Compressor Clutch Bearing Replacement.

[DMCJosh85]

I've only had my Sanden SD7H15 for 2 years now but unfortunately the compressor clutch bearing is starting to go and is letting me know this with really awful squealing until it has warmed up. Its Winter now so I just removed the belt but im starting to do my research on how I will accomplish this repair and the first thing on my mind is wonderinf if anyone can vouch for the fact that it can be done on an installed compressor? I'd really rather not has to go through all the AC refrigerant process again over this just to remove it from the car, but when summertime comes-- Ill do anything for that cold air.

So, can anyone vouch for the ability to even do this on a compressor that is still installed onto the engine?

[Rich]

Link: Sanden SD Service Manual (https://www.sanden.com/objects/Sanden%20SD%20Service%20Manual.pdf)

Have a look at this manual before you think about tearing into the clutch.

Clutch disassembly may be possible without opening the refrigerant system. Check out the removal tools needed. Reassembly may be a different matter, esp for getting the rotor pulley back on. Then there's the issue of any parts you may need to replace. No direct experience here so no firm answer from me.

It could be a bad bearing as you say or it could be a bad clutch spring or other component. If the clutch doesn't fully release when it should you'll get a horrible noise (with compressor "off"). Is this when you hear the noise? Or when compressor is engaged?

Sanden USA may have a service desk to help you out on this. Sounds like a problem that could happen on any Sanden application, not only on this car.

[DMCJosh85]

With the belt off I gave the clutch disc a spin by hand and it just wants to stop, whereas when brand new that thing kept on spinning for awhile. I'm certain that I am right but I appreciate the advice and will look into your suggestion on that, thanks for the service manual link Rich.

Looking at this video is what shows me that tooling that requires perhaps more depth than what I'll get away with with the compressor installed. But perhaps ill end up finding some compatible bearing pulling tools that might allow for the job.

https://www.youtube.com/watch?v=5m5jtdX7_I0&t=182s

[David T]

With the belt off I gave the clutch disc a spin by hand and it just wants to stop, whereas when brand new that thing kept on spinning for awhile. I'm certain that I am right but I appreciate the advice and will look into your suggestion on that, thanks for the service manual link Rich.

Looking at this video is what shows me that tooling that requires perhaps more depth than what I'll get away with with the compressor installed. But perhaps ill end up finding some compatible bearing pulling tools that might allow for the job.

https://www.youtube.com/watch?v=5m5jtdX7_I0&t=182s

The bearing *can* be replaced without disconnecting the hoses. Even with the special tools it is a pain-in-the-neck job, much easier "on the bench". Price up a replacement compressor, a new bearing, and the special tools. It might just be easier to replace the compressor and not all that much more expensive. Or maybe send the compressor out to have it done to a place like Classic Air in Florida. The bearings you get today are junk. Hard to get any that aren't made in China and if you can find one they are VERY expensive. China has just about cornered the market and driven most of the bearing manufacturers to either go out of business or have them made for them in China. Very sad. BTW, if you don't use the "correct" tools for the job you can end up damaging the compressor and the new bearing.

[DMC-81]

With the belt off I gave the clutch disc a spin by hand and it just wants to stop, whereas when brand new that thing kept on spinning for awhile. I'm certain that I am right but I appreciate the advice and will look into your suggestion on that, thanks for the service manual link Rich.

Looking at this video is what shows me that tooling that requires perhaps more depth than what I'll get away with with the compressor installed. But perhaps ill end up finding some compatible bearing pulling tools that might allow for the job.

https://www.youtube.com/watch?v=5m5jtdX7_I0&t=182s

That video is a good one to reference. The bearing is lightly pressed into the belt pulley that he removed with the 3 jaw puller. Once you get that pulley off, all you have to do is press out the old bearing from the pulley and press in the new one. Very straightforward IMO. With some assistance you can unbolt the compressor from its mounting tilt it up enough to pull off the pulley, without having evacuate the system and remove the compressor from the car. It depends on your comfort level.
Get a quality bearing. I prefer Nachi and NSK for example.

Here is my AC system refurb if it helps any, especially on tools required and reassembly. I completely rebuilt the compressor and it is still going strong after 5 years.:
https://dmctalk.org/showthread.php?15632-Refurbing-a-Very-Early-A-C-System/page5

I think I replaced the bearing in mine, but I'll need to check my records.

Also, when you are finished, check how tight your belts are. Getting them too tight can cause premature bearing failure, both on AC compressor and alternator.

