Syncro Prop Shaft Vibration-Searched but need help still

[vwcampin]

I have searched and read most threads on here as well as the Syncro Yahoo group and still am looking for assistance. Here's what we have:

1986 Syncro poptop Weekender 219K
Purchased in May of this year

PO had the driveshaft removed for an unknown period of time. I had him reinstall before purchase as I flew in to buy it and wanted to be sure the 4WD was functional. Had a decent vibration on the way home that seemed to get worse. Ended up removing driveshaft/prop shaft partway through trip home as I didn't want to risk breaking anything and it was getting really annoying . Removing the prop shaft immediately remidied any and all vibration.

Fast forward to a month ago. Had the front end gone through completely. Replaced all rubber bushings, new CV's and ball joints, Van Cafe had a good month! Also had new 15" Rheins and new tires balanced and installed. Took the prop shaft to a local driveshaft shop and had them press in new u-joints and balance it.

Installed the prop shaft, and although much, much better, I am still dealing with a decent vibration. It is most pronounced around 65-70 in 4th gear (about 3500-4000 rpm) There is a definite hum which is worse in the back seat than the front. I tried the Van Cafe method which hasn't yielded any positive results, and I have tried the large 'hose clamp' around different spots on the prop shaft itself which I think helped slightly, but did not resolve.

So I am looking for advice, tips, etc. that I can do rather than starting to throw large sums of money into decouplers, slip yokes, etc.

Has anyone used the Go Westy laser tool rental with sucess?
What else can I do?

All replies appreciated.

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1986 Vanagon Syncro Westfalia Weekender

[edgood1]

In what state is the VC?

If the VC is in the failed/locked state, it can cause vibrations.

Sometimes the vibes come from other things like wheel balance, or possibly the front CV condition.

You said you tried the Van Cafe method.... when you loosened up the front diff bolts and drove around did the vibration go away? If it did that means the vibes are in the prop shaft.

fyi, decouplers don't fix the vibrations.


Loosening the front diff bolts and driving, then tightening them fixed my vibrations permanently(after I had installed a decoupler) after the second attempt.
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1987 Syncro Westfalia powered by Subaru
1963 Panel to Deluxe Bus project :::: (photo album)
'65 Westfalia

[vwcampin]

Thanks for the replies. here are my responses...

[chimivee]

[insyncro]

This topic has been covered hundreds of times here and on the groups.

tire pressure
tire balance
tire tread
torque axle nuts
torque CV bolts
torque lugs
pack CVs
pack wheel bearings
replace propshaft with HD, slip yoke, greasable version
spin balance prop shaft
check all front diff, trans and motor mounts
laser align or VanCafe method

internal bearings and VC have shown vibrations as well.

The "hum" you speak of...is it located around the transmission?
If so, bearings or worse.
Pray its not the R&P, very spendy if needed to be replaced.
dylan

[SyncroGhia]

Just out of interest, how clued up on propshaft universal joints did the local driveshaft shop seem?

I had 2 propshafts gone over by GKN in UK and was amazed to find out that the caps (which hold all the needle rollers) have to be spaced precisely using different thickness circlips in order to get rid of endfloat. This might sound like bul*^hit but I had personally replaced both UJ's on the first propshaft and just fitted the circlips which had come with the UJ's and had horrendous vibrations which I couldn't get rid of and when I inspecting the joints, there was end float allowing the propshaft to move around in relation to the flange.
The technician at GKN had a rack of circlips which were the same diameter but different thicknesses. I have also seen people use shims underneath stock circlips which would work if done carefully.

It might be a long shot but if you can feel any sideways movement (endfloat) in the UJ's at all, I'd bet that's your vibration.

MG
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[vwcampin]

Dylan,
It is hard to say where the 'hum' is, but it appears more prevalent in the rear when sitting back there, than from the drivers seat. Not sure if that is simply because of the volume of the rear causing it to resonate more, or if it truly is located towards the transmission.

Since you are hoping that it is not the transmission, when I indicate that removing the prop shaft causes all vibrations and hums to cease point away from the transmission as a culprit?
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1986 Vanagon Syncro Westfalia Weekender

[insyncro]

No,
Removing the prop shaft will eliminate most of the vibrations no matter where they are coming from as power is not being transmitted to the front diff and all associated parts.
If there is less of a hum without the prop shaft, that is still a hum and needs to be checked out. Hums and whines are usually ring and pinion related. The most costly parts in the trans and diff. Spun bearings will make noise as well.
At my shop I run vans in each gear with them on the hoist to locate all noises. Using a listening device helps a lot.
I am in Hudson, NY and get vans from all over to help cure this exact issue.

dylan

[vwcampin]

Dylan,
There is zero hum with the prop shaft removed. The hum is more of a vibrational one, as if the van itself is slightly resonating because something is vibrating. Maybe my description is off. Too bad I moved from where I grew up in Upstate NY as it wouldn't be too bad a drive.

Edit: Maybe hum is a bad description, it is more of a drone...

SyncroGhia,
The place appeared to know what they were doing. When I picked it up they mentioned that they had to special order the UJ's and had to find a circlip that fit just right. Before installing I did not notice any play in the UJ's at all.
_________________
1986 Vanagon Syncro Westfalia Weekender

[whynotvw]

maybe you can call Go-westy and get some help. gowesty people are usually very helpful.

[insyncro]

Sometimes sounds come via the shifter linkage.
The later Syncros had a linkage protection cover that is attached to the skid rails. Check to see if you have this part and if it is touching anything but the skid rails.

