*** This is split into posts #1 and #2 due to image quantity limits (12 max per post) ***

I've got the Sanden system, it was R12 and needed a recharge like 10 years ago, at the time I converted to R134 by an indy shop and that also leaked. So I started using R152a based on the excellent information here on the forum. But that also leaked over the course of a year. I've grown tired of recharging it so I've finally looked deeper. Looking with UV dye, I found leaks at the compressor shaft seal and at the connection going into the condenser. I've solvent purged as best I can doing the lines that don't connect to the evap/expansion , the condenser. Basically all the stuff in the bay except the compressor of course. New receiver drier from RA (like $8!). I blew compressed air through the evaporator and expansion valve and saw no oil come through.

This post focuses on the compressor. Here's the leak, clutch face removed at this point.




There's lack of reliable information for the exact SD-575 compressor but here's what I've found. I'm replacing the pully bearing (you could prob just buy a new 5.25" double vee clutch, but I wasn't sure how universal they are. I'll also replace the shaft bearing, the shaft seal, and the cover gasket (squared o-ring). You could try to use a replacement compressor although the models out there seem to be SD508 series and ubiquitous. I didn't want to do that, mostly because I didn't want to get into custom lines/fittings and all of the other questions it raises. So more certainty but also much more time working. I also like that it's the original compressor going back in.

This isn't a step by step tutorial, it's organized by the part you are installing. For a general overview, there are a couple of videos for Sanden compressors sort of like this one but the seal is different. The basics of removing the clutch in video 1 and opening up the front cover in video 2 are directly applicable:

Clutch

Seal

Some Tips and Tricks

The videos give you enough to know what to do and the photos throughout should dispel misgivings about disassembly. Take pictures even when you think you don't need one.

Heat and Cold: I drove out the bearings with various sockets, standard stuff, no torch. For reinstalling, I heated the bore with propane, not glowing red or anything that would compromise the material, change heat treated properties. I also froze the bearings. You need to act quickly reinserting and the freeze helps especially with the initial insertion. But the bearing heats back up quickly with the hot bore to get a good alignment and first whack right away. Use a dead blow hammer and a piece of wood to protect at first, an appropriate socket after that and ***always drive against the outer race when installing bearings***.

The shaft bearing will arrive greased up but it is an internal part, exposed to the Ester oil. You must clean it entirely and relube with Ester. I used brake non-chlorinated cleaner and an ultrasonic cleaner and it barely made a dent. Simple green full strength and a toothbrush was much quicker. *Very light* compressed air after that. Don't spin the 'dry' bearing with the air.

The pulley bearing is sealed and you should just install it.

Install the bolts for the clutch puller enough to fully thread in but don't bottom them out, this avoids damaging the compressor's front cover.

There are a bunch of photos at the end in no particular order, these are good for reference if you have forgotten how something fits. Not comprehensive though!

Tools
- Circlip pliers, good ones. So many circlips! I have a terrible pair and made it work, but the right tool would be a pleasure.

- OEMTOOLS A/C Compressor Clutch Hub Removal / Installation Kit 57150, rent at Autozone for a $105 deposit or buy on Amazon for $25.

- If you're pulling the JH1112 bearing then I found the HF bearing hammer pull did the trick, I happened to already have it.
https://www.harborfreight.com/slide-...ece-62601.html

- If you're using R152a (and you should! it's cheap and easy to charge) then make sure to use Ester oil.

- I did NOT need this to hold the clutch, I just used an impact wrench and the shaft nut came right off, almost too easily.


I also did not need a seal protector.


Here are the exact part numbers I am using. I'd give you links to the parts but they just disappear from eBay. So just google the titles as I've provided them

The Exact Parts That Fit the Sanden SD-575 Compressor

Clutch pulley bearing (mine was singing even though I did my best to repack it)
Koyo 83A694CS30 35mm ID x 55mm OD x 20mm


Shaft main bearing
NSK JH1112 Torrington Heavy Needle Bearing
This felt a bit rough so replacing it.



Gasket kit including the front cover square o-ring and the oil fill/drain plug o-ring
Santech MK2143
On eBay these claim to be compatible with SD505 / SD507 / SD508 / SD510 / SD5H13 compressors. I can confirm that the cover o-ring is the correct part and it measures just under 110mm ID x 1.5mmwide and 1.5mm tall. The old one had compressed to 1.0mm when I removed it. I am only removing the front cover of the compressor (at least for now) as the pistons and performance seemed fine so I cannot confirm that the other gaskets fit this model, they might.