[DMCJosh85]

Thanks for all the information and suggestions. I tracked down the following bearing for the compressor, and what do you know? its an NSK https://www.amazon.com/dp/B007WDXWXK/?coliid=I3OC3ZHKK9S4DZ&colid=1Z7XWR9IV6DN&psc=1&ref_=lv_ov_lig_dp_it

I'm going to give this a try in the near future and I'll attempt to not disconnect the hoses. When I do ill report back how it all went. Thanks again everybody.

[DMC-81]

Thanks for all the information and suggestions. I tracked down the following bearing for the compressor, and what do you know? its an NSK https://www.amazon.com/dp/B007WDXWXK/?coliid=I3OC3ZHKK9S4DZ&colid=1Z7XWR9IV6DN&psc=1&ref_=lv_ov_lig_dp_it

I'm going to give this a try in the near future and I'll attempt to not disconnect the hoses. When I do ill report back how it all went. Thanks again everybody.

Great. That looks like the right one. Good luck with the job.

[Ron]

$.02
When you drive the bearing back on, use a tool that pushes the inner race (not the outer, as in the vid).

[DMCJosh85]

I finally got around to starting this job on my Sanden SD7H15 . It was obvious that room wasn't going to be possible in the installed position, however after removing the 6 holding bolts I propped it with some padding underneath and was able to work just fine. I reached a work stoppage for now until I use a Dremel to carefully shave off the staking that overwhelmingly secure the bearing to the clutch pulley. Cant say I was expecting to see this... Sanden really doesn't want that bearing out.

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[Rich]

....I reached a work stoppage for now until I use a Dremel to carefully shave off the staking that overwhelmingly secure the bearing to the clutch pulley. Can't say I was expecting to see this... Sanden really doesn't want that bearing out.

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Your unexpected finding, the staked-in-place clutch/pulley bearing, might be because your compressor wasn't really made by Sanden?

Hints:
- It died after just 2 years.
- The label on your compressor isn't "Sanden green" color. (but some of the fakes also have a green label)
- First glance at labels shows other non-Sanden design hints. See link below.
- It looks like Sanden really *does* want that bearing out. If it's a Sanden unit the bearing is held in by a snap ring on the other/front side of the pulley as seen in the diagram in Section 8.0 of the linked SD Service Manual in Post #2.
- Post #5 says the bearing presses out easily, consistent with the snap ring design.



Link to announcement of Sanden compressor anti-counterfeiting measures (http://www.sanden.com.sg/opencms/opencms/sites/default/Sanden/modules/news/news_0006.html) for SD5/7 units from 2011 has more details about their 2nd gen label design.

Be aware that not all "NSK" replacement bearings that are sold online were really made by NSK (https://www.nskeurope.com/en/news-media/news-search/2020-press/how-to-identify-and-avoid-buying-fake-nsk-bearings.html), either. Even the ones that have the NSK letters on them. Sorry.

[David T]

Could also be that the bearing was already replaced and that is why it got staked in. If it was replaced it may have been replaced by a cheap substitute and that's why it failed again. I have seen so many bearings fail, this didn't used to be a problem but with all of the junk on the market today it is a common occurrence now. I also see many bearings that have NO lubrication in them even though they are brand new. I always try to inject some oil or grease now so the bearing has *some* chance at a long life. As Rich says, they even counterfeit the packaging. Your best chance is to find a NOS bearing if you can.

[Henrik]

Your unexpected finding, the staked-in-place clutch/pulley bearing, might be because your compressor wasn't really made by Sanden?

- It looks like Sanden really *does* want that bearing out. If it's a Sanden unit the bearing is held in by a snap ring on the other/front side of the pulley as seen in the diagram in Section 8.0 of the linked SD Service Manual in Post #2.
- Post #5 says the bearing presses out easily, consistent with the snap ring design.


The Service Manual does not tell you to try to remove the rotor pulley bearing from the rotor pulley. It is only supposed to be removed as an assembly. The purpose of the snap ring is to hold the rotor pulley assembly onto the nose of the compressor.

[Rich]

The Service Manual does not tell you to try to remove the rotor pulley bearing from the rotor pulley. It is only supposed to be removed as an assembly. The purpose of the snap ring is to hold the rotor pulley assembly onto the nose of the compressor.

Agreeing, the pulley and its bearing do get pulled as an assembly as per the manual as well as the posted video.

Also agreeing, the manual doesn't tell you to pull the bearing out of the pulley. The manual also doesn't tell you not to do this. So it's not clear what one is supposed to do if the bearing fails, which is a failure mode listed in the guide Sec. 7.5.2.

Post #5 in this thread says removal of the bearing from the pulley is easily done, presumably from the front of the pulley as indicated in the exploded parts diagram in Section 8.0 of the guide.

