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Discussion Starter #1 (Edited)
This car came to me with a dead A/C system and summer is approaching so it was time to bring the system back to life.

After reading several threads on this subject, I decided to rebuild the A/C compressor, replace pressure and temp switches and change out the expansion valve. My plan is to find any leaks, fix them and recharge with R12. As of this time, I'm not planning on converting over to R134a due to some of the feedbacks I've read.

You can purchase rebuilt Denso 10PA17C a/c compressors all day, usually over $200. I decided to change out the seals and the bearing on my unit and basically rebuild it myself. This has to be one of the easiest compressor to rebuild! Seriously, it took less than one hour to do the job. I spent more time dropping the unit out of the car and re-installing it.

Centurybob posted up a series of three videos on how to rebuild this exact compressor and they're extremely valuable. Once you watch the videos, you'll see how simple this process really is.

Compressor re-seal part I:

Compressor re-seal part II:

Clutch bearing r/r:

By far, the hardest part of this whole process is dropping and re-installing the a/c compressor. In my case, one of the allen head bolt was stuck on super tight and was a PITA to remove. See this thread for more info: http://www.benzworld.org/forums/w124-e-ce-d-td-class/1644786-rth-removing-c-compressor-bolt-hex.html This process took about two hours that I'll never get back :mad:

The next difficult process for me to re-install the unit back into the car. The bolts (#7 in the above linked PDF) kept wanting to fall out while you're under the car, holding the compressor up. At the same time, you need to pay attention to the new O rings that shouldn't be damaged during this process. So, be careful that you do everything slowly and carefully and have an extra pair of hands helping you out from above.

I wanted to have a super clean and shiny compressor housing but doing so would require extremely vigilance on the prevention of crap migration through the two ports. I kept the two ports plugged with my fingers while giving it a bath in the solvent tub but it was too much work.

Picture of the bolt that was destroyed during removal. I had a spare one.



The cost of the rebuild kit was $65, shipped. This included all seals and the clutch bearing and a tool for the shaft seal. Kit came from centuryautoair.com. Your contact person is Bob Steinmann, whose voice you hear on the Youtube videos. I've emailed him directly and he has been uber helpful.

My order list:

Part KT-10P17CN - NIPPONDENSO 10P17CN SEAL KIT ( MERCEDES) KT-10P17CN

Part SK-732N - NIPPONDENSO 10PA SERIES SHAFT SEAL KIT - SK-732N

Part BG403 - NIPPONDENSO 10PA15-10PA17-10PA20 BG403 (clutch bearing)

Part SPGM - SEAL PROTECTOR DENSO 10PA / GM LIP SEALS-SPGM (shaft seal tool)

Some pics that'll help you understand the scope of the project:

I made some room in the engine bay by moving the IGN coil and the air cleaner housing out of the way. The vacuum line for the brake booster was moved as well. Front of the vehicle was on ramps.

Front view:


side view:


Just follow the videos and take apart one section at a time, replace the O ring and put it back before taking apart the next section. This comp comes apart in three sections.

















Speed sensor on the back of the compressor:







Tools I used:



Removing the compressor requires the use of a 13mm socket and a ratchet. Unfortunately, it's a little tight in there so using this gear wrench/socket combo worked at treat.



Removing of the 20 year old three pin socket requires skinny fingers belonging to a Gorilla! Lucky for us, we can use these hose pliers to dot the same thing!





This is the refrigerant oil I used for the project. I didn't have a squirt bottle so used a syringe with a fat needle instead.





Clutch bearing: new left, old on the right (Koyo)







This is a picture of the shim that is used to gap the clutch accurately. It's basically a tiny washer.





Parts from AutoHausAZ:









To be continued.....
 

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Discussion Starter #2 (Edited)
continued...

It's easy to install new switches once the drier is out of the vehicle and on a bench:



Handy sheet that came with the reseal kit from centuryautoair.com. According to Bob, those two O rings will be left over from this project. One of those O ring comes with the shaft seal kit (bought separately) and the second one is not applicable to this compressor.



Cans of R12 goodness and sealant can:



Well, that's about it. I hope this post inspires confidence in you to rebuild your a/c compressor. About the only specialized tool that I can think of is a hydraulic press for pressing out the clutch bearing. I think you can do the same thing using a decent size vise. Incidentally, my bearing was super smooth and spun freely for a long time but while I was in there, figured it was time.

This project is about cleanliness so think like a surgeon! The case needs to be cleaned so crap doesn't fall inside once you have it apart. Clean and clean often :thumbsup:

It may not be a bad idea to have on hand an extra allen bolt that I destroyed in the process of removing the comp. If not, you should be able to source it from your local hardware supplier. Be sure to apply a little bit of anti seize on the thread before re-installing. This is a steel bolt living inside an ALUM housing for 20+ years. Probably would be a good idea to squirt a penetrating fluid on this bolt for about a week just in case it's stuck in there.

