Yet Another Syncro Vibration Tale

[Black'n'White]

I've been chasing a vibration on an '87 Syncro for the past several weeks, thinking it was the driveshaft. Today, I removed the driveshaft and for the first time went for a ride. The vibration was still there. It's only at 35 MPH, and shows itself most strongly by a buzzing low in the passenger side door. I can also feel it in the steering wheel. It vibrates both with the clutch engaged and accelerating/decelerating, and when coasting with the clutch pushed in. Above or below 35MPH, no vibration.

I've had the tires/wheels balanced, twice.

I jacked the front end off the ground and checked for play by holding each front wheel at 12&6 o'clock and 9&3 o'clock and rocking back and forth and in and out. None detected.

Wheel bearings, shocks, and CV joints are all new within the last 500 miles. Small Car big brake kit installed at the same time.

New Powerflex bushings on the transaxle mounts and all three front diff mounts installed (33 ft. lb. torque) in the past couple weeks. It vibrated before the change, and after. Ran the Van Cafe alignment procedure twice; still vibrates.

I've tried using shims to better align the transaxle output shaft and front differential input shaft angles; still vibrates.

I've searched this forum and read 'till my eyes bleed, and I don't know what to try next. Any ideas?
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'87 Syncro/Westy Homebrew
Whatever it takes...

[Kombi///M3]

How’s your swaybar bushings and endlink?

[Black'n'White]

New within the last 500 miles, along with new upper and lower ball joints and tie rod ends.

However, all of this work was done by a mechanic with which there have been numerous issues. Any instructions on checking his work?
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'87 Syncro/Westy Homebrew
Whatever it takes...

[Black'n'White]

I should also mention this is a Subaru Frankenmotor conversion (2.5 bottom end with 2.2 heads) using an RJES bellhousing.

Anything else that might be important?
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'87 Syncro/Westy Homebrew
Whatever it takes...

[Sodo]

Exchange the front/rear passenger side wheels? Then they rotate the same direction just different location.
Just an idea....
Got mud tires? Are they “cupping”?
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'90 Westy EJ25, NEW oil rings (!) 2Peloquins, 3knobs, SyncroShop pressure-oiled pinion-bearing & GT mainshaft, filtered, cooled gearbox.
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered original gearbox
....KTMs, GasGas, SPOT mtb

[Black'n'White]

Rotating tires is easy enough to do, and if it changes the vibration, it points to a tire balance problem. Thanks!

Tires are Michelin Defender, also with 500 miles.

Lots of changes all at once makes it difficult to tell which one is to blame, huh?
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'87 Syncro/Westy Homebrew
Whatever it takes...

[Sodo]

New highway tires? Not very likely.
From a friend who knows these things....
—>B/W's vibration is probably the front diff pinion brg or the VC brg
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'90 Westy EJ25, NEW oil rings (!) 2Peloquins, 3knobs, SyncroShop pressure-oiled pinion-bearing & GT mainshaft, filtered, cooled gearbox.
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered original gearbox
....KTMs, GasGas, SPOT mtb

[Syncro Jael]

Try running with the front diff mounts loose. Take it for a drive and see if the vibration ceases. When I changed to the powerflex bushings I noticed a slight vibration. But it has since disappeared.

Even if the CV joints are new, make sure they are assembled correctly. I have also been down that vibration path and thought it was the prop shaft. A costly learning experience.

It seems a Syncro doesn't like 35-40 mph.

You will eventually find the vibration and smile.

Cheers.
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1987 Syncro Westfalia Hightop - NAHT
Subaru EJ25 Forged Frankenmotor, Triple Knob.
Jael = (Mountain Goat)

[Black'n'White]

Yesterday I tried the easy things first. Remember, the drive shaft is removed during the following:

I swapped the wheels on the passenger side, and it still vibrates.

Then I swapped the wheels on the driver side, and it still vibrates.

Got out a magnetic test stand and a dial indicator and measured runout on both front wheels. One was +-0.010", the other +-0.005". Close enough for the girls I go with.

Loosened up the front diff mounts, all three, and went for a drive. Started on small, bumpy, twisty paved roads, got to a smooth state route, went a couple miles, then pulled over in a straight section, crawled under the van, and tightened the bushings. Still vibrated.

