AC Compressor rebuild for an '84 Carrera

[kilodawg]

I have an '84 with a Nippondenso compressor and I'm still running R12

I'm debating starting in on compressor rebuild. I am curious if anybody has used the tech article to perform the shaft seal R&R, what your results were and how well it held up.

I'm sure I have a shaft seal problem because I can actually wiggle the pully and hear freon leaking as I do.

As I see it I have the following options in order of cost:

1. Try the rebuild procedure
2. Pick up a re-manufatured compressor on Ebay
3. Purchase a new replacement Sanden 507

Any thoughts?

Also did you replace your receiver/drier at the same time?

Thanks for any insight.

[robhamster]

I replaced my Nippo 5 years ago with the Sanden and R134 and have never looked back. I have a cab so the AC works overtime when it is sunny and hot with that black blanket over my head and I get good cool air. I have not done the conversion yet on the lower bow tie vent, but will this summer just to add to the air flow. Also, I did replace the dryer. the dryer should be changed anytime you expose the system to the atmosphere. There is a different oil needed for the R134 system, but if you buy a Sanden it comes with that oil.

I had the system checked for leaks a few months after I did the conversion because it seemed I had lost some R134 and they could find no leaks at any joint or at the compressor. The guy said that the hoses tend to hold R12 molecules better than R134 molecules. I guess there is some diffusion of R134 through the hoses over time. I now recharge the system in May and have to do it again in August if I drive the car every day, which I tend to do. Each time I recharge it takes about 1/2 to 3/4 of a can and I have great cool air again.

Good luck

[Barrpete]

Had the same dilemma a year ago and posed the same question.

The most helpful answer was from Kuehl:

"Success in "rebuilding" the Nippondenso will depend upon:
The condition of the pistons, bores and swash plate. Since the Nippon does not have rings on the pistons or sleeves in the bores, what you see is what you get; if you have scratches or excessive wear it is not worth "rebuilding" (or what we really mean "repairing").

You are limited in your repair to: replacing the nose seal assembly and case o-rings and maybe the shaft bearing and swash plate bearings.

If the nose seal is throwing oil you have to consider if this is because:
A) The system had a "hic-cup"; meaning a one time high side overpressure situation that allowed oil and gas to vent out,
B) The system is running at excessively high pressures for various reasons,
C) The shaft-seal contact area or surface is rusted or pitted, or the carbon bearing is shot

Figure you will spend, if you are equipped to rock & roll with a repair, at least 3 hours to remove, clean, disassemble, clean R&R subcomponents, re-assemble and replace the current unit.

If you are running a Nippon we would assume you have a 84-89 3.2 (or euro turbo). The Sanden will not simply "bolt on". The mounts are different so you will need an adapter plate, and the high side hose fitting for the stock Nippon is typically a 45 deg for non-turbo; you have to consider if hose will angle properly. A "new" Nippon without a clutch ranges usually ranges from $399-499.00 and with a clutch from $499 and up. Depending upon the condition of your clutch assembly and bearing in the pulley, you may or maynot have to replace the clutch. And you will need a new drier for safe measure, a few o-rings for the hose connections and about 6 oz of ac compressor oil (typically and ester works great for either R12 or R134a)."

In the end I couldn't be sure a rebuild would last & since I didn't want to be constantly fixing/replacing some component I opted to replace compressor (Sanden), evap, fr condensor, hoses, added a procooler & switched to 134a. It will be 107 in Tucson today & my AC works just fine.

Regarding the R/D, if the system has been leaking you should probably replace it.

[DonMo]

Or you can be a smart ebay shopper and buy a 507 for $125 and get your local hydraulic shop to put you a 45 deg. fitting on for $10, fab up your own adapter for $10 of metal, buy a new drier for $30, draw a vacuum and put 134a or one of the other unmentionables (Freeze 12) in it for far less. The Nippondenso is a great compressor it just is a little more of a challenge for us DIY to rebuild.

[scottb]

For those who haven't seen it, here's the tech article on rebuilding the Nippondenso compressor. It seems pretty DIY-able. I'd give it a go if your compressor was in otherwise good shape and working well before it crapped out.

Scott

[scottb]

Originally posted by Barrpete
Regarding the R/D, if the system has been leaking you should probably replace it.

