Hi friends. I will like to have some advice about replacing the seals of my 1991 Nippondenso 10PA17C compressor. The system had been running with R-134 for at least 6 years. I have noticed an ~ 12oz./year leak, not detected by the electronic leak detector. I will be changing the system to R12. My plan is to remove the compressor, drain it and replace all the seals with new ones. I understand that I can get the tools at ACKITS for that job. I will flush the condenser, replace the filter/drier, replace all the O-rings, and fill it with R12. How difficult is to replace those seals for a DIY's? Is it true that the R-134 eventually damage the seals? Please advice on this subject. Thank you all.

Darrel
350SD 1991

It's not all that hard. I've done the front seal on the junkyard 10P15C currently in my '87 diesel wagon. Here's a link to a how-to article: http://www.pelicanparts.com/techarticles/911_Nippondenso_rebuild/911_Nippondenso_rebuild.htm The subject car is a Porsche, but it uses a Nippondenso 10P15c. I believe the shaft seal is identical between a 10P15C and 10P17C.

The only special tools required are snap ring pliers. As I recall you will need two different sizes. I just purchased an inexpensive package of four at my local auto store for about ten bucks.

It's not that hard a job - I pulled the compressor, replaced the shaft seal, reinstalled, vacuumed, and charged - all after work one evening. You're in for a bit more work - I didn't replace the case o-rings. Don't forget the four o-rings which seal the manifold to the compressor body. I've had these fail - they are exposed to the most extreme heat and pressure in the a/c system.

Oh, and don't forget to reset the clutch air gap when reassembling. You may want to purchase a kit of shims as well. I'm fortunate to have a really good local a/c supplier where I purchased both the front seal and shim kit for ~$25.

Good Luck,

- JimY

Thank you for your prompt and precise answer. The article is excellent. The only thing I am not clear is about the shims. Please explain in more detail if possible. Also, where can I get all the seals for the shaft and the case? Thank you again.

Darrel

Howdy -

You can probably buy the parts on the web at either http://www.ackits.com or http://www.acsource.com There is also an automotive bulletin board at http://www.aircondition.com Lots of helpful advice there, and other parts suppliers as well. For a local source, look in your yellow pages. There should (?) be an entry under automotive air conditioning: parts and service, or something similar.

OK, clutch air gap. Look at figure 3 on the website I referenced - click it for a big picture. The clutch drive plate is pulled against the pulley (which is driven by the serpentine belt) by the magnetic force of the coil, when energized. When the compressor is not running, the clutch drive plate has some clearance ("air gap")between the pulley. This gap is adjusted with spacers. One is shown in the picture - it's the little round thing that looks like a washer, just below the "clutch drive plate removed" text. The air gap is supposed to be 0.50mm. It increases over time as the clutch material on the back of the clutch drive plate wears. You adjust it by using shims of different thicknesses. I suggest you buy a package of these shims as part of reconditioning your compressor. Any supplier that has the shaft seal will also stock the shims.

Last point. Are you certain your car has a 10P17? I really thought all the diesels were only equipped with the 10P15C. Better make sure. I think the shaft seal and shims are the same, but I'd guess the o-rings for the compressor case are different.

- JimY

Thank you again Jim for your advice. I went to the local a/C supply and found everything. Yes the seal replacement will work on both the 10PA15 and the 10PA17. I double check and yes mine is a 10PA17C. I also have a supplement of the A/C service manual from MB that specifies that it is a 10PA17C. I need to go back because I forgot the shims, and I need the mineral oil. Maybe you can help me with another topic. I went to the Mercedes parts suppliers to get the driver's side window switch and they ordered the wrong one (passenger's side). Is there a place where I can get a software or a microfiche or a manual of the engine and chasis # parts for the 350SD-1991? If you know some information of where to get this it will be appreciated. It will be ideal if the serious Mercedes owner could get a copy of the software they have at the Mercedes parts place. Thank you again, I will get back when the job is done, although I plan to do it during the holydays.

Darrel.