[euromog]

Just to get some possibilities out of the way.
Does your syncro have a WBX installed?

Have you had the rear axles removed and the CV's inspected and replaced as needed?

Have you replaced the rubber mounts for the front diff and at the front of the transmission?

I think your vibration is coming from the prop shaft. The fact that the vibration is now less after rebuilding points to it. However the success rate of replacing the u-joints in the original prop shaft and have it run vibration free are very low. That is why I came up with my own all new prop shaft that compensates for irregular angles and runs smooth. However you must cover all the basics that have been reccommended to you first to eleminate any other mechanical problems.

[burleymotorsports]

The original driveshafts have the u joints sweged in and are really not made for service. BMW and MB do the same thing. In the end of that shaft where the rubber flex coupling is , if you disassemble that section you will find a short shaft that goes inside the main shaft, there is a bushing in there that wears out and causes misalignment issues, also when the driveshaft is removed flex the u joints back and forth if they feel notchy or unsmooth, the driveshaft is done. Burley Motorsports makes a really nice driveshaft with an old school cv joint on the back section,greasable slip yoke on the front, completely servicable by the home mechanic, uses top quality spicer joints with grease fittings, directly bolts on,is heavy duty yet light enough to not cause excessive wear to your drive train. The stock drive shaft likes to be in perfect alignment, ours likes to be out of alignment. Takes all that Monkey motion of driving around with your diff loose and laser pointers out of the deal so you can enjoy your Syncro. Check it out heres a link . Cheers Burley http://burleysmotorsports.com/index.php?main_page=...u8gvb43oh0
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[EwokPoacher]

i had the same problem with the vibration. i have been living with it for 1 year and it progressively got worse. 3 weeks ago, i had it removed - and all vibration went away. i decided to order a new driveshaft from gowesty - the doka variety. i have had no vibration since putting in the new driveshaft. i went to mogfest and did some off-roading this past weekend and came out with no problems.

[burleymotorsports]

Yes Syncro driveshafts are notorious for vibrating. Thats great news that your is fixed now
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[whip618]

I rebuilt my top end a year ago and after installing the motor I had a vibration aorund 45 mph so I removed the drive shaft and one of the u-joints was so dry the rollers fell out in a cloud of rust dust.

Replaced both u-joints with the neapco brand and had to shim both to get them tight plus do a little machine work on the grease zerks so the u-joint would swivel without binding on the zerk.

Reinstalled the shaft and it still vibrated at about the same speed so I built a laser alignment tool because I didn't care much for the loosen the front diff and drive it until it aligns itself method and the laser really did the trick, it's been smooth a glass ever since and it only cost me about seven dollars to build.

Phil
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[IdahoDoug]

So, the factory front shaft cannot be lubed even if removed for servicing? Someone mentioned swaged which usually means it's not designed to be opened up. Could a reasonably determined person get it apart, cleaned and lubed and then reassemble exactly to keep the clearances where they were? Or is that a nightmare? How about a shop if I were clear it had to be reassembled EXACTLY as found?

I'm about 6 months from driving my Syncro for the first time and it's gonna bum me out to find I have vibrations and could have serviced the shaft.

Thanks,

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

[SyncroGhia]

Doug,

The UJ's used in our syncro propshaft are also used in agricultural machinary and when used in that application, they have a grease nipple in the middle of X. Unfortunately due to the VW design, there isn't enough room to get the grease nipple in there, let along get anything to it.

The guy at GKN was fairly harsh with how he fitted and tested shimming up the end caps but fitting and then (ahem) clouting the joint hard one way and the other and then felt for endfloat. In this way, you ensure that the cap is pushed back against the circlip fully. It's very easy to fit the circlip and it 'feel' great but the cap hasn't moved back into place yet.

So far as I'm concerned, anything which is designed to come to pieces is designed to be rebuilt and that includes the syncro propshaft.

Vwcampin, I'd get underneath your syncro and grab hold of the propshaft and see if you can feel any play at all in any direction. There will always be rotational freeplay.

You can have a vibration caused by a bad CV joint and it will only be obvious when you're running 4WD as this is the only time that you have constant torque being fed through the system via the VC. As suggested by Euromog, I'd pull off each driveshaft and inspect (very carefully) each CV joint individually. It's a very messy job but once you've gotten the hang of it, it's not so bad. It will also stand you in good stead for having to replace one on the road side in the future.

MG
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[vwcampin]

Thank you everyone for all of the replies and suggestions. To answer a few questions, yes it is still the stock 2.1 WBX, no I haven't removed and inspected the rear CV's, but front are newly installed.

Whip618, can you share how you built your laser alignment tool?

I will get to the bottom of this and update this thread accordingly. Life tends to get in the way, so it may take some time. I have some great suggestions and now need some time to work on the Syncro.
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1986 Vanagon Syncro Westfalia Weekender

[vwcampin]

This weekend I ended up pulling the driveshaft back out.

SyncroGhia, the driveshaft was tight with no play.

Actually, I pulled the driveshaft and swapped it end to end, with the guibo now sitting closer to the front dif than the transmission. As far as I could tell, it simply made the vibration more pronounced in the front of the van than the rear, which is leading me to think the driveshaft is pretty much used up (minus removing guibo and re-doing the brass bushing, etc.) So I pulled it off, so I can still drive it around a bit before winter hits and it goes into hibernation.
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1986 Vanagon Syncro Westfalia Weekender