Time to rebuild compressor: 45 min
Remove compressor: should take about half hour unless you have a frozen bolt and in that case, two hours!!
Install compressor: an hour with minor aggravation.

Let me know if you have any questions.

Cheers.
 

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Discussion Starter #5
Thanks for the kudos. It was time I contributed to this great forum.
 

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Discussion Starter #8
Bravo! hope I don't have to do this!
I don't know John, given the age of our cars have, it'll probably happen to you some day, sorry :D But, it's a very easy thing to do as you can see. If I can do it, anybody can do it.
 

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Awesome thread. My 92 400e is leaking freon around the front seal (dye on the back of the pulley and on the brake vents). It holds vacuum, so I'm assuming the leak happens when the system is charged and running. Any other tips for a newbie looking to reseal an r134?

Thanks,
Todd
 

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Well, I've completed the rebuild on my 400e. Some tips based on my experience:

1. Double check your parts when they arrive. My rebuild kit was missing one of the large o-rings.

2. If you need a syringe, you can find them at the local pharmacy. I purchased one specifically for giving medication orally. ~$1.30 at Sprawl-Mart.

3. Century recommends mineral oil for your o-rings, but you need PAG 46 for r134 systems.

4. Order additional o-rings for the ports on the compressor. I buggered one up (see next point) and had to buy a $10 kit locally to get one ring.

5. Bolt up the manifold before mounting the compressor. I mangled an o-ring doing this in reverse order.

6. I had dye in my system already. If you don't, I'd add it to the compressor with the oil or charge with freon that includes dye (one can of freon with dye is fine. Fill takes ~2). Dye was critical to identifying my leak (front seal).

7. Correct torque for the compressor is 23 ft-lbs, not inch-lbs. This is corrected in the comments on the 2nd video.

I'm pulling vacuum now. Fingers crossed she fires up and is leak free.
 

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Discussion Starter #11
I'm keeping my fingers crossed for ya! Good job.
 

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alia176; This is a great thread with excellent photos, THX! for taking the time to do this.
I had to buy a new pump $287 and am now cleaning out the lines, flushing the system.
Didn't want to take a chance that mine wasn't rebuild-able.
 

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Great write-up! I'll be doing compressor rebuild myself for the 87' 300TD.
 

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Discussion Starter #14
Good luck with it, it's a painless process!
 

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I'd make my wife *really* happy if I got the a/c in her red sedan working again. This has inspired me. Great info!
 

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Correct torque for Head Bolts

7. Correct torque for the compressor is 23 ft-lbs, not inch-lbs. This is corrected in the comments on the 2nd video.
.
I torqued mine to 23 Nm which is about 17 ft lbs, which is what I found to be the common torque spec for a Denso 10PA17 compressor. And even that seemed like it was going to strip and it was nerve racking until it finally clicked. It sealed fine and i have no leaks. Do it in steps and in a star pattern. 23 ft lbs is a little too much and you run the risk of cracking the head or striping the threads. 23Nm is also the torque spec for the compressor mounting bolts and the allen bolt for the suction/delivery manifold.
 

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It's easy to install new switches once the drier is out of the vehicle and on a bench:



Handy sheet that came with the reseal kit from centuryautoair.com. According to Bob, those two O rings will be left over from this project. One of those O ring comes with the shaft seal kit (bought separately) and the second one is not applicable to this compressor.



Cans of R12 goodness and sealant can:



Well, that's about it. I hope this post inspires confidence in you to rebuild your a/c compressor. About the only specialized tool that I can think of is a hydraulic press for pressing out the clutch bearing. I think you can do the same thing using a decent size vise. Incidentally, my bearing was super smooth and spun freely for a long time but while I was in there, figured it was time.

This project is about cleanliness so think like a surgeon! The case needs to be cleaned so crap doesn't fall inside once you have it apart. Clean and clean often :thumbsup:

It may not be a bad idea to have on hand an extra allen bolt that I destroyed in the process of removing the comp. If not, you should be able to source it from your local hardware supplier. Be sure to apply a little bit of anti seize on the thread before re-installing. This is a steel bolt living inside an ALUM housing for 20+ years. Probably would be a good idea to squirt a penetrating fluid on this bolt for about a week just in case it's stuck in there.

Time to rebuild compressor: 45 min
Remove compressor: should take about half hour unless you have a frozen bolt and in that case, two hours!!
Install compressor: an hour with minor aggravation.

Let me know if you have any questions.

Cheers.
I assume when you rebuild the compressor, you automatically replace the dryer? Also How do you know the compressor has to be rebuilt as oppose if it was AC Relay malfunction?
 

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Yes, when you open the AC system, you need to replace the drier.

As a quick check, does the compressor turn freely and smoothly with engine off? If yes, you need to do some pressure readings with a manifold gauge set with AC off and AC on then post those readings here.


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