From Post #5: "The bearing is lightly pressed into the belt pulley that he removed with the 3 jaw puller.
Once you get that pulley off, all you have to do is press out the old bearing from the pulley and press in the new one. Very straightforward IMO."

I haven't torn one of these down so I can't directly confirm any of this. Only reporting what I see in the Sanden guide and in the forum.

If the bearing failed and the owner can't reliably replace it within the pulley then the options are either a replacement pulley-bearing assembly or a replacement compressor.

[Henrik]

Agreeing, the pulley and its bearing do get pulled as an assembly as per the manual as well as the posted video.

Also agreeing, the manual doesn't tell you to pull the bearing out of the pulley. The manual also doesn't tell you not to do this. So it's not clear what one is supposed to do if the bearing fails, which is a failure mode listed in the guide Sec. 7.5.2.

Post #5 in this thread says removal of the bearing from the pulley is easily done, presumably from the front of the pulley as indicated in the exploded parts diagram in Section 8.0 of the guide.

From Post #5: "The bearing is lightly pressed into the belt pulley that he removed with the 3 jaw puller.
Once you get that pulley off, all you have to do is press out the old bearing from the pulley and press in the new one. Very straightforward IMO."

I haven't torn one of these down so I can't directly confirm any of this. Only reporting what I see in the Sanden guide and in the forum.

If the bearing failed and the owner can't reliably replace it within the pulley then the options are either a replacement pulley-bearing assembly or a replacement compressor.

Not to sound high and mighty but I have a past as a compressor engineer and lab manager from Sanden in Wylie, TX where the SD7H15 among other models are designed, tested and manufactured and I co-authored many parts of that service manual in the 90s, primarily the sections that deal with R134a conversions and flushing procedures etc. If you watch the youtube video again you can see that they guy never attempts to remove the rotor pulley bearing from the rotor pulley, and if you look at Section 8.0 of the Service Manual you will see that item 8 says Pulley & Bearing Assembly ie the bearing is not separated from the pulley even in that exploded view. Yes, clutch bearing is stated as a possible source of "unusual noise", not necessarily a failure mode, in 7.5.2 but a complete bearing failure is very uncommon and if it does happen, you should just get the complete rotor assembly if you can find it. Believe me, I have seen hundreds and hundreds of these being tested to their absolute limit in test benches, and just as many torn down for post-test inspection. The wobble plate compressor, such as the SD5 and SD7, is generally very durable but they do have several "weak links" such as the centering ball, the pistons, the piston rods, the suction/discharge valves, the lip seal etc and one of them will fail waaaay before the rotor bearing even starts to chirp.

[DMC-81]

Interesting. The staked bearing must have been done on later compressor versions. I have two versions of pulleys; an original black pulley assembly from a 1981 date coded DeLorean compressor, and a clear zinc pulley. Both use the snap ring fastening method.

Black:
https://dmctalk.org/attachment.php?attachmentid=69431&d=1676818616

Clear zinc:
https://dmctalk.org/attachment.php?attachmentid=57670&d=1533337513

[DMCJosh85]

In the end I was able to complete my objective without having to deplete my R-134a charge. This was done by removing the 6 bolts that hold the compressor to its mount and placing some rags as a cushion underneath across where I flexed it to lay at so I could do my work. The only special tools needed where...

1: 6-inch, 3-jaw puller: https://www.amazon.com/dp/B08G8SQ7FJ?psc=1&ref=ppx_yo2ov_dt_b_product_details
2: Clutch holder: https://www.amazon.com/dp/B004KEFCPU?psc=1&ref=ppx_yo2ov_dt_b_product_details
3: Feeler Gauge: https://www.amazon.com/dp/B06XHXJG31?psc=1&ref=ppx_yo2ov_dt_b_product_details

After grinding out the staking with a dremel as found on other automotive website, I later discovered that I could get a replacement pulley and bearing assembly for slightly more than what a NSK branded replacement bearing was alone. I found this at https://www.ebay.com/itm/253926488880

It seemed every bit identical to the original and even had yet another staked bearing. Maybe its cheaper to stake a bearing in place then machine the groove for a snap ring on both sides of the bearing. Anyway I did all the work quite easily from the compressor sitting on a pad, put it all back together and gave it a test with success.

For what its worth the Sanden model 4708 was purchased here originally: https://www.acparts.com/product/new-original-sanden-compressor-4708/ - I have no reason to believe that I have a forgery in any capacity, bearings go bad all the time, or to close on a befitting quote...

"Screws fall out all the time. The world is an imperfect place." - John Bender

[Rich]

Good solution. Thanks for wrapping up the happy ending.

Your new pulley+bearing assy should last a lot longer than the first one did according to Henrik.

Stay cool.