Syncro Propshaft Alignment Problem

[Landsailer]

So my original propshaft died this summer. The internal bushing failed. When it came time to buy a new one, I got a sweet deal on a double cardon slip yoke shaft. Now, when it comes to lining up the flanges for install (I don't have a laser tool, but I am using a crude string method, yeah, I am kind of cheap, but it seems to be working), I am running into a problem. The trans flange is nearly square with the skid bars, meaning it's pointing almost dead ahead. Now, when it comes to the front, the flange on the diff is point down. Way down. And if I try to shim it up: 1. I run out of bolt on the two mounts on the back, 2. I can't shim it high enough to point straight back anyway because the coolant pipes are in the way. So, just wondering how everyone is maneuvering their front diff so that it doesn't point down. I haven't gotten around to looking at the front mounting bolt on the diff, and I guess it's possible that somebody decided it was a good idea to shim the front (therefore teeter-tottering the back down), but why? Anyway, looking for any help I can get. Thanks.

[IdahoDoug]

In your post you merely speak of wanting to align the flanges. You don't speak of having any issues with your new DC shaft. So, I think you should clarify if you are having an issue that needs correcting or if you are literally trying to align the flanges for its own sake.

Be advised, the DC shafts have different flange alignment needs, and their reason for being is to tolerate much greater running angles than a stock type shaft joint.

DougM
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[Landsailer]

I do want to align the flanges, but not for their own sake. The manufacturer of the shaft specified a certain angle parameter. I don't have that right now so I began trying to get the faces of the flanges parallel. I have the back flange pretty damn close to plum, or pointing directly forward if that makes more sense. The front flange is pointing down. The whole diff is pointing down. Just wondering if this was ever an issue for anyone else as even with a fancy laser tool, I don't see these flanges lining up in the situation I see.

And I ran the DC shaft after first install with no adjustment to anything on the van, and there was more vibration than the original busted driveline. So, just trying to line things up to get rid of it.

Hoping one of the gurus on here will drop one of those awesome samba techniques that work every time.

Thanks.

[IdahoDoug]

If a brand new DC shaft is vibrating, my absolute FIRST inclination would be to find a shop that has a jig to balance it. Do not assume a shop that does a lot of shafts can balance yours, because it is an unusual size and most will not, so bring the shaft to each shop in your small community (AK?). The hallmark of a DC shaft is to better tolerate not only angles, but DIFFERENT angles at the flanges (meaning one flange 3 degrees from straight, the other 5), so I think you are barking up the wrong tree. A shaft out of balance will feel unbelievably problematic.

For instance, you may have a great shaft that was balanced beautifully and it sat on a shelf somewhere for a long time. At some point, someone pulled the shaft's splined end off out of curiousity and put it back 90 degrees off. Or perhaps your shaft is used and someone did it. Or perhaps you did it to lube it before install. The ways to get a shaft out of balance are legion and the only way to correct it is to hand it to a professional and have them balance it. I recently paid $60 to have a Syncro shaft with brand new joints balanced. Took it from an undrivable vehicle, to literally smooth as glass.

So you are likely barking up the wrong tree if your flanges are even close but you are still getting vibes on a new DC type shaft.
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[ragnarhairybreeks]

don't have the flanges parallel, rather have them both pointing down an equal amount, but no more than 4 degrees. I think 2 degrees would be worth while shooting for.

No provision in the syncro set up for much adjustment for flange angles. Owners end up mucking around with mounts. One place to get a little adjustability on front diff is in the yoke that run over ands supports the rear for the diff. There is alittle up and down adjustment there, not much though. Leon IIRC, moved those holes to make the flange angle different.

alistair
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[IdahoDoug]

Also, do you have a clear knowledge of the front mount and its spacers and the rear mounts and their spacers as they were originally from VW? It seems many people have discovered they are missing spacers or they are in the wrong spot. Your pursuit of the correct alignment is unmistakably correct to do, by the way. Lesser operating angles mean lesser vibration potential.

DougM
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[Landsailer]

All this makes sense. My first instinct was to have it balanced. I will also have a look at the front mount. I am pretty sure the rear two mounts, the ones on the yoke, are all original, never been tampered with. They have the right washer/mount order.

I will also shim up the yoke as much as I can. That won't be too difficult. That will get the diff pointing up a little, which will hopefully be enough.

And, as usual, I will find beer to make this all go better.

I have the DC joint at the trans end. Any thoughts on putting it up front?

[IdahoDoug]

Heh - the beer is always a good lubricant, though I'd think in AK about right now you'd be thinking of hot cocoa with some coffee liquor or similar...

As to the DC location, it would be worth a call to the maker for their recommendation. Also, drive shafts can be "clocked" meaning the joints can be "in phase" or "out of phase" with regards to the yokes (arms) that hold the joints. I don't know if there is a recommendation on the Syncro from the factory service manual but this would be good to know.

As an example, the shafts on my LandCruiser are counter intuitive and mechanics are forever assembling them wrong. The rear shaft should be the more common "in phase" but the front shafts are supposed to be 90 degrees "out of phase". It's a simple thing regarding how you slip the splined section together and someone here should comment because I don't think the factory shaft in the US had a splined section and I'll bet your new one does - giving rise to the possibility of there being a right and wrong way to slip it together for use on a Syncro. You should ID this and have it assembled correctly before handing it to a shop to balance in that correct state.

Anyone know?