When I say "vibrate", I mean there's a rattle in the passenger door, more of a buzz, that kicks off at about 30MPH and disappears just shy of 40MPH. Then at about 55MPH I start feeling a shake in the steering wheel, which disappears by 60MPH, then comes back as speeds climb over 70MPH.

Can CVs be a cause of vibration? The ones on this van have about 500 miles on them, so they're far from worn out. But it's not beyond the pale to have one that is defective. I just don't want to go barking up the wrong tree if the likelihood of a bad CV is low.

When I got back, I pulled the boots inward off the CV joints on the driver side. I had to remove metal clamps to move the boots, and I noticed that the crimp fitting on the outer boots was hitting what I think is the dust boot on the lower ball joint. I replaced the metal clamps with made in USA zip ties, and added zip ties to the small end of the boots.

The boots are from Rockford.

Both CVs were well lubed with some kind of gray grease, with no signs of dirt or water contamination. I moved enough grease around to verify that "wide" spots on the outer ring were opposite "narrow" spots on the inner ring, as per http://moira.meccahosting.com/~a0008423/cv_clocking.htm

How important is it that the CVs are clocked? I'm not running any lift on this van, and Old Man Emu shocks are installed. The only thing installed in the interior at this point is the driver seat, so it's probably riding a bit higher than a GL or Westy.

I contacted the shop that did the CV install and was told that the CVs are Lobro made in Germany, but not 944. The inner CVs had the single ring/triple ring markings, the outer ones didn't. The single ring faced the drive shaft. I found the 944 Lobro CVs at RMW, and the description says that the markings on the CVs vary all over the map, and can't be used to reliably ID what is what. Is that common?

Would the 944 Lobro CVs be a worthwhile upgrade?

If so, should I just buy the CVs, or instead buy axle sets?

And are there different part numbers between the diff side CV and the wheel hub side CV? I couldn't tell from the VW ETKa:
https://nemigaparts.com/cat_spares/etka/volkswagen/vasy/59u/050000/

If I buy axle sets, are different "sizes" required between the front and rear?

Ron mentioned incorrect assembly of the CVs; can anyone point me to a place in the Bentley or a link that would educate me on proper CV assembly? I'd like to go through mine and verify they've been done correctly.

I also found a link that suggested removing all but the outer CV in an effort to eliminate the CVs as a cause of the vibration. The link didn't mention how to do that. Is this something worthwhile to do, and just what would be involved? A link to a procedure would be most helpful.

Thanks, folks, I really appreciate the insights you've shared. Sorry for all the questions, but it seems like there are many worms in this particular can.
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'87 Syncro/Westy Homebrew
Whatever it takes...

[Black'n'White]

[Sodo]

Wow you're really diggin' into it.
At this point my only suggestion is to retrieve that plastic wire-sheath thats rattling around in the bottom of your passenger front door.....

[Syncro Jael]

[Kombi///M3]

I remember my first cv overhauled, I didn’t pay attention on the
Orientation and ended up doing it twice. It wasn’t much of a vibration
but grinding and buckling knocking feeling & sound. As for the front CV’s
There’s a thin spacer in the inner cv and the Allen bolts are longer than the
rears. 50mm front and 48mm rear. Not sure if that matter.
I still think it’s somewhere in your bushings. Double check any worn bushing
Specially the anti swaybar.

[Black'n'White]

[Syncro Jael]

[Black'n'White]

[Black'n'White]

[Mikesarge]

I've got one for you-

My van has an OBDI EJ22

I thought I had a syncro vibe issue, turned out to be an intermittent misfire. it would show up at/just off of idle, and under certain constant load situations- usually around 45 mph (indicated) on level ground.

Took me forever to diagnose because I bought the van with a ton of issues, so i had no idea. Bad intake valve. Even on 3 cylinders it was a lot stronger than the 2.1 syncros I had driven before, and I've never owned a subaru, so I just assumed they were lumpy and weak at idle. Now it's smooth and doesn't vibrate at any speed.

Any codes?

[Black'n'White]

[Black'n'White]

Was talking to a friend about the vibrations yesterday, and he asked me how old the tires were. They're about three years old now, but only have 500 miles on 'em. He says they might be flat spotted, and I think he might be onto something there. Back in the days of nylon corded tires, it was common for a tire to flat spot, but it rounded out after a few miles of driving. Could these Michelin Defenders have developed a permanent flat spot?
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'87 Syncro/Westy Homebrew
Whatever it takes...