Compressor shaft seal
AC Compressor Shaft Seal Kit Fits SD505/ SD507/ TR70/ TR90/ TR105
The package the new seal parts arrived in was labeled " April 2021 SS0831"
The shaft seal is three parts: the "ceramic carbon" seal, a sold steel plug with an o-ring, and a felt ring to absorb leaks. It's held in by circlip at the front of the shaft but you do need to remove the front cover to take out the seal because otherwise the shaft is in your way. . Below is my old seal and then a photo of the new part from the eBay listing.

Installing the seal for this compressor is completely different than the video indicates. It is a rigid piece that absolutely will not stretch and there is no need to "pre stretch" it to got over the shaft. You do not need "seal protector cover" to insert the shaft into the seal, there is very little resistance because the front of the seal is apparently the important part. The seal is keyed to the rotating shaft an so rotates with it. It is spring loaded and its front surface rotates against the raised section of the steel plug that is stacked just ahead of it. That steel plug has the o-ring which seals inside the shaft-way/nose of the compressor cover. See the photo at the very end that shows the stack order and the front cover.

I chose to install the stack into the front cover with the cover removed. With the shaft removed from the cover, drop the seal in to land on the bearing, there is room as the seal's circumference is smaller than the bore's diameter. Lube it and the plug's o-ring and raised segment with Ester, place it in the bore. I tapped it in lightly with a 14mm deep socket.
Next insert the shaft from the inside taking care to line up the spring cage's flats with the corresponding areas on the shaft (it's the rubber like ring that stays on the shaft).
Rotate the shaft so it seats into the cage flats, do this by rotating and pressing lightly, you might feel it "notch in, you might not, but you should be able to seat the shaft fully onto the face to the thrust bearings/cover.
Hold everything together and set the front cover/shaft assembly with the nose up. The long tube can hang over the edge of your work surface.
Tap the o-ringed plug deeper into the nose bore and install the circlip to hold it all in...you are compressing the seal's spring as you do this.

 

*** Part 2 ***


Details for the Compressor Nerds

Clean up the clutch surfaces with some green scotchbrite. Here's a before and after (you can still see the 10 mm bolts from the clutch puller in the plate). Still some spalling but it's fine and was working well beforehand.


Here are some photos of the compressor I am refreshing. Note how deep the back cover is and that it uses the "block" type connection that has both suction and discharge in the same fitting, bolted down together, sealed with o-rings. It seems like the aftermarket units that are "compatible" are 508 series and have a very shallow back cover. Also, I happen to have the clutch puller installed in the right had photo (you can rent this from Autozone, totally worth having if you are re-using the clutch).



And here is a close of the placard:



The label details are:
SD-575
Model 9165

which you would think would be helpful, but not really. The key bit is that it is a Sanden 507 series and the only real clue is the casting mark underneath the unit.

B507 S3


Just a Bunch of Photos

Here are some random shots in a somewhat logical order of disassembly. The special suction/discharge fitting for this series of abandoned compressors. There are channels for o-rings in the compressor, not shown.

Pulling the double vee was easy.



Looking down at the swash plate, first photo. You can see the ball and socket joint at the center. Then the driving surface with the shim plate and shaft
as mounted to the front cover. The tube is press fit into a channel in the front cover.
The hole inside the front cover between the bearing and tube (3rd photo below) is the entry/exit to the channel that is connected to the long tube.
That interfaces to the rear of the swash chamber and connects to the pump (very last photo at the bottom in the next series). Not sure if it's exposed to the high or the low side.



The stack order of the spring loaded seal, o-ring plug, and circlip. The felt absorbent ring and brass retainer is tapped in after that (not shown).
A small peek into the swash chamber showing the underside of the pistons and some pooled UV style Ester oil. The fill/drain plug threads are visible near
the tip of the flashlight.

 

Very cool. I think I have the same issue. I reinstalled by AC with new dryer/hoses/etc and sealed it up. Charge it and it leaks down within a few days. I suspect my compressor is leaking but haven't done the UV leak check stuff yet. Its getting to be summer so I may tackle this. I have a different compressor (SA factory) Denso I think. Anyway, I'm sure a lot of what you did here would apply. Thanks.