DougM
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1988 Toyota Supra 5 speed targa, 2002 BMW 325iX, 1982 Toyota Sunrader

[Landsailer]

So, quick note on progress. After reviewing ragnarhairybreeks info, and seeing that he was facing the same flange difficulty, I pulled all of my mounts on the front diff. After viewing them all side by side, the ONLY mount that stands tall, and by a good bit, is the lower mount on the front. So, that means that mount was pushing the front of the diff up and tipping the back of the diff down, pointing the flange that much further at the ground. I am waiting back on some specs for tolerance of flange height right now, and waiting on the results of the driveshaft balance, and then things will move forward. Anybody else have the new mount height info? I know it seems like I should just buy 6 mounts, but the tolerance height might be good for the community right?

Oh yeah, also constructing a homemade laser flange pointer jobber thing. Hell, it's time to start working every angle.

[insyncro]

I know of a couple different DC units....who made yours?

[Landsailer]

Wessels. And he has been super helpful with troubleshooting everything. I have no problems there. Just wondering how the rest of the community is lining up flanges.

[Jon_slider]

I subscribe to the 4 degree concept, and the both flanges should have the same angle, even if its 2 and 2 instead of 4 and 4, concept.

As I understand it, you want BOTH the transaxle and the front diff flanges to point DOWN by 4 degrees if possible. It is not correct to set both flanges vertically plumb (you should NOT have 0 degrees at the flanges). It is NOT required that the flanges be parallel (eg, 4 down at one end, 4 up at the other). The only requirement is that the angles are the same at both ends, and should not be more than 4 degrees.

I use my iPhone Clinometer app to measure the angles of the flanges.

In my Syncro, the front diff flange has 2 degrees of down angle, AND my transaxle flange also has 2 degrees of down angle.

Im using a Burley slip yoke with Cardan joint, and I have the Cardan at the transaxle end.

Im not using any shims on the front diff, nor on the tranny ears, so the front diff is in a stock position, and the rear flange is angled less than stock, because my tdi motor sits lower than stock.

The "magic" alignment technique is called the Van-Cafe method. It involves loosening the front diff mounts, with the driveshaft installed, then go driving so the whole vibration situation tries to wiggle itself to a place of least resistance, then you retighten the front diff. It helped in my case.

Another thing Van Cafe does, is they put the van on a lift, and run the motor in gear, with the front diff loose. They look at the wobbling driveshaft, and wiggle the front diff around until the wobble is at a minimum..

(assuming the shaft itself is not out of ballance)
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[insyncro]

I would like to add that running a vehicle on a hoist....safely.....should only be done by professionals with a hoist maximum lifting weight well above that of the Vanagon....10k lbs minimum

[Landsailer]

I was thinking I would put it on jack stands, lay under it, and have my wife do 90 while I adjusted the diff.

I will drive it around with the diff loose once I get the flanges lined up. I did get measurements on the mounts by the way:

Top to bottom: 35.5mm
The wide part in the middle (not counting the necked down parts at the top or the bottom): 19mm

[Jon_slider]

Correction, you want the installed driveshaft flange angles to be equal. Since the driveshaft is not horizontal, the way to account for that, is to calibrate the inclinometer to be level based on the driveshaft. Or jack the van up at whatever end is low, so the driveshaft is level ...

That way your flange angles will be in reference to the driveshaft, not the true geographic horizon. And fwiw, the iPhone fits against the flanges without removing the driveshaft. KISS

Let us know how the outcomes of whatever tricks you try. On the condition you do NOT let your wife help, much less drive. That's a recipe for, you know...
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My Soapboxes: Inflation; Handling; Gearing; Decoupling; Swepco

[Landsailer]

If I can't get the flanges to look at each other, which I don't think I will, then I will get the angles equal. I think I can do that.

Also, I don't own, and don't plan on owning, and iPhone (enter everyone's gasps of horror here). But I do have an angle finder and I will set them the same. Then loose diff. Then driving. Then tight diff. Then beer. Beer. And beer.

[Landsailer]

Propshaft was out of balance. Just got it back today. Pulled the trans mounts and they all measured pretty close together and a mm off spec, so I am putting them back with shims to bring the yoke up as high as I can get it. Put the fat mount on the front on the top side and the angle already looks much better.

[Landsailer]

Update: I put everything back together with some shims. I leveled the van, then check the angle on both flanges. Trans flange was 0 degrees. I am assuming this becomes a positive degree when the engine is gassed as the teeter-totter effect of the Zetec engine mounting. The diff flange is down 3 degrees. I don't think that will get much better. The reason being is that, one: I have run out of threads to stack more shims (I could get more bolts, but metrics aren't available on the weekends in AK), two: I could only bring it up may a quarter of an inch more anyway due to the coolant pipes. That might equal 1 degree difference, but that's a big might, and three: I cannot get the front of the diff to come down more, which would actually make a huge difference in angle. So, the first thing I am going to try is flipping the diff around. The advice I have been given multiple times with a DC shaft is to point the non-DC side flange at the center of the other flange. Well, my trans points at the center of the diff, but not the other way around. So maybe backwards will work. If not, I have to shim the engine up to tip the front of the trans down. I don't know how high I can shim the engine because it's really close to the decklid as it stands.

Oh, and the vibrations. With the shaft balanced and the shims, it's still not fixed, but it's better. I get low frequency vibes at 30 and then I get higher frequency vibes as I go up in speed. Not as bad as before, but still there.

In conclusion, why does it always have to be like this?

[Jon_slider]

> why does it always have to be like this?

because your trans flange is at 0 degrees?

Instead of trying to raise the motor, maybe you could shim the trans mounts and get some down angle.

You could also put the DC joint at the transaxle end.. or did you try that already?

good luck, youre almost there, share your success
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[insyncro]

What version Bostig mounting system do you have?

0 degrees is not optimal, my opinion.

Are you also checking the East - West flange angles?

You say the driveshaft needed balancing...is it new or used?