read the entire label.

my TII is running r134.. all i did was replace a few leaky o-rings in the lines in the engine bay, pulled about 30in vacuum, and charged it up to about 45psi on the low side. I get <40F at the vents while idling, had no problems for over a year so far. not sure which compressor i have, whatever the 1988 TII came with

Just buy a new set of o-rings. it will work fine.

as for the one on the compressor, Buy new seal for it and thats all it needs.

flush the compressor 2-3 times with Ester oil, clean your condenser with cleaner from autoparts store (they sell those, 10 bux a can I think). then run the compressor with R134a couple of times (just trying to flush the junk out), then finally install a new dryer and run Ester oil and pull deep vacuum like 29 to 30 for at least 30 minutes, make sure no leaks, then fill it with Freeze12.

Im inexperienced. jackhild59 is the expert on A/C :)