You might consider adding a ProCooler if you're going to replace the R/D. It helped my system.

[kepperly]

The only glitch I had rebuilding was finding a internal snap ring
plier with long enough points to reach the front snap ring that holds the clutch on. Otherwise its less than $40.00 bucks for parts.

Keith Epperly
87 slant nose turbo look carrera cabriolet

[mthomas58]

Originally Posted by kilodawg

I have an '84 with a Nippondenso compressor and I'm still running R12

I'm debating starting in on compressor rebuild. I am curious if anybody has used the tech article to perform the shaft seal R&R, what your results were and how well it held up.

I'm sure I have a shaft seal problem because I can actually wiggle the pully and hear freon leaking as I do.

As I see it I have the following options in order of cost:

1. Try the rebuild procedure
2. Pick up a re-manufatured compressor on Ebay
3. Purchase a new replacement Sanden 507

Any thoughts?

Also did you replace your receiver/drier at the same time?

Thanks for any insight.

I'm contemplating the same. What did you decide to do?

I'll be replacing my evap, front condenser, adding an underbelly condenser & Procooler and fabricating all new barrier hoses this winter. At that point, every component in my system will be new except for the compressor. I'm also considering converting to 134a so the entire project will be DIY friendly (except for evacuating the old R-12). Since 134a runs at a higher pressure, putting addl strain on a 20 yr old Nippo seems ill advised. I'll probably go ahead and replace with a Sanden 507.

[kilodawg]

I haven't pulled the trigger yet but I tend to listen to my wrench and he'd prefer I stick with a new Nippondenso along with a new dryer. He isn't a big fan of the Sanden. I'm not looking for ultimate AC since it isn't a daily driver.

[kepperly]

If you pay attention to the procooler info, you will find you actually use less freon and at lower pressures.

Keith Epperly
87 slant nose turbo look carrera cabriolet

[kepperly]

forgot to mention, basic repair for a nippondenso is to replace o-rings and the front carbon bearing/seal . Besides cleaning out the old gunk thats about it!!

Keith Epperly
87 slant nose turbo look carrera cabriolet

[kilodawg]

Keith,

You have me thinking about trying the rebuild again first. My symptoms are a small leak at the shaft seal I presume. The compressor and clutch run fine but you can hear the leak at times when the car is off and you can actually make it stop just by pushing in with hand pressure on the clutch.

Does this sound toy you like a candidate for a rebuild?

[kepperly]

Sounds like you just saved about $300.00, I take my advisory fee in good old
93 octane! Yes Thats all I did. The ONLY ISSUE IS the front carbon seal and getting it clean internally. Before you remount add about 2-3 Oz's of your flavor of oil right into the ports, much easier whe the compressor is off car.
Another secret, when you are tightening all the fittings that have o-rings, don't turn the o-ring just allow them to compress, not twist.

Keith Epperly
87 slant nose turbo look carrera cabriolet

[mthomas58]

Ran across this detailed compressor rebuild procedure while surfing this AM and thought I'd post it here:

http://homepage.ntlworld.com/simon.stirley/htmlman/acpump.html

[DRACO A5OG]

Hey Keith,

My Compressor started to make a rattling noise while AC is off, I suspect the Rotor Bearings. Can you post the link where you got your parts for the Denso Compressor?

TIA,

Jim

[JeremyD]

I can tell you that you'll have less parasitic draw from the Sanden than the nippondenso. My car has 993 cams which are right on the edge of motronic driveability - as in - when you take your foot off the accelerator the revs will drop to nothing - my steve wong chip catches it and keeps the motor running. When I was running the nippondenso - my car would occasionally stall because of parasitic drag - I do not have these issues with the Sanden.

- Just one man's experience.

[DRACO A5OG]

I agree with the Sanden Upgrade, but I want to try to fix the Denso before I have to evacuate the R12, replace the Dryer, evacuate the air and refill.

[84_Carrera]

FYI, I removed the AC from my 84, still have the compressor sitting on the shelf. Was going to eBay it someday, but if you need it, let me know.

[DRACO A5OG]

Pmed you Fred

[DRACO A5OG]

BTW, just found a local parts store that has the clutch rotor bearing for $35, is that too much?