Accessory vibrations a SAD9s) day??? - The saga of Njordi

[Boerderij_Kabouter]

I am experiencing some aggressive front end vibration intermittently. It appears to worsen with load (A/C etc.). I just crawled under and took some video of the SADS couplers and would love to hear the squad's opinion. In my other thread looking at swapping over to R134a refrigerant, @man_btc noted he thought it could be the A/C compressor causing the issues. I think my inspection makes me lean toward his diagnosis.

Video of the SADS couplers:
https://youtube.com/shorts/uYSBEMU6C...6LoRxqb3dMca2t

Here is the engine running with A/C off:
https://youtube.com/shorts/PXnkwxMjz...SRo5MXDbbRzZtB

And A/C on:
https://youtube.com/shorts/xJEBUdnqY...F1Chbcu5qPrwo0

Honestly, it feels like it shakes a lot even when the AC is not turned on. But that could be from several things. I think the couplers look like they were replaced on and I doubt whoever did that took the shaft and had it balanced.

Questions:

1. Has this SADS already been upgraded so I can just replace the couplers? (the 1992 version original required a full SADS shaft assembly replacement)
2. Do you think the condition of these couplers is causing my vibration?
3. Does it make sense for a bad A/C compressor to cause this much vibration?

[Boerderij_Kabouter]

Well, the weekend did not leave much time for me to do projects, but I got the fan and shroud out of the front. Honestly, a total pain considering how easy the manual makes it seem. But I got them out without anything breaking. Fan and fluid coupler appear to be in fine shape.

[man_btc]

I am experiencing some aggressive front end vibration intermittently. It appears to worsen with load (A/C etc.). I just crawled under and took some video of the SADS couplers and would love to hear the squad's opinion. ...I think the couplers look like they were replaced on and I doubt whoever did that took the shaft and had it balanced.

Questions:

1. Has this SADS already been upgraded so I can just replace the couplers? (the 1992 version original required a full SADS shaft assembly replacement)
2. Do you think the condition of these couplers is causing my vibration?
3. Does it make sense for a bad A/C compressor to cause this much vibration?

The bushings on your couplers don't look obviously bad to me - cracked to the edge or missing chunks of rubber. Just a thought - there are rubber mounts on the front supports for the SADS shaft you may want to examine - maybe by shoving it up-down-left-right in the front rather than just turning it along its axis? I would imagine if one of them was cracked or loose, you'd get a vibration similar to a bad engine mount which would certainly get worse with an AC compressor load. The manual emphasizes that those supports remained aligned properly.

There are loads of SADS coupler replacement threads of course, since that's a common issue that never really required the shaft and couplers to be replaced as one. Some involve fitting (presumably longer-lasting) BMW couplers to replace the original type, which is what I'd seriously consider if I had to do it once more. I've replaced the SADS couplers twice while leaving the shaft in place on my '92 - once with 3rd-party metal couplers and the second with whatever (OEM? - fingers crossed) was on my donor, neither time monkeying with removing or balancing the shaft. I do always try my best to mark parts such that I reassemble them in their original positions relative to each other.

[Boerderij_Kabouter]

I just took a look at the accessory frame mounts and they look like they are in really good condition. Certainly not broken and the rubber still feels pliable when I press on it with my finger. Forward motor mounts also appear to be good, but the tranny mounts are plasticized. Might replace on those.

I figured "while I am in there" has fired up. I ordered a pair of the BMW couplers (part number 26111225624). I will try to document how that swap goes once they show up.

It feel unlikely that my vibration is from the SADS but I may as well get it freshened up while the rubber is starting to look old.

I think my vibrations are much more likely from the AC compressor, so I am replacing that and will document that swap over on my AC thread.

[Boerderij_Kabouter]

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Ended up taking the air intake box and the battery box out to get a better look. This will be a good opportunity for some deep cleaning too while I wait for parts to show up.

[Boerderij_Kabouter]

Just got the SADs out and found that two of the front bolts were completely loose and most of the inserts totally broken and shot. Inspection while the SADs was installed proved to be more difficult than it initially appeared.

To get the SADs out, I used a rachet strap to lift the accessory assembly up.

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The front bearing appears to be in perfect working order. So my next task is to fit up the BMW couplers and then make the decision to take this thing to get it balanced or not.

[Boerderij_Kabouter]

Couplers installed. I bought 3/8 steel uncoated brake line from NAPA and cut them to 30mm in length. This extends 2mm beyond the 28mm thickness of the BMW couplers and should extend into the countersinks in the shaft and couplers.

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I then reassembled the shaft using Orange threadlocker. Then marked each connections with paint pens.

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Next step is to take this bad boy to a local driveshaft shop and get it all balanced. Pretty easy project!

[man_btc]

Pretty easy project!

Between this and your other work, you're presenting a compressed-timeline of what most earlier Previa owners went through over 10 years or more. On the shoulders of giants and all that (I'm looking at you, Tim!)

Nothing about the cupholder latch yet? - that's surprising 😁

[Boerderij_Kabouter]

For sure! It is awesome to find this community and the resources that are available. I am hoping to get Njordi fully right and set to run for another decade or so. The next refresh will be even harder for part sourcing, so I am trying to address as much mechanical stuff now.

Oh, my cup holder is broken of course. But cosmetic stuff will get addressed once Njordi functions correctly. I am a mechanical engineer, so the primary beauty for me is in the machine and its smooth operation. Once it is running like new, then we can work on body work, seats, sound deadening, audio, etc.

[Previologist]

am a mechanical engineer, so

Ahhhhh-HAHHHH!! I knew something was amiss here, with you getting so much done in so little time with so little hand-wringing. Not fair.

[bjk]

Couplers installed. I bought 3/8 steel uncoated brake line from NAPA and cut them to 30mm in length. This extends 2mm beyond the 28mm thickness of the BMW couplers and should extend into the countersinks in the shaft and couplers.

Dang. Just finished cutting my bushings but didn't think about the 2mm extension. Better to know now than after I get the thing apart. Thanks!

[Boerderij_Kabouter]

I don't think it is really necessary. The countersink doesn't match and will not realistically bear any load.

[Boerderij_Kabouter]

Just got my first test drive done and can confirm that these couplers are running balanced and smooth.

Here is a video of my first start up, you can see the smooth operation compared to the crazy shaking I was experiencing before this latest round of projects.

https://www.youtube.com/watch?v=oy-V_9h1KUA

[Jonny]

Between this and your other work, you're presenting a compressed-timeline of what most earlier Previa owners went through over 10 years

Nothing about the cupholder latch yet? - that's surprising 😁

That's because he read the thread on that.
https://www.toyotavantech.com/forum/...p